AP Biology 2007 (Period 8&9)

Mitosis

2008-02-26T18:18:00.000-08:00

A cell undergoing mitosis goes through Prophase, Metaphase, Anaphase and Telophase.

Interphase:This stage prepares the cell for mitosis. The nucleus in this stage is well defined and has DNA loosely packed in long chromatin fibers. This stage is when the cell is preparing for mitosis, and replicates chromosomes and produces proteins and organelles. During the synthesis phase of interphase, the dividing cell replicates and must separate DNA copies correctly to two daughter cells. The DNA is then organized into chromosomes. After the DNA is copied, the chromatin condenses and makes a smaller package. A mitotic chromosome is a duplicated chromosome and it contains two sister chromatids which contain identical copies of DNA.

Prophase: In this stage, the chromatin condenses and the chromosomes are visible. The centrioles move to opposite poles of the cell (in the animal cell) and the protein fibers cross the cell to form mitotic spindles, also called microtubules which are made of actin and myosin. During this stage, the nucleolus disappears and the nuclear membrane breaks down.

Metaphase: the early stages of this phase are known as prometaphase. This is when the spindle fibers attatch to the centromeres, creating kinetochores. Microtubules attatch at the kinetochores and connect the centromers to the centrioles. Then the chromosome begins moving, and enters into Metaphase. Metaphase is when chromosomes align along the middle of the cell. The spindle fibers coordinate the movement and help ensure that the chromosomes separate properly.

Anaphase: The sister chromatids separate at the kinetochores. They are pulled at the centromeres and move to opposite poles. They are pulled by motor proteins "walking" along microtubules. These proteins are actin and myosin, and this also phase also has an increasement of ATP by mitochondria. The poles move farther apart and the microtubules lengthen. A separation off chromatids occurs in anaphase as well, where the proteins holding together sister chromatids are inactivated.

Telophase: This is when chromosomes arrive at opposite poles and daughter nuclei form. The nucleoli then form and the chromosomes disperse and are no longer visible under light microscope. The spindle fibers disperse and cytokinesis begins.

Cytokinesis is cell division. In animals it is a constriction belt of actin microfilaments around the equator of the cell. The cell is split into two. In plants a cell plate forms, and the vesicles line up at the equator. A new cell wall is laid down between the membranes, and the new cell wall fuses with the existing cell wall.

The Cell Cycle.

2008-02-25T16:11:00.000-08:00

Cell Division..........................Why?
- To make new cells
- Continuity of life: Asexual reproduction, growth, repair, and renewal
- Cell cycle: Make a copy of a preexisting cell (Daughter cells)

What's in a cell that smells so sweet.......ehhh

- Nucleus: Chromosomes, DNA
- Cytoskeleton: "Scaffolding" or "Skeleton"; The internal framework of a cell, composed largely of actin filaments and microtubules (spindle fibers). Also includes Centrioles (in animaks).

The Nucleus:
Its function: to protect DNA

It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these chromosomes are the cell's nuclear genome. The function of the nucleus is to maintain the integrity of these genes and to control the activities of the cell by regulating gene expression.

The Nuclear Envelope: a double membrane that contains pores to allow large marcromolecules to pass through such as ribosomes.

The Cytoskeleton:

Its function: to provide structural support, maintain shape of cell, provide anchorage for organelles via protein fibers (microfilaments, intermediate filaments, and microtubules).

The cell may become motile by cilia, lamellipodia or flagella.

The cytoskeleton also organizes structures within the cell and its activities.

Centrioles:

One of two cylindrical cellular structures that are composed of nine triplet microtubules and form the asters during mitosis.
Centrioles are involved in the organization of the mitotic spindle and in the completion of cytokinesis.
Centrioles are an important part of centrosomes, which are involved in organizing microtubules in the cytoplasm.

They organize spindle fibers and guide chromosmes in mitosis.

Daughter Cells:
During mitosis, an exact copy of DNA is made from the parent cell to be passed to the daughter cells.
Cytokinesis: division of orgnanelles and cytoplasm

Mitosis:

Interphase: Defined only by the absence of cell division. During interphase, the cell obtains nutrients, and duplicates its chromatids. Most eukaryotic cells spend approximately 90% of its life in Interphase. "Every day job": produces RNA, synthesize proteins and enzymes, prepares for duplication if triggered.

Prophase: Stage during which the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus forms at opposite poles of the cell.

Pro-Metaphase: The stage of mitosis or meiosis in which the nuclear membrane disintegrates, the centrioles reach the poles of the cell, and the chromosomes continue to contract.

Metaphase: Condensed chromosomes align in the middle of the cell before being separated into each of the two daughter cells.

Anaphase: The chromosomes move from the equatorial plate toward opposite ends of the nuclear spindle.

Telophase: The chromosomes of daughter cells are grouped in new nuclei.

Cytokinesis: The division of the cytoplasm of a cell following the division of the nucleus.

Cell Life Cycle:

Interphase:
Divided into three phases:
-G1: first gap
Cell doing everyday job
Cell grows
-S: DNA Synthesis: Copies chromosomes
-G2: second gap
Prepares for division
Cell grows more
Produces organelles, proteins, and membranes

FIN

Oh tomorrows sherpa is...............Maria

Science Debate 2008

2008-02-22T10:51:00.000-08:00

Have you seen this:
http://sciencedebate2008.com

Would be great if you students got to see this.
==========================================

Universities, corporations and a host of individuals are calling for a debate with all four of the remaining presidential candidates discussing critical scientific issues that impact everything from the environment to the economy.

Sciencedebate2008.com, formed by two Hollywood screenwriters who had time to mull science recently while on strike, is an effort aimed at thrusting technology into the limelight.

One of the initiative's founders, Shawn Otto, said yesterday more than 17,000 American universities and the editors of nearly every major science publication in the nation have added their names to the Web site, encouraging the presidential hopefuls to debate key scientific issues.

"This is a nonprofit organization we set up to raise the profile of science and technology in our national political diaglogue," Otto said, adding that his initiative is now being co-sponsored by the National Academy of Sciences, the Institute of Medicine, the National Academy of Engineering, the Council on Competitiveness and the American Association for the Advancement of Science.

Yesterday, John Podesta, chief of staff for former President Bill Clinton, posted a video statement on YouTube echoing that science remains one of the nation's primary areas of focus. He called for a presidential debate "in charting a path forward on national security, on energy and climate change policy, really on the core fundamentals of our economic policy."

Otto said it would be "really fabulous" to see Democrats and Republicans on the same stage debating issues in science.

"All of us believe that almost every major policy challenge that the next president will face revolves around questions of science and technology," Otto said, referring to signers of his initiative.

"Ever since World War II, America has been leading in science and technology, and science and engineering have driven half of our economic growth."

But in the not-too-distant future, he added, 90 percent of all scientists will be living in Asia, causing a major "shift in intellectual capital."

James McCarthy on Science Debate 2008

John Porter on Science Debate 2008

Francesca Grifo on Science Debate 2008

THE ENDOCRINE SYSTEM: HORMONES

2008-02-11T15:42:00.000-08:00

The Endocrine System is basically a communicating system for the body. Multicellular organisms need to communicate from cell to cell to maintain homeostasis. Hormones are used in regulation. The other regualting and communicating system is the nervous system. Cells interect with each other through neurons. An electrical signal is released by ions flowing through a membrane. Neurons have fast, short-lasting responses. Hormones have slow, long-lasting responses. Hormones are chemical mesesengers that are released in one part of the body and affect another part of the body. Hormones have long term effects such as in

metabolism
growth
development
maturation
reproduction

Hormones are released by ductless glands. Ductless glands are tissies that produce hormones and release the hormones directly into the bloodstream. Duct glands like the pancreas produce the enzyme and release them into another area through tubes like how the pancreas releases into the intestine. Hormones are specific to the target cell. Another theme is seen here, the lock and key mehtod. The hormone fits into the receotor proteins that the hormone attaches to specifically only to ones that have the shape that can fit with the hormone.

There are 2 major types of hormones:

Protein-based Hormones

These hormones are made of proteins including polypeptides suc as insulin and ADH (anti diuretic hormone). Glycoproteins are toher protein hormones that have proteins and carbohydrates. These include FSH (Follicle stimulating hormone) and LH( luteinizing hormone). Amines are another type which are modified by amino acids like epinephrine and melatonin. Protein based hormones are hydrophillic and are not lipid soluble. That means they can't diffuse across a membrane. The protein hormone has to bind to receptors on top of the plasma membrane that are embedded in the membrane. The homrone fits into the protein in the membrane and causes a conformational change. The protein that receives the hormone stimulus changes chape which causes another protein at the other end to carry the message along. This secondary messenger pathway is triggered. Enzyme action, uptake or secretion of molecules is activated.

2. Lipid-based Hormone

These hormone include steroids which are modifed cholesterol such as sex hormones and aldosterone. Lipid based hormones are hydrophobic which means they are lipid soluble. They can diffuse right through the cell membrane without being stopped at the cell membrane and having to go through a receptor on the membrane. These hormones bind to receptor proteins in the cytoplasm and some on the nucleus. Lipid hormones bind to DNA as transcription factors. The hormone causes a conformational change. The transcription factor is the protein on the DNa that coordinates which genes should be transcripted onto the mRNA to make a protein. Lipid hormones are carried on a protein carrier because they are not soluble in water since oil and water don't mix. The hormone can cause a major long term change in the body such as growth. The growth factors can affect hair, bone, muscle and gametes.

Oh Yeah Tuesday night's sherpa will be Shannah.

Well, well, here it is--the missin' blogs: B CELLS (2/6) & T CELLS (2/8)

2008-02-10T15:25:00.001-08:00

WOO HOO THE 3rd Line of Defense is Acquired Immunity B CELLS & T CELLS

Well first and formost i would like to appologize to my fellow class mates as i always do for not having the sherpa repost in on Time.... ma bad. Well the library is a quiet place to work so i guess this is where i'll be writtin from.

Iight:

..... The 3rd line of defense in the immune system is Acquired Immunity which consists of specific defenses: lymphocytes (B cells and T cells) and antibodies(immunoglobulins).

This defense mechanism is activated in reponse to antigens on pathogens that are not recognized as self-cells or home-cells.

Antigens are proteins that serve as nametags for the t cells and b cells to recognize if a cell is a home cell or a foreigner.

B Cells mature in the bone marrow and belong to the humoral (body fluids) response system.
T cells mature in the thymus and belong to the cellular response system.

B Cells
There are two types of B cells: plasma cells and memory cells. The plasma cells produce anitbodies and make memory cells. The memory cells have a long term immunity to a specific antogen. They are the defense against attackers that are floating freely in the lymph and blood.

Antibodies: proteins that bind to specific antigens.
IgM: 1st immune response.
IgG: 2nd immune response: more antibodies in plasma
IgA: in external secretions
IgE: release of histamine, triggers allergic reactions

B cell immune response system.

T Cells

An immune response to infected cells(pathogens inside cells).

They are the defense against non-self cells.

The two types of T cells are Helper T Cells and Killer T Cells.

Helper T Cells alert the immune system of intruders.

Killer T Cells attack the infected body cells

T cells know that a cell is infected when there are antogens of a foreign invader on the outside of the cell. The infected cell digests the pathogen and the MHC carry the pieces to the surface kind of like a wanted poster.

The Helper T cell then releases interluekin 1 to produce more helper t cells to look for more infecter cells. It also releases interleukin 2 to alert the Killer T cells that there is an invader. This activates the Killer T Cells. The interleukin 2 also stimulates B cells to drop more anti bodies in case there are whole pathogens in the humoral system.

The killer t cells destroy the infected target cell by making holes in it (apoptosis). Since the membrane is now punctured the cell is no longer semi permeable it is wholy permeable and water rushes in from a hypotonic solution to a hypertonic solution and the cell pops.

THATS ALL FOLKS

PS If youre really feeling like a nerd play an immune system game:
http://nobelprize.org/educational_games/medicine/immunity/index.html

Monday Nights Sherpa Will Be SAAD. =)

2008-02-07T15:17:00.000-08:00

Since someone did not post a sherpa last night i am now stuck with this job, and ofcourse im thrilled!!! =)

B cell immune response

-plasma cells = fast response

-clone

-release antibodies (proteins)

-memory cells = long term immunity

VACCINE'S

Vaccinations have proven to be a successful way to fight virus'. A person is exposed to a small amount of the virus which is not enough to be a danger to them. This is the beginning of active immunity. In other words resistance to the disease or infection. The body then makes antibodies against the antigens that are causing the disease. The antibodies work to get rid of foreign invaders. Jonas Salk developed the first vaccine which was against polio (which attacks motor neurons).

JONAS SALK

BREASTFEEDING (MATERNAL IMMUNITY)

Breastfeeding is a way of a child obtaining antibodies from their mother. Breast milk protects infants from bacteria and virus. It also helps the baby fight off infection and disease. They can also be passed across the placenta. This makes breastfeeding a very important contributor to a childs health.

-kerrie- p.s.- the sherpa for tom. will be saad

Immune/ Lymphatic system 1

2008-02-05T12:49:00.000-08:00

Today we learned about the immune and lymphatic system.

There are many avenues of attack for foreign substances to enter your body.

digestive system
respiratory system
urogenital tract
break in the skin

Once their in your body they can either use the circulatory system or the lymph system to go around your body. A body needs an immune system to protect it from viruses, bacteria, fungi and protists that are going to use the body as a tasty nutrient & a vitamin-packed meal. Also your body can be attacked from the inside by abnormal body cells like cancers. The lymph system is made fore the production and transportation of leukocytes and to trap foreign invaders. Only white blood cells travel through this system. It consists of lymph vessels which are intertwined amongst blood vessels , and lymph nodes which are made to collect foreign invaders.

Red and white blood cells are made from pluripotent stem cells in the bone marrow. These stem cells are then made into lymphoid stem cells and myeloid stem cells. The myeloid stem cells make red blood cells , basophils, eosinophils, neitrophils, monocytes, and platelets. Lymphoid stem cells make either B-Cells or T-Cells. B & T cells are the true immune system.

The first line of defense

Broad, external defense. such as walls and moats. this is the skin and mucous membranes. The skin includes external and external skin.

The physical and chemical defenses are non specific. The external barrier are epithelial cells and mucus membranes such . Examples are the skin, the respiratory system, the digestive system and the urogenital tract.

The chemical carriers on the epithelium are skin and mucous membrane secretions. Sweat, tears, mucus, saliva, stomach acid and anti-microbial proteins (such as lysozyme enzyme)

The Second Line of defense inclcludes internal, broad range patrol by many different cells and proteins such as mast cells, monocytes, macrophage and natural killer cells.

Leukocytes or phagocytic WBC's. Their attracted by a chemical signal released by damaged cells. Neutrophils are the most abundant and have a three day life span. Macrophages are "big eaters" and are long-lived. Natural killer cells destroy virus-infected cells and cancer cells.

In order to kill cells tho have gone bad , natural killer cells perforate cells, by releaseing perforin ( a protein) into the membrane of a target cell.. This forms a pore allowing fluid to flow into the cell. The cell then ruptures or lysis. This is call apoptosis. As Ms. Foglia says, its like "causing a cell to commit suicide"

Anti - microbial proteins awork as a complement system. 20 proteins circulating in blood plasma attack baterial and fungal cells. This forms a membrane attack complex which perforates target cells which also leads to apoptosis.

Inflammatory response is when damage to tissue triggers local non-specific inflammatory response. The cells then release histamines and prostaglandins. Capillaries then dilate and become more permeable This : increases blood supply, delivers WBC, RBC, Platelets & clotting factors. This accounts for swelling, redness and heat of inflammation & infection.

i cant get pictures because my computer is being difficult, i'm sorry this was boring, BUT tomorrow's sherpa will beeeeeeee...... KIM :)

GoodNight.

Muscle System

2008-02-04T16:50:00.000-08:00

Last week we learned about muscle. Muscle is broken down into three different categories
Smooth Muscle- Involuntary, Non-striated Muscle found in the digestive tract
Skeletal Muscle- Voluntary, Striated Muscle usually attatched to skeleton used to create movement
Cardiac Muscle- Involuntary, Striated auto-rhythmic, found in the heart

There are also three types of joints:
Ball and Socket Joints- Allow for 360 degree rotation example of this is the shoulder joint
Hinge joint- Allows for forward and backward motion such as that in your knee
Pivot Joint- allows for twisting motion such as that in your wrist or ankle

Muscles do work by contracting. When you flex your muscle the muscle shortens and thus enlargen in width. Skeletal muscles come in antagonist pairs flexor v. extensor: when flexing the bicep the bicep is contracting becoming the flexor and the tricep is stretched becoming the extensor. Tendons connect bone to muscle where ligaments connect bone to bone. Sarcomere is the unit responsible for muscle contraction, made up of thin and thick filaments Actin and Myosin. These interact at cross bridges between myosin heads and actin which are responsible for the shortening in muscles. The cleaving of atp to adp allows for myosin heads to bind to the actin filament. The shortening of the sarcomere allows for the contraction of the muscle when the (Z lines) move closer together.

The "Ratchet" System is due to the bonding of myosin with actin, then the sliding of thin and thick filaments past each other, then myosin head releases and binds to the active site on actin, and the muscle is unable to relax until Ca+2 is repumped into the sarcomeric reticulum. When all of this occurs the ratchet of the muscle occurs and muscles contract. For this to occur ATP is needed and greatly appreciated.

2007-12-11T11:59:00.000-08:00

Today ... we learned alot....

Posted by SeungS at the real slide is actually down there..

______________________________________________________
Metabolism and Enzymes... whoop dee doo...

Basically everyone says we need to eat to live and now you know why thanks to Ms Foglia hoorah for the teacher
anways the reason we need to eat is because we need energy and without it we would.... die.
ok so energy originates from the sun yay sun good for you then if the Earth is lucky being far and all gets some solar energy plants absorb it using there chloroplast from solar to chemical energy
This is where we need to eat to live comes in.
The food pyramid is actually a energy pyramid where the producers which are the green stuff (plants) get eaten by the... moving stuff (animals) called the primary consumers! then the secondary then the tertiary and so forth... not important moving on...
We basically need the energy for the basic 4 things proteins, carbohydates, those shapeshifters.. lipids, and personally my favorite sugar..
Now we don't have chloroplast I mean itd be awesome if we did but we dont.. so get over it...
Instead we have the ability to be the dominant life on earth by stealing from the producers by.. killing them! then using our mitochondria to spread the love(energy) IMPORTANT EVER LIVING ORGANISM HAS A MITOCHONDRIA so dont be a du*ba** and think only animals have them
now going back to the topic! all living organisms store energy and plants especially store energy to get eaten not suppose to be there goal but this is how GOD intended it to be and by that I mean being eaten by the primary consumers
All those "complications" of taste and looks of food are nothing all that matters about food is the raw materials and energy we get from them!
okay just for the people who are like "hmmm why are we storing this garbage?!"
well we store it because its not garbage but because ATP is unstable and we need it for future references.. DUH! also ATP is Adensine Tri Phosphate or simply put energy yeah!
So recap energy comes from the sun-solar energy which has ATP and organic molecules then to the plants then animals then other animals then we eat all of them! yummy..
Metabolism is how we get and use energy
We as living breathing aroused organims break and form bonds between molecules which is broken down to anabolic and catoblic.
anabolic is the building like BOB the guy who builds stuff
and catabolic is like Geroge W. bush who constantly breaks stuff especially Iraq and ocassionally the English language.
Anabolic is characterized by dehydration synthesis and synthesis which are difficult words meaning build see people have to make life difficult by making many different words for 1 freakin' meaning!
Catabolic has hydrolysis and digestion also kind of annoys me..
these also cannot be done without a little help from the AMAZING!!

ENZYMES!!!!
The enzyme is needed to disturb and destabilize bonds between molecules to bond them together and take them apart. basically I would call the enzyme as
MARRIAGE AND DIVORCE
To digest molecules we need less organization because there is a lower energy state and this is done by another word that makes life difficult... exergonic which means gives off energy this can only be done through catabolism haha cannabalism.. gross
to build molecules we need more organization which is a higher energy state and you guessed it anabolism.. if you dont get it I really don't know how to spell it out for you anymore... (very slowly) we. need. more. energy. to builllldddd.
we need to build and break down at the same time as well because we need to break down materials for the energy to build more molecules using the energy just made..
WARNING NOT IMPORTANT THE THING IN GREEN
come to think of it why don't we just not break things down huh?! JUST KEEP THE MOLECULE WITH ENERGY AND SLAP IT ON TO A THIGH!!!!
haha its basically the same thing as storing energy onto a thigh and later we can break it down yay procrastinators.. for those of you who don't know what procrastinators are first of all get a dictionary and look it up second of all learn some more english words and third it means people who always put stuff off until later..
hey heres something intresting.. paper is made from sugars but it tastes like c -r- AP and we all know AP stands for Autopilot so I said nothing wrong if you happen to get the joke it was unintentional and not my fault!
anyways paper is made from cellulose which is made from sugars but only some animals can digest cellulose so we have something else.( also those dumb animals think there better than us but we have the opposable thumb so HA! take that animals )
okay comubstion breaks down sugar which is a rapid break down but we cant do that because this combustion is at 451 degrees f and I don't know about any of you but personally I don't feel like being set on fire or boiling from the inside out...
instead we as humans break down the sugar slowly and little by little with thing called the .. THE ENZYME DUN DUH DUN DUH!!!
the reason behind the need of such an awesome thing as combustion to break down sugars is because unlike our hydrogen bonds these bonds are mucho stabile and mucho covalent so its hard as h-e double hockey sticks! Combustion basically is only required for high activation energy like sugar
The amazing enzyme is what we genius with alot of vocaulary call a catalyst
which reduces activation energy to like nothing yesss!! its like buying Gucci for the price of KFC
anyways we will all die... if the activation energy were still really high without the help of the catalyst enzyme
Now people have thought enzymes were only proteins...
but they were wrong... dead wrong...
actually recently it has been discovered that there is a rebel called the RNA which "is an enzyme but not yet a protein"... sounds like a Britney Spears song which one?
who cares?!
now fortunately for me this is all we learned today so HA! na na na na

also the next sherpa to take time out of there life to do this is....
Krystyn!!! jk its Marc :P

oh and teacher lady the time is wrong i published this at 4:12 P.M and one last thing theres no pictures but im pretty sure its a d*m good read
ooo last thing I promise. is it sherpa or shurpa?

nervous systems- Brain development

2007-12-09T13:19:00.001-08:00

Thrusday in AP Biology we discussed the brain which plays a major part in our nervous systems.

Our nervous system is in two parts the Central Nervous System and the Peripheral Nervous System.The CNS ( central nervous system) is made of the brain and spinal cord containing mostly interneurons, also known as associative nuerons and commonly called brain nerves. They recieve signals from the sensory nueron and send the signal to the muscles which are moved by the motor neurons. The PNS ( peripheral nervous system) is made of the sensory pathway which recieves information comming in from the senses and Motor pathways which send information to muscles. The motor pathways is divided into two group Somatic(voluntary) and Autonomic(involuntary). The somatic controlls things liek muscle movements we can control and the Autonomic controls things like our heart rate and digestive system. The autonomic nervous system can then be divided into the sypathetic and parasympathetic divisons. sympathetic controls our arousal and energey used in a "fight or fight" response which the parasympathetic calms and brings us to an easy resting and digesting state.

Cephalization is the clustering of nuerons in the brain at the front end of a bilaterally symetrical animal. The brain is at this location becuase it is where the majority of our senses are located. Organisms with radially or no symetry contain nerve nets such as the cnidarian which has no complex actions becuase it ahs not complex nervous system. orgnaisms wiht radilaly like echinoderms contain more organization but their base on nerve nets still limits complex movements. Organisms containing a brain and CNS have more complex muscle control. once a Brain is developed peripheral nerves can begin as well as an increase in internuerons. most complex brains are found in predator mollusks.

The evolution of vertebrate brains shows and increase in size and complexity of the forebrain and it shows the dominacne of the cerebrum which controls higher order thinking, which explains why humans have a larger forebrain and cerebrum than for example sharks or frogs.

The human brain consists of the forebrain, the midbrain and, the hindbrain.The hind brain are the oldest structures the provide autonomic and body functions. this includes the pons, medulla oblongata and cerebellum. the structures help in the cordination of movement such as blance the maintence of homeostatis and impulses to higher brian orders as well as many involuntary actios like breathing and heart rate. The midbrain is involved in the intergration sensory information, including visual and auditory reflexes. reticular formation controls our sleep and awakefulness which can be seen through an EEG by showing electrical activity, the more activity means the more change in electrical charge. The forebrain contains the most highly evolved structures in the human brain, it hold the cerebrum which is divided into two hemipheres left and right which control the opposite side fo the body, these hemispheres are connected between the corpus callosum. The left hempisphere coontrosl many functions involving school and thinknig, like language math and logic while the right hemisphere controls the socialness, artistic ability and creativeness, ect. the cerebrum is divided into lobes with different function the frontal which controls reasoning, temporal controllingg auditory, occiptal controllingg eyesight and parietalcontrollnig senses. The limbic system controls basic emotions. we also all ahve reflexes which are autonomic responses for survival. They are reations without going to the brain.

That concludes the nervous system and basic brain development.

tomorows sherpa will be.. seung ??

The Nervous System (cont.)

2007-12-05T13:26:00.000-08:00

Today in 8th and 9th period AP bio we discussed the Nervous System. I'm going to start off with reviewing some of yesterdays lesson because it will help lead into today's lesson.

Well, first you want to know how a nerve impulse travels. An impulse starts with a stimulus and then the nerve is stimulated. The cell is originally negative on the inside and positive on the outside. Once it reaches threshold potential it opens up the channels in the cell membrane. The example we used in class was Na+ and K+. Once the Na+ channels in the membrane open up, the cations diffuse into the membrane. This causes the cell to become depolarized. That point on the neuron then becomes positive inside the cell, and negative outside because the charge of the sodium is positive. This needs to continue down the cell so in order for this to happen the rest of the gates need to open. The change in charge opens up the next Na+ gates down the line. These are called voltage-gated channels. This wave that moves down the neuron, the nerve impulse, is called action potential. Once this occurs the cell has to be re-set to the negative charge inside and positive outside. This is changed by a 2nd wave. This time the K+ channels open and the potassium ions diffuse out of the cell. This makes the inside of the cell negative, again and the outside positive. The combined waves travel down the neuron and in one direction. The wave is an active potential/nerve impulse, that travels from our brain to fingertips in milliseconds. The voltage-gated channels open and close in response to changes in charge across the membrane. The sodium channels open much faster than the potassium channels. But they both close slowly.
After this a neuron needs to re-set it. This happens by the Na+ moves back out and then the K+ moves back in. They are both moving against concentration gradients. In order to do this they need a pump. The sodium-potassium pump requires ATP. This pump allows 3 Na+ ions to be pumped out and 2 K+ ions to be pumped in. Now the neuron is ready to fire again.

Heres a video on this process:

Here is another video:

At the end of the axon the signal needs to make it to the next nerve cell. In order for this to happen the impulse needs to jump the synapse. The synaptic terminal releases neurotransmitters and the diffusion of chemicals across the synapse conducts the signal across the synapse. At the synapse the action potential depolarizes the membrane, which then allows the entrance of Calcium, which allows neurotransmitter vesicles to move and fuse with the membrane and release it to the synaptic cleft. The neurotransmitter than binds with a protein receptor, the ion-gated channels open and the neurotransmitter is degraded or reabsorbed. In the next nerve cell the chemical signal opens the ion-gated channels and Na+ diffuses into the cell and K+ out of the cell.

Myelin Sheath
The axon of nerve cells is wrapped with a set of cells, Schwann cells. These cells insulate the axon and causes the signal, sent to the nerve, to hop from node to node. The hoping from node to node is called saltatory conduction. This increases the rate 30x.
There are some times when the myelin sheath is attacked by the immune system. This cause a loss in signal and is a disease called Multiple Sclerosis.

Anything that affects neurotransmitters or mimics then affects the functions of the nerves. Gases, mood altering drugs, hallucinogenic drus, Prozac and poisons all affect nerve function.

We also discussed the some of the different kinds of neurotransmitters. Acetylcoline-transmits signal to skeletal muscle
Epinephrine and norepinephrine- fight or flight response
Dopamine- affects sleep, mood, attention and learning. Lack of dopamine-associated with Parkinson's disease. Too much-schizophrenia
Serotonin- affects sleep, mood, attention and learning

One more note: Acetylcholinesterase is an enzyme which breaks down acetylcoline neurotransmitter.

That concludes my sherpa report.
Tomorrows sherpa will be.....Kelly Prince.

Kidney's yey!!

2007-12-04T19:44:00.001-08:00

Well as it always seems i useally get the longest powerpoints to do but thats ok challenges are good.

Mammalian System
Its key functions are...
Filtration- Collects blood and filters out water and soluble material.
Reabsorption- reabsorbs needed substances (water NaCl) back into the blood
Secreation- pumps out unwanted substances to urine.
Excretion- removes excess fluids and harmful toxis from teh body

Nephrons
One of the main parts of the kedney is the Nehron. Each KIdney has 1 million, yes million (thats alot) nephrons. Its function is to filter out urea & other solutes (sugar salts). The process is the Nephron filters blood plasma (the liquid part of the blood) through it. Valuable solutes and water are reabsorbed.
Filtered out- Water (good) glucose (good) salts/ions (good) urea (bad very bad)
Not filtered out_ cells and proteins (toob ig to fit through the membrane).

KIdneys
THe kidneys are an interaction between the Circulatory sustem and exretory system.
The Circulatory cystem includes the glomerulus (a ball of capillaries).
The ecretory system includes- nephrons, the bowmans capsule, the loop of henle, and the collecting duct.

nephron re-absorption
Proximal tubule- the 1st series of loops in the nephron. Most of the "good stuff" is re abosrbed bak into the blood here.
NaCl- Na+ is re-absorbed by useing atp and Cl- follows by diffuseion. This process only takes half teh engery needed to absorb NaCl regullary.
ALso Absorbed- water glucose and HCO3.
Loop of henel
-Decending limb
high permiablility to water. This is becasue it contains many awuaporins in cell membranes. Low permiability to salt, this is because its missing salt channels.
-Ascending limb
Low permeablity to water, lack of aquaporens. It contains a CL- pump Na+ follows it by diffusion. Different membrane proteins. This means salts are reabsorbed.
Distal tubule Salts water and HCO3 are reabsorbed.
Collection Duct- Water is reabsorbed
. Urea is passed through the bladder and exreted.

TO do all this diffusion Osmotic Control is uised int he nephron. This reduces the cost of energy. This is because diffusion is used instead of active transport.

Regulating the Internal Environment

2007-12-04T14:51:00.000-08:00

Today we learned a way cells maintain homeostasis. Negative feedback occurs, this is where different receptors and effectors bring about a reaction to maintain the favourable balance.

During class we went over a few specific examples. Ms. Foglia explained to us the regulation of body temperature. When the body's temperature increases the brain sends nerve signals through the body causing us to sweat and dilates the surface blood vessels. Also she explained the body's response to a decrease in body temperature. In this case the body sends nerve signals through the body causing us to shiver and constrict the surface blood vessels.

We also went over negative feedback in the endocrine system. We went over blood osmolarity, which is the measurement of the concentration of solutes dissolved in the water. Blood osmolarity affects blood pressure. When increased blood pressure increases. When blood pressure and blood osmolarity are increased the pituitary gland releases anti-diuretic hormones (decrease the need to urinate). This increases water reabsorption and increases thirst, bringing blood pressure back to its set point. When blood osmolarity and blood pressure are low JuxtaGlomerular Apparatus releases renin which activates angiotensinogen. Angiotensinogen is an inactive protein but in this process is activated, becoming angiotensin (zymogen). The angiotensin triggers the aldosterone which increases the absorption of salt and water in the kidneys.

This occurs not only in our bodies but in our everyday lives. We too use negative feedback, when criticized we change to make ourselves better.

Tomorrow's sherpa will be Mia =]

The Nervous System:

2007-12-04T14:16:00.000-08:00

Hey period 8 and 9, this is what Tuesday's lecture was on:

Ok so The Nervous System! Err, Umm, What To Say.......Yea

So why do animals need a nervous system and what characterisitcs are needed in a nervous system. A Nervous system needs to be -Fast!, -Accurate! and needs to -Reset Quickly!.

Ok, so the nervous system has cells called neurons. They happen to be the most specialized cells in animals. They can be extremely large, for example like the Blue Whale and Giraffe (10-30 Meters and 5 Meters) or Small, for example like in humans (1-2 meters depending on the size of the person). Ok so in the Neuron, which is a nerve cell and it has many parts to it. There are Dendrites, which are branch like structures that receive signals. Then there is the cell body which leads to the axon. The axon furthers the signal to the synapse where it leaves the neuron and keeps traveling. Ok, so the neuron fits its function well, as their are many possible entries for the signal to travel to, so theres a possibility that more information can be gathered. But, theres only one path out out neuron.

So, a neuron has many protein channels. Once one opens, the rest open with succession, an "all or nothing response". So the cell is surrounded by a "sea" of charged ions. There are anions, which a concentrated on the inside of the cell and are negative, for example Chlorine and Amino Acids, and there are Cations, which are concentrated in the extracellular fluid and are positive, for example Potassium and Sodium. The potassium channel happens to leak some potassium, which is normal, but this is an extremely slow process. Cells actually have voltage and this could be measured. An unstimultated neuron at its resting potential has a voltage of -70mV or mini-volts. So their happen to be opposite charges on the opposite sides of the cell membrance which is polarized. The inside is negative while the outside is positive. This means there is a Charge Gradient! Energy

So how does a nerve impulse travel? Ok, first the nerve is stimulated. Once the threshold potential is rached, the Sodium channels in the membrane open up and the Sodium ions diffuse into the cell. At this point the charges on the neuron are reversed. It becomes positive on the inside and negative on the outside. This means the cell becomes Depolarized. So how does the signal keep traveling down? Well remember how I said if one Sodium channel opens up, the rest open up in succession, yea so that happens in a line. The Sodium ions continue to diffuse into the cell. Finally the wave that mmoves down the neuron is called the action potential or basically a nerve impulse. (The rest of the Dominoes fall! Yay!)

Ok, hopefully you got that. Now how does that 2nd wave travel down the neuron. Well it has to re-set itself. So basically the Potassium channels open up, but much slower than the Sodium channels. Then the Potassium ions diffuse out of the cell. Therefore the charges reverse back to the original state, negative on the inside and positive on the outside. (Setting up the dominoes! Quickly!) So the signal moves down one and in one direction only. The flow of Potassium out of the cell stops the activation of Sodium channels in the wrong direction. (Ready Again!)

Ok so thats basically it! Allright thats it, Thanks guys, Umm the Sherpa for Wednesday is "I Dont Know" Ok then, Night

-Liver

Regulating the Internal Environment

2007-12-02T14:48:00.000-08:00

Well guys and ms.Folglia i would first like to apoligize for writing this blog so late even though it was supposed to be up on friday. So SORRY :( .

ALRIGHTY THEN. Where do we start? OH yeah Regulating the internal environment.

Well first of all we have to know what HOMEOSTASIS means and basically all homeostasis is, is maintaina balance in the internal environment. It is keeping the internal environment ballanced and regulated. Some examples of

The Cell Membrane

2007-11-27T15:13:00.000-08:00

The Cell Membrane

The cell membrane is the barrier that separates the inside of the cell from the outside. The cell membrane is made up of phospholipids,proteins, and other macromolecules. The phosopholipids make up a bilayer. It contains hydrophilic and hydrophobic molecules. The proteins in the cell membrane are located within the phospholipid bilayer. These proteins determine certain funtctions of the cell membrane. There are three types of proteins.

Peripheral Integral Transmembrane

-loosely bound -penetrate lipid bilayer -transport proteins

-on the surface of the cell -across entire membrane -channels,permeases

-identity markers

Nonpolar amino acids - hyrophobic

polar amino acids - hydrophilic

Antigens are markers of a cell and can tell cells apart. It rejects foreign cells, and lets certain cells enter.

Diffusion - is the movement from high concentration to low ( an easy way of thining of it would be H comes before L in the alphabet). Fats and other lipids can get through the phospholipid bilayer directly by diffusion, other larger molecules such as starch can not get into the cell directly.

Facilitated Diffusion (facilitated=with help, open channel=fast transport). Diffusion of hydrophilic molecules. From High to Low.

Active Transport- diffsuion against concentration. Low to High. ATP is needed.

Osmosis = diffusion of water. High to Low. The survival rate of a cell counts on a balance of water loss and uptake. Determined by amount of solute, and water.

Hypertonic=more solute, and less water.EX-shellfish, plant cells

Hypotonic=less solute, and more water. EX- paramecium

Isotonic=equal solute, and equal water. EX-blood cells in blood

Theme 8: SCIENCE, TECHNOLOGY & SOCIETY

2007-11-21T09:37:00.000-08:00

Theme 8: SCIENCE, TECHNOLOGY & SOCIETY
Explanation: Scientific research often leads to technological advances that can have positive and/or negative impacts upon society as a whole.
Clarification: You would post here examples of how technological innovations have helped advance science whil ethose technolical accomplishments may have also had either beneficial or deleterious impacts on human society.

Theme 7: INTERDEPENDENCE IN NATURE

2007-11-21T09:34:00.000-08:00

Theme 7: INTERDEPENDENCE IN NATURE
Explanation: Living organisms rarely exist alone in nature.
Clarification: You would post here examples of how organisms must interact together to live successfully.

Theme 6: REGULATION

2007-11-21T09:26:00.000-08:00

Theme 6: REGULATION
Explanation: Everything from cells to organisms to ecosystems is in a state of dynamic balance that must be controlled by positive or negative feedback mechanisms.
Clarification: You would post here examples of how a dynamic equilibrium is maintained at different levels of life, from homesostatic control of cellular and body conditions to maintenance of population levels in ecosystems.

Theme 5: RELATIONSHIP OF STRUCTURE & FUNCTION

2007-11-21T09:13:00.000-08:00

Theme 5: RELATIONSHIP OF STRUCTURE & FUNCTION
Explanation: The structural levels from molecules to organisms ensure successful functioning in all living organisms and living systems.
Clarification: You would post here examples of structure-function relationships in living organisms. How specific molecules, organelles, cells, tissues, organs, and body structures are structured to support the functions that they perform. (Don't forget plants!)

Theme 4: CONTINUITY & CHANGE

2007-11-21T09:07:00.000-08:00

Theme 4: CONTINUITY & CHANGE
Explanation: All species tend to maintain themselves from generation to generation using the same genetic code. However, there are genetic mechanisms that lead to change over time, or evolution.
Clarification: You would post here examples of how organisms reproduce while maintaining the same genetic information from generation to generation AND also examples of how organisms reproduce while accumulating changes to their genetic information from generation to generation.

Theme 3: ENERGY TRANSFER

2007-11-21T09:04:00.000-08:00

Theme 3: ENERGY TRANSFER
Description: Energy is the capacity to do work. All living organisms are active (living) because of their abilities to link energy reactions to the biochemical reactions that take place within their cells.
Clarification: You would post here examples of how organisms are able to capture energy and utilize it to do the work that supports life.

Theme 2: EVOLUTION

2007-11-21T08:58:00.000-08:00

Theme 2: EVOLUTION
Description: Biological change of organisms that occurs over time. Which is driven by the process of natural selection. Evolution accounts for the diversity of life on Earth.
Clarification: You would post here examples of evolutionary change in populations of organisms that we have been able to observe or have evidence of.

Theme 1: SCIENCE AS A PROCESS

2007-11-21T08:53:00.000-08:00

SCIENCE AS A PROCESS
Description: Science is a way of knowing. It can involve a discovery process using inductive reasoning, or it can be a process of hypothesis testing.
Clarification: You would post here examples of how the scientific process has been used to develop our knowledge about how the biological world works.

A Tour of the Cell

2007-11-19T15:10:00.000-08:00

Hey Period 8+9, this was what Monday's lecture was about:

The are different types of cells. There are Prokaryote Cells and Eukaryote Cells which are 2 different domains. The Prokaryotic Bacteria Domain, the cells don't have Membrane Bound organelles and are not specialized. They old consist of Ribosomes and a Cell Membrane/Wall. With Eukarote Domain, there are 2 main cells, the Animal Cells (Of the Animal Kingdom) and the Plant cells (Of the Plant Kingdom). Both these cells have their differences.

Only Plants have a large Central Vacuole, Chloroplasts (for photosynthesis), Centrioles and a Cell Wall.

Now what makes Prokaryotes and Eukaryotes different you ask? Well the answer is organelles. Eukaryotic cells (yes, both plant and animal) have specialized structures withspecialized functions for example cillia or flagella for locomotion. Another reason is that they have "Containers." The cell has compartments in which different local environments are created for example separate pH's. They also have distinct and incompatible functions for example the lysosomes which has its own digestive enzymes. If the lysosome didnt have its own compartment the whole cell would be digested. Also membranes are the sites of Chemical Reactions. There are a unique combination of lipids and proteins and embedded enzymes and reaction centers for example the Choroplasts and Mitochondria where reactions occur.

Now how do cells "make their living"? What jobs do they have to do?

Well their first job is to build proteins. This is because PROTEINS CONTROL EVERYTHING! All the cell functions are controlled by proteins. Their second job is to make energy. This is in order to continue on in daily life and for growth to occur. The third and final job is for the creation of more cells. This gives the opportunity of growth, reproduction and most importantly repair.
Now it is important to study the production of proteins because they are important macromolecules. DNA (Deoxyribnucleic Acid) is the code for creating proteins. Proteins have the job of acting as an enzyme (most enzymes are proteins). Life cannot be run without the influence of proteins. Now in building proteins such organelles as the nucleus, ribosomes, the endoplasmic reticulu, the golgi apparatus and vesicles are involved. Now in the nulcues there obviously is DNA. Proteins go down an assembly line starting with the Nucleus (DNA),onward to the Ribosomes, then to the Endoplasmic Reticulum, the to the Golgi Apparatus and finally to the vesicles.

Now in creating proteins DNA cannot leave the cell, therfore it must make copies of itself inorder to leave and create the proteins that will later have specific functions. There is also no diffusion in the membranes because they are made of lipids. So the RNA travels through out the ER where the ribosomes dwell and read the code to create a polypeptide. Then they travel farther in the ER until they get to the end and bud off in a vesicle to the Golgi Apparatus. There the polypeptide finally folds istelf and travels farther until it is a completed and finsished protein on its way to do its job. An example of this would be the creation of Insulin and the Beta Cells of the Pancreas. If this producton stopped within 3 days a human would be dead.

The next important objective is to create energy in a cell. Once again making energy allows for daily life to continue and for growth to keep occuring. Now cells need lots of energy for power. In order to make energy, cells need to take in food and digest it, take in oxygen and therefore create ATP! (Adenosine triphosphate). Lastly the removal of waste is also needed. On to the Lysosomes!

Now the lysosomes are known as the "little stomach" of the cell (which is a misnomer because in humans digestion takes place mostly in the intestines). The lysosomes digest the macromolecules. The lysosomes are also the "clean up crew" of the cell because they break down the old and damaged organelles. Where Old Organelles go to die! Lysosomes are composed of vesicles with specialized digestive enzymes. Lysosomal Enzymes work best at a pH of about 4.8-5.0. The lysosome creates its own pH levels. It is more acidic than the rest of the cell. This is because the proetins in the lysosome membrane pump up H+ ions from the cytosol into the lysosome. The Cytoplasm happens to be all the contents of the cell while the cytosol is the "Gunk" between the organelles. Now, because the enzymes are sensitve to certain pH's they have to custom make their own and why is that? Well, enzymes are proteins aren't they? So what do we know about them? Yep, pH affects the protein structure and they can denature themselves. Now this is an adaption because if the digestive enzymes were to leak into the cytosol the cell would literally digest itself! But sometimes it is necessary for cells to die and be re-absorbed. Lysosomes can be used to kill cells when it is necessary. Sometimes proper development in an organism requires this process. Apoptosis, an "auto-destruct" process the lysosomes break open and kill the cell. For example the tail of a tadpole gets reabosorbed when it turns into a frog in order to grow legs. Or the loss of webbing between a fetuses fingers during its development (although there are some diseases such as Syndactyly in which the fingers are not dissolved and the fingers stay fused)
and the self-destruction of a cancerous cell in an organisms body (Obviously this doesnt always happen).

But as always, things do go wrong. The diseases of Lysosomes are most often fatal. This occurs when the digestive enzymes in the lysosomes fail to function correctly. What happens is that biomolecules are absorbed but not digested as they cant be. Therefore the lysosomes fill up with lots of undigested materials in which the cell grows larger and larger until the cell is disrupted along with the ogran functions. The are more than 40 known types of lysosomal storage diseases. For example Tay-Sachs disease in which the brain cells build up a number of undigested fats.

Well thats it for Monday's lecture. Tuesday's Sherpa will be Mark, Have Fun and Enjoy! :-) Night

-Liver

Nucleic Acids

2007-11-18T17:56:00.000-08:00

A Nucleic acids function is to store & transmit hereditary information. Examples of Nucleic Acids are RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). Nucleic Acids are made out of monomers. There are long chains of monomers that you can add repeating units to. These Monomers are Nucleotides. A nucleotide consists of three parts. A nitrogen base (C-N ring) a pentose sugar (ribose in RND deoxyribose in DNA). The deoxy in deoxyribose means the sugar is missing a oxygen. The third part is a phosphate group.

RNA & DNA
RNA is a single nucleotide chain in a single helix. DNA is a double nucleotide chain consisting of Nitrogen bases bond in pairs across the chains. DNA is spiraled in a double helix. This was first proposed in 1953 by James Watson and Francis Crick.

Types of Nucleotides
THere are two types of nucleotides. THis is because of different nitrogen bases. There are purines which have bigger bases and pyrimidines which have smaller bases. Purines have a double ring nitrogen base. They consist of adenin (A) and Guanine (G).

Pyrimidines have a single ring Nitrogen Base. They conisist of cytosine(C), thymine (T) and uracil (U).

Nucleic Polymers
Nucleic polymers are the backbone of DNA. They are made of sugars and PO4. THE polymers conisist of phosphodiester bonds. These bonds are new bases added to teh sugar of a previous base. The polymer grows in one direction. Nitrogen bases hang out the sugar-phosphate backbone.

Pairing of Nucleotides
Nucleotides bond between DNA strands. These bonds are Hydrogen bonds. They are purines H bonded to pyrimidines. A::T (2 hydrogen bonds) and G::C (3 hydrogen bonds). These matchign bases are important for replication. THis way a T is always bonded to a A and vis versa. The same is with G and C. SInce the bonds are to the same purine or pyramidine there is no confusion when replicating. This way exact copies are made.

Information Polymers
They are a series of bases encoding information. An example would be words ina book. The Stored information is passed from the parent to the child. Because of thisDNA needs to be copied accurately. The information copied is your genes. This is important because if you the parent survived then your offspring have a greater chance of survivng with your genes.

DNA Molecule
The Dna Molecule is a double helix. The hydrogen bonds between the 2 bases join the strands. A::T C::G These bonds are important becaus ethey are easy to break and put back together for replication. Copying DNA is caklled replication. The 2 strands of DNA helixs are complementary. With one strand you can build the other and with one strand you can rebuild the whole molecule. A cell copies DNA during cell reproduction (mitosis) and gamete production (meiosis).

Well thats nucleic acids. The next shurpa will be jesse. Enjoy!

Proteins

2007-11-15T07:32:00.000-08:00

Proteins are multipurpose molecules. They are the most structurally and functionally diverse group of biomolecules. Proteins are also involved in almost everything. Proteins can act as enzymes such as pepsin and polymerase. Pepsin is the enzyme found in our stomachs which is used in digestion. Proteins such as keratin and collagen form structure, such as a bird's beak or hair. Proteins also take part in carrying and transporting information, and give defense with antibodies. Proteins are also used in contraction, signaling, and storage.

Structure

Proteins are made of twenty different amino acids. Amino acids are monomers. Polypeptides are polymers which are made from chain of amino acids bonded together. Proteins can be one or more polypeptide chains folded and bonded together.

Rubisco is a very important polypeptide because it allows plants to go through photosynthesis.

Amino acids have a central carbon with an amino group and a carboxyl group (acid) as well as a sidechain known as an group which confers unique chemical properties of the amino acid.

Nonpolar amino acids are hydrophobic. These are nonpolar and hydrophobic because they are made up of a lot of carbons which are nonpolar and hydrophobic, and so they want to push away from water. Polar amino acids are polar or charged and hydrophilic, meaning that they mix well with water.

The function of proteins depends on the structure. Proteins are twisted, folded, and coiled into a unique shape. Hemoglobin is a protein with both alpha and beta proteins which carry oxygen in the blood.

Primary Structure > Order of Amino Acids

Seconday Structure > "Local Folding"- folding long short sections of polypeptides

Has alpha helix and beta pleated sheet. There are hydrogen bonds against adjacent proteins.

Tertiary Structure > "Whole Molecule Folding" - determined by interactions between R groups. Tertiary structure has hydrophobic interactions and is anchored by disulfide bridges.

Quarternary Structure > more than one polypeptide chain joined together

Denaturing a Protein

This is unfolding a protein by disrupting tertiary structure. Disrupting the pH, salt, or temperature of a protein disruptsH bonds, ionic bonds and disulfide bridges, which destroys functionality. Some proteins can return to their functional shape after denaturation, but many can not.

2007-11-11T17:15:00.000-08:00

Heyy, period 8 and 9!
Today we learned all about Carbohydrates. The name "carbohydrate" means a "hydrate of carbon.” Carbohydrates always have a 1:2:1 ratio of carbon, hydrogen, and oxygen.
The general formula of carbohydrate Cx(H2O)y - x and y may or may not be equal and range in value from 3 to 12 or more. For example glucose is: C6(H2O)6 or is more commonly written, C6H12O6.The chemistry of carbohydrates most closely resembles that of alcohol, aldehyde, and ketone functional groups. The chemistry of carbohydrates is complicated by the fact that there is a functional group (alcohol) on almost every carbon. In addition, the carbohydrate may exist in either a straight chain or a ring structure.
A major part of the carbon cycle occurs as carbon dioxide is converted to carbohydrates through photosynthesis. Carbohydrates are utilized by animals and humans in metabolism to produce energy and other compounds.

Carbohydrate Functions:
Carbohydrates are initially synthesized in plants from a complex series of reactions involving photosynthesis.
-Store energy in the form of starch (photosynthesis in plants) or glycogen (in animals and humans).
-Provide energy through metabolism pathways and cycles.
-Supply carbon for synthesis of other compounds.
-Form structural components in cells and tissues.

Photosynthesis:

is a complex series of reactions carried out by algae, phytoplankton, and the leaves in plants, which utilize the energy from the sun. The simplified version of this chemical reaction is to utilize carbon dioxide molecules from the air and water molecules and the energy from the sun to produce a simple sugar such as glucose and oxygen molecules as a by product. The simple sugars are then converted into other molecules such as starch, fats, proteins, enzymes, and DNA/RNA i.e. all of the other molecules in living plants. All of the "matter/stuff" of a plant ultimately is produced as a result of this photosynthesis reaction.

Metabolism:
Metabolism occurs in animals and humans after the ingestion of organic plant or animal foods. In the cells a series of complex reactions occurs with oxygen to convert for example glucose sugar into the products of carbon dioxide and water and ENERGY. This reaction is also carried out by bacteria in the decomposition/decay of waste materials on land and in the water.
Combustion occurs when any organic material is reacted in the presence of oxygen to give off the products of carbon dioxide and water and ENERGY. The organic material can be any fossil fuel such as natural gas oil, or coal. Other organic materials that combust are wood, paper, plastics, and cloth.

The whole purpose of both processes is to convert chemical energy into other forms of energy such as heat.

The monomers of carbohydrates are called monosaccharides and are also called simple sugars. They are usually ring-like and are composed of five or six carbons. They are either a polyhydroxy aldehyde or a polyhydroxy ketone, which means they have more than one hydroxide group (-OH) and one carbonyl group (C=O). Some popular monosaccharides are glucose, fructose, and galactose.However, some very important carbohydrates are composed of thousands of monomers and are called polysaccharides. Here are the main important polysaccharides:- starch: Plants store their energy as starch using photosynthesis. We eat plants, breaking down the starch into its monomers and putting it to good use.- cellulose: The cell walls around plants are composed of cellulose. Cellulose is a very important structural component of plants and it's what makes them snap when you rip them apart. Err, I mean - they provide support for the plant.- glycogen: Animals store energy as glycogen. It's stored in the liver.

A carbonyl group is a functional group composed of a carbon atom double bonded to an oxygen atom : C=O.

An aldehyde is an organic compound containing a terminal carbonyl group. This functional group which consists of a carbon atom which is bonded to a hydrogen atom and double bonded to an oxygen atom (chemical formula O=CH-), is called the aldehyde group.

A ketone (pronounced as key tone) is either the functionalgroup characterized by a carbonyl group (O=C) linked to two other crbon atoms or a chemical compound that contains this functional group. A ketone can be generally represented by the formula:
R1(CO)R2.

Cellulose:
The major component in the rigid cell walls in plants is cellulose. Cellulose is a linear polysaccharide polymer with many glucose monosaccharide units. The acetal linkage is beta which makes it different from starch. This peculiar difference in acetal linkages results in a major difference in digestibility in humans. Humans are unable to digest cellulose because the appropriate enzymes to breakdown the beta acetal linkages are lacking. Indigestible cellulose is the fiber which aids in the smooth working of the intestinal tract.
Animals such as cows, horses, sheep, goats, and termites have symbiotic bacteria in the intestinal tract. These symbiotic bacteria possess the necessary enzymes to digest cellulose in the GI tract. They have the required enzymes for the breakdown or hydrolysis of the cellulose; the animals do not, not even termites, have the correct enzymes. No vertebrate can digest cellulose directly.

Compare Cellulose and Starch Structures:
Cellulose: Beta glucose is the monomer unit in cellulose. As a result of the bond angles in the beta acetal linkage, cellulose is mostly a linear chain.
Starch: Alpha glucose is the monomer unit in starch. As a result of the bond angles in the alpha acetal linkage, starch-amylose actually forms a spiral much like a coiled spring.

Tommorows sherpa is.. Kim

Later Class!

2007-11-10T16:15:00.000-08:00

Building Blocks of Life

Carbohydrates- function for short-term energy storage
Lipids-function for long-term energy storage, insulate, and are used in the construction of cell membranes.
Proteins- function to build body structures and regulate metabolism
Nucleic Acids – compose all of your genetic material, including DNA and RNA.

All life is built on carbon. There are four major groups of carbon compounds that are important carbohydrates, lipids, proteins, and nucleic acids. A carbon atom is made up of four covalent bonds, and is a stable. Hydrocarbons are stable, and non-polar. As well as hydrophobic which is hydro = water, and phobic = fearful. This means the molecules are not attracted, and are not as close making it a gas. The writing on this picture is really annoying, but I couldn’t find one without it.

Isomers- molecules with the same formula but are different in shape. Each of these diagrams has four carbons, but different chemical properties and biological functions. The structure does have an affect by creating different functions. For example medicine in L-version is active, and D-version is not. So structure does have a significant role.

-Organic compounds with OH are alcohols.
-C=O at end of molecule is an aldehyde, and C=O in the middle is a ketone.
-COOH is an acid.
-N attached to 2 H is amines it acts as the base.
-SH is thios, and it stabilizes the structure of proteins.
-P bonded to 4 O is highly reactive and transfers energy between ATP and GTP.

Monomers link together to create polymers. In synthesis water is taken out, and in digestion water is used to break down polymers.

http://www.youtube.com/watch?v=fHRhEF91Zh8

The Chemistry of Life

2007-11-07T16:12:00.000-08:00

Chemistry is the foundation of biology. About twenty-five chemicals are necessary for life, and only four create about 96 % of living matter. Those four elements are carbon, oxygen, hydrogen, and nitrogen. We cant live without COHN.

Bonding properties of atoms depend on the number of electrons in the valence shell. Oxygen is the most electronegative element on the periodic table, it is the most reactive. Covalent bonds are strong bonds because the electrons are shared between the atoms. They are very stable. There are polar and nonpolar covalent bonds. In polar covalent bonds, electrons are shared unequally, such as in water.

Hydrogen bonds, ionic bonds, hydrophobic and hydrophilic interactions, and van der Waals forces are examples of weak bonds. Hydrogen bonding can happen anywhere an -OH exists in a larger molecule. It occurs when polar water creates molecular interactions.

All life occurs in water, whether under the sea or inside the cell. Without water life could not exist. Water is very unique. It is cohesive, water molecules are attracted to each other, and adhesive, water molecules stick to other things. These are the reasons that water can reach the top of trees. Its a good solvent, most things can dissolve in water. Hydrophilic substances, which are polar, dissolve in water and hydrophobic substances, which are nonpolar, do not. It has lower density as a solid, which is very rare, actually nothing else has that property. The fact that water does this is not only an amazing phenomenon, but it enables life on Earth to continue. If ice sank, all bodies of water would completely freeze over time and there would not be enough time in the summer for it to thaw, therefore life could not exist. It has a very high specific heat, its very resistant to temperature change, and it takes a lot of energy to heat and cool water. Water moderates temperatures on Earth. And finally it has a high heat of vaporization. When water evaporates off of your skin it cools you off, which is why we sweat and why animals pant when they’re hot.

Water ionizes, H+ splits off leaving -OH, if they’re equal then the solution is neutral. If H+ is greater, the solution in acidic and if -OH is greater, the solution is basic. The pH scale shows how acidic or basic a solution is, 0 is most acidic, 7 is neutral, and 14 is the most basic. There are buffers to help regulate pH levels. The pH of a molecule affects its shape which affects its function. These buffers donate or absorb H+ when it falls or rises to maintain a level of about 7.

Tomorrows sherpa will be Kerrie.

Animal Behavior (cont...)

2007-11-01T17:13:00.000-07:00

today we learned more about animal behaviors. Migration is shown not only in birds but in insects as well. We also learned an interesting fact about migration in that birds navigate their migrations by means of the sun, stars, and magnetic waves. Imprinting shows that learning that occurs during a critical period forms social attachments. Konrad Lorenz studied this with geese. His work has a movie based on it called Fly Away Home here is a clip.

http://youtube.com/watch?v=FXUR0-_azSU

The critical period is the period for the greatest potential learning to take place. Learned behaviors are an association of a stimulus in the environment to a behavior. there are two types of conditioning operant and classical to enforce learned behaviors. Operant condition uses trial and error learning, and association of a behavior with either a punishment or reward. Classical conditioning however assosiates a neutral stimulus with a signifigant stimulus. This type of conditioning is shown in Pavlovs Dogs where pavlov tested salivation in dogs to be associated with a bell by ringing a bell prior to presenting them with food. Habituation is the eventual loss of response to a stimulus once the stimulus happens enough times that the result can be anticipated.
Language is used in all different animals in all different ways in humans we speak, whereas in honey bees they dance to communicate in all different patterns. Some animals communicate via song such as birds and insect some are learned, and some innate. Agnostic behaviors appear violent or hostile but really no harm is generally done, but it is more a test of manhood. Altruistic behavior is when an individual reduces their own fitness for the benefit of the group. Pheromes are chemical signals such as smell used to warn of danger or trigger sex hormones.

Ethology and Isopods

2007-10-30T18:54:00.000-07:00

Ethology
-- The study of behavior in animals

Ethology is a combination of laboratory and field science

Behavior - the way in which a person, organism, or group responds to a specific set

of conditions

Innate - relating to qualities that a person or animal is born with. coming directly from

the mind rather than being acquired by experience or external sources

Automatic, fixed behavior. Despite difference in habitat, all individuals exhibit the

same behavior usually triggered by a stimulus.

Fixed Action Patterns (FAP)- Sequence of behaviors essentially unchangeable and

usually conducted to completion once started

Sign Stimulus - a release that triggers FAP

Learned - acquired information or skills through experience.

Modified from experience. Triggered by an experience and it varies.

(Behavior is a part of phenotype)

Pioneers

Karl Von Frisch

He studied the senses of bees, identified their mechanisms of communication and showed their sensitivity to ultraviolet and polarized light. His work was based on the study of the sensory perceptions of the honey bee and was one of the first who translated the meaning of the waggle dance The theory was disputed by other scientists and greeted with skepticism at the time. Only recently was it definitively proved to be an accurate theoretical analysis

Waggle Dance - figure-eight dance of the honeybee dance demonstrates the will to share with their hive mates the information about the direction and distance to patches of flowers yielding nectar or pollen, or both, and to water sources. Thus the waggle dance is a mechanism whereby successful foragers can recruit other bees in their colony to good locations for collecting various resources.

Niko Tinbergen

Well known for work with birds as well as developing the four questions to be asked when observing the behavior of an animal/species:

Proximate Questions

1. What are the stimuli that elicit the response, and how has it been modified by recent learning?

2. How does the behaviour change with age, and what early experiences are necessary for the behaviour to be shown?

Ultimate Mechanisms

3. How does the behaviour compare with similar behaviour in related species, and how might it have arisen through the process of phylogeny?

4. How does the behaviour impact on the animal's chances of survival and reproduction?

Konrad Lorenz

Lorenz studied instinctive behavior in animals, especially in grey lag geese and jackdaws. Working with geese, he rediscovered the principle of imprinting in the behavior of nidifugous birds.

One result of these studies was that Lorenz "realised that an overpowering increase in the drives of feeding as well as of copulation and a waning of more differentiated social instincts is characteristic of very many domestic animals."
Imprinting - a form of rapid learning very early in an animal's social development that results in strong behavioral patterns of attraction to members of its own species, especially parents.
Imprinting was first described by Konrad Lorenz in 1937 when he trained young ducks and geese to follow him and regard him as their mother.

Isopods:

Iso is Greek for "similar or equal." Pod means "foot." Both sides have the same number of legs.

Arthropod: One of the most diverse orders of crustaceans, with many species living in all environments, but are most common in shallow marine waters. Unlike most crustaceans, isopods are successful on land, although their greatest diversity remains in the deep sea.

Appearance: Isopods have three main body parts; the head, thorax, and the abdomen. They have one prominent pair of antennae which are used to search and taste and smell food and have a second pair which are not seen. and seven pairs of legs. Isopods have seven separate appendages on the thorax and paired appendages at the end of the abdomen called uropods. Isopods vary in colour from dark gray to white, with and without pattern.

Behavior: Some species roll up into a ball when disturbed. Eggs (up to 100) are held in broad pouch on female. Juveniles look like adults and are soon liberated from pouch. Molting is in two stages. First the back half molts, then two to three days later, the front half molts. Coloration of both halves may be different at this time. Many species are fast walkers, but can be easily observed when held in the palm of the hand.

Habitat: Isopods breathe with gills, so they are restricted to areas with high humidity, under

rocks or logs, in leaf litter or in crevices. Some species are nocturnal.

Some Videos:

Isopods:

http://youtube.com/watch?v=32Q7BRBiscQ

Waggle Dance:

http://youtube.com/watch?v=-7ijI-g4jHg

Tomorrows Sherpa is Marc

Earth's biomes

2007-10-29T12:38:00.000-07:00

Earth's biomes consist of tropical forest, savanna, desert, polar and high mountain ice, chaparral, temperate grassland, temperate deciduous forest, coniferous forest, and tundra.

Environmental Factors

There are different factors effecting each environment. These factors are both biotic ( caused by living components such as animals and plants) and abiotic (non-living chemical and physical factors caused by temperature, light, water, and nutrients.)

Marine : This is the largest biome in the world and covers approximately 70% of the earth. There are three zones in the Marine Biome. These are the intertidal, coral reef, and benthos zones. The benthos is the only biome not built on sunlight.

Tropical Rainforest: Tropical rainforests are located around the equator, have much precipitation, are always warm and have many plants and animals. Also, tropical rainforests have thin soil.

Savanna: Savannas are also located around the equator. Their precipitation is seasonal (having both a dry season and a wet season), temperature is always warm. Savannas are fire-adapted, have drought tolerated plants, the animals are herbivores, and savannas have fertile soil. There is less moisture, and a lower biodiversity than in the rainforest.

Desert: Deserts are located at around 30* N & S latitude. The temperature varies daily and seasonally between extreme heat and cold. Deserts have sparse vegetation and animals, and are drought tolerant. Organisms living in deserts are cacti, reptiles, insects, rodents and birds. Deserts have high energy and no moisture.

Temperate Grassland: Temperate Grasslands are located at mid-latitudes and mid-continent. Precipitation is seasonal (there is both a dry and wet season), the temperature is hot summers and cold winters. Temperate grassland has prairie grasses, is fire adapted, has drought tolerant plants, many herbivores, and deep fertile soil. It has less insolation and its seasons restrict biodiversity.

Temperate Deciduous Forest: Located mid-latitude and in the northern hemisphere. They have adequate precipitation (summer rains and winter snow). The temperature is moderate warm in the summer and cool in the winter. Temperate Deciduous forests contain many mammals, insects, deciduous trees and fertile soils. These areas are very diverse.

Coniferous Forest (Taiga): These are located at high latitudes and in the northern hemisphere. Precipitation is adequate to dry and temperature is cool year round. Many conifers are present, along with a diversity of mammals, birds, and insects. The trees have needles leaves.

Arctic Tundra: Located in the arctic at high latitudes (northern hemisphere). It is a very dry region and is cold year round. There is permafrost, lichens & mosses, migrating animals, and resident herbivores. Herds of animals move across tundras during the season to get to another community. The tundra has low energy and water and can not support a bid biodiversity.

Alpine Tundra: This tundra is located at high elevations and at all latitudes. It is a dry region and is cold all year round. Characteristics also include permafrost, lichens & mosses, grasses, and has migrating animals and resident herbivores. There is low moisture.

Earth and What is Happening

Impact of ecology as a science: Ecology provides a scientific context for evaluating environmental issues.

Rachel Carson published a book Silent Spring in 1962 which warned of pesticides such as DDT and their effects on non-target organisms. DDT is a problem, because although it has no harmful effects on humans, it does hurt other organisms such as birds. Once DDT is in the food chain it stays forever. This is a picture of what DDT can do to birds eggs:

Barry Commoners Laws of Ecology:

>Everything is connected to everything else.

>Everything must go somewhere

>there is no such place as "away"

>Nature knows best.

>There is no such thing as a free lunch.

These are Barry Commoner's Laws of Ununtended Consequence. Pretty much he means hat, garbage is never gone because it has to go somewhere in the ecosystem when thrown away. Also everything has an effect on the ecosystem, whether it be a benefit or not.

Acid Precipitation:

Acid precipitation puts nitrogen oxides and sulfur dioxide in the air. The causes of acid precipitation is power plants, industry, and transportation because they burn fuels such as coal. Wind brings acid rain from certain regions to others, because in areas with many factories, tall pipes are made to "get rid of the bad air" and then the wind blows that to other areas. Many things have been ruined by acid, such as statues. Acid rain leeches minerals from the environment causing both ecological and economic damage.

Biomagnification:

>Energy Pyramid: tocins concentrate as they move up the food chain. THere have been ecological problems occurring with where manufacturing companies dump their waste. General Electric, for example, was once manufacturing on the Hudson River and dropped PCBs in the sediment near where striped bass reproduce. This causes the striped bass to have high levels of PCBs.

Global Warming:

There is a direct relationship between the increasement of carbon dioxide and temperature which can support the belief of Global Warming. Global warming is believed to be anthropogenic ( human caused), and raises the temperature which in turn is increasing the rate at which the polar ice caps are melting and raising the coastline which can and will eventually destroy major cities which are situated on coastlines. Some believe that global warming is not a problem, and others acknowledge it but do nothing because of economic factors. Many wealthy politicians have ties in the oil industry and if they promoted burning less fossil fuels then they would also lose money.

During warmer seasons CO2 levels in the atmosphere are lower because plants are photosynthesizing and turning CO2 into glucose. One way to help the environment would be to plant more plants, because it would help decrease CO2 levels more.

Ozone Depletion:

The ozone layer protects from UV rays from the sun and also contains CFCs which are coolants. Over the years, the O3 layer in the ozone has been breaking down into O2. There has been the biggest decrease in ozone over antarctica. Several precautions and changes have been taken to help decrease the depletion, and they have proven successful. There is both bad ozone and good ozone. Smog is bad ozone which is caused by pollution.

Deforestation:

Humans are cutting down forests to build houses, or to have more farmland, and grazing land for animals. Doing so destroys the habitat, which decreases biodiversity and also accounts for a loss of stability in the environment.Cutting down the trees, decreases the energy supple for the herbivores which in turn decreases the available energy for predators, and then the community cannot support the top predator, who will then die off.

Loss of Diversity:

There are three levels of biodiversity. The first level is genetic diversity and causes inbreeding within shrinking populations. The second level is community diversity which is a mix of species, and the environment can not support as much with loss of diversity. The third level is ecosystem diversity which accounts for different habitats across landscape. All biodiversity is decreased by human acticity.

Fragmented Habitats make for loss of habitat, loss of food resources for higher levels on the food chain, loss of biodiversity, and loss of stability.

http://www.youtube.com/watch?v=EDIP71Lviys

http://www.youtube.com/watch?v=kMckwcwvb50

Tomorrow's Sherpa is Shannah =]

Community Ecology: Part III

2007-10-25T17:10:00.000-07:00

HEY HEY..... PERIODS 8 & 9, LISTEN UP...

Today's lesson was on ECOLOGICAL SUCCESSION... and it's outcomes.

What is ecological succession??? Well it is a "sequence of community changes."

Yeah... but what does that mean . It means that the ecology of a community changes to maintain the balance and success. It is the transition in species composition over time (may be years or even decades). Species composition refers to the contribution of plant species in a certain area. Most of the time this is caused by a disturbance in the area.

There are two types of ecological succession: Primary succession and Secondary succession.

Primary Succession
Primary Succession begins on plain lifeless land without soil...
What happens next...

1. Bacteria moves in and by definition of what they do, they turn the dirt into soil. Land with nutrient and land able to support some sort of living matter besides bacteria.

2. Lichen and mosses move in and begin to grow. They use the nutrient from the soil to support themselves.
3. Grasses are then able to move in by the seeds that come in from adjacent communities.

Community Ecology: Part DUEX.

2007-10-24T17:07:00.000-07:00

predation drives evolution:

basically - as predators become better at locating and subduing pray, their pray over time develops adaptations to elude and defend themselves. Pray can have adaptations such as horns, speed, muscle or coloration. Plants who are pray can develop spines, toxins or thorns.

There are many different types of defense mechanisms such as camouflage (cryptic coloration), Aposematic coloration, Batesian mimicry and Mullerian mimicry.

Cryptic coloration is when an organism's phenotype resembles or is even identical to its surroundings. This is used to make themselves harder to find by predators.

Aposematic coloration is another form of defense mechanisms. Aposematic means (in Ms.Foglia's terms) that an animal is saying " don't eat me , don't eat me." An organisms doesnt want to be eaten not only so they, obviously, survive and also because they are poisonus or just taste horrible. Most of the time animals have the colors black, red, orange and yellow to show predators that they shouldn't be eaten.

Batesian mimicry is when a creature is harmful and another animal that mimic's it is not harmful. The animal that is mimicing the harmful animal has an advantage because predators will stay away from it to not take a chance of getting sick or dying. An example is of the green parrot snake and the hawkmoth larvae. These two animals also have convergent evolution meaning they have the same solution to the same problem.

Mullerian mimicry is when all of the organisms that look the same are "nasty" ( meaning they're poisonus or taste bad). With this type of mimicry predators may evolve an innate avoidance of any animal or organism that looks like or is the harmful one.

Coevolution in Community:

there are three different types of coevolution in a community: Predator- prey relationships, Parasite-host relationships, and flower & pollinator relationship. This involves long term evolutionary adjustments between species.

characterizing a community:

every community has a structure made up of three diffferent parts: Species diversity ( how many different species are present, composition ( dominant or most abundant species, species with the largest biomass)( biomass is if you took an entire species and dried them out and weighed them), and a keystone species ( which plays a key role and has a strong effect on coposition of the community)

species diversity:

GREATER DIVERSITY = GREATER STABILITY

greater biodiverstiy offers more food resources, more habitat and more resilience in the face of enviornmental change.

keystone species:

they have an influential ecological role and can increase the diversity of a habitat.

keystone species can effect the community in two ways : they can increase nutrients from the bottom of the food chain up, or start at the top and can control herbavore devistation going down the food chain.

good night guys. hope this was helpfull!!!! oh and sherpa for tomorrow night is KIM!

Community Ecology

2007-10-22T17:11:00.000-07:00

Community Ecology

A community is all the organisms that live together in one place. Community Ecology is the study of interactions among all populations in a common enviornment.

Inside o community there are niches. A niche is the role a organism has in the community. Weather its a producer preditor or decomposer. There can't be more than one species in each niche. If there was both would out compete each other and the niche wouldnt work. In class today we saw the barnicles. The bigger ones pushed out the smaller ones. This is because there can't be more than one species in one niche at the same time. Basically one niche equals one species. AN example of this is Lions and Tigers.

Because there can't be members of the same species int he same niche some spiecies have devloped mmicrohabitats. This reduces competition between species. To do this the habititat is divied up into layers. In each layer a different member of the same species rains as king preditor.

Interspecific Interactions
Symbiotic interactions aren't always beneficial. Sometimes it may benefit you and sometimes you get owned. A few exapmles of symbiotic interaction are competition predation/parasitism, mutalism and commensalism. Competition doesn't benefit anyone (-/-). Eventually there is competitive exclusion, this is when one species takes over. Next theres predation/parasitism. THis benefits one animal (-/+). Someone gets food and someone gets eaten.

Next there is Mutualism. In mutalism both organisms recive benefits (+/+). An example of this are lichens, algaes and fungi.

Last there is commensalism. In commensalism one organism benefits and there is no effect on the other (+/0). AN exaple of this are barnacles on whales.
That's basically what we did in class today. Tomarows shurpa will be nicole. ^_^

Population Growth

2007-10-21T18:53:00.000-07:00

Hey Period 8+9, this is what Friday’s lesson was all about:

Basically what we were learning dealt with growth of populations on Earth and the effect population growths have on our planet. First, we dealt with what is called the Logistic rate of growth in which we learned that population, which can grow exponentially cannot always continue to grow because it is impossible. For example, if you refer back to the graph (which showed exponential growth) on the PowerPoint slide from Friday, (K) is the variable that stands for the Carrying Capacity of nature, while the other variable is (N), which stands for the number of individuals in a population. As one variable approaches the other, preferably (N) to (K) the effects of natural controls put its foot down and tries to alter this course. Without any natural control, the population would keep growing at an exponential rate and go over (K)’s limit. This would be an enormous problem in nature and on the ecosystem because the resources of that area are sure to run out do to its constant usage from the large population. Luckily nature always takes action in some way or form.

Now, going back to Carrying Capacity. (K) is the maximum size of a population that nature is able to support without reducing the quality or degrading the habitat. The Carrying Capacity can be altered with changes in resources of an environment. Again going back to the graph from PowerPoint, we see that the plankton population, after an exponential growth, decreases at a certain point because the organism overshot the Carrying Capacity. Now before, I said that changes in the resources in the environment varies the Carrying Capacity. One such example is the population cycles or Predator – Prey interactions. Referring back to the slide with the Snowshoe Hare and the Lynx, years that Hare populations are high (probably a warmer winter where grass is an available food source), the lynx population also high.

Next we learned about Human Population growth on Earth. For example the slide that dealt with the population growth of humans shows that advances of science, technology and industry are what led to an increase in the human population after the Bubonic Plague in the 1400’s. Also, in 2005, there are over 6 Billion people on Earth and that 82 Million people are being born each year. China and India having enormous populations, (1.3 Million People and 1.1 Million People). Could Humans be reaching Carrying Capacity? I truly believe so.

So what has been causing this sharp population increase? Well, countries that are still developing seem to have a higher fertility rate than that of developed countries (90% of births are in these developing countries). Also that the populations in these developing countries can either have a high, medium or low fertility rate in the future. Low fertility would be a better idea that having a medium or high fertility because we really don’t know what (K) is for the Human race, maybe 10 Million, maybe 15. A major factor that could aid in a better future for the world would be the education and income of people. If people were more educated and had more money problems like this wouldn’t happen. This could ultimately effect fertility rates and lead to a much lower population scenario in the years to come, benefiting Planet Earth.

Humans leave an ecological footprint. I feel that Humans are over-consuming resources on Earth and that we are destroying it as well. In the slide referring to Ecological footprints, the US uses so much land to support its population while India, whose population is much larger uses lesser land. The World is located on the deficit rather than the benefit side of its ecological footprint (which is a very bad thing people!), as well as our own nation because more wastes are being created from the consumption of resources such as land and water.

In the end, that’s pretty much all we learned on Friday. I think the Human race is heading onto a rough patch in the future. The Sherpa for Monday night will be Tom, (Your Welcome Tom). So that’s it, alright guys, Goodnight.
P.S, Sorry if its too Short or there arent enough pictures and such, I couldnt really find anything that could help illustrate the lesson. Sorry! :-)

More Ecology...

2007-10-18T17:08:00.000-07:00

Age Structure

Certain populations throughout the world have different growth rates within cohorts. In nations with a lack of medicine or education such as Kenya, there is too much reproduction occuring between 10-15 year old's. Because younger people are reproducing more than older people, the population size between 0-10 year old children is very large and steadily decreases as they age. In other nations such as Italy, there is a much lower population rate in younger peoples making their population size relatively steady throughout ages. Population sizes are a major effect on environments everywhere. In nations such as China overpopulation has had a negative effect on their nation and ability to survive.

Survivorship Curves

There are three types of strategies used by different species that help them survive. Type 1 includes humans and is when a species thrives in population size up and till the post-reproductive stage. Humans continue to live and reproduce successfully until they are past the age of reproduction then begin to die off. Type 2 includes Hydra's and is when there is a constant production and mortality rate throughtout the species. Year by year the population sizes remain the same and they continue to die off and reproduce consistently until death. Type 3 which includes Oysters has a very high mortality rate in the early stages of life. In Oysters, almost 99% of their population dies off before they can even reach a reproductive state. The survivors however, live a long life after their survival and must reproduce a lot. They cannot donate much energy or time to each individual offspring because 99% of them will die off so they will reproduce as much as possible then walk away. As an example, after the salmon are born they travel downstream to grow and develop. Once they become of age to reproduce they must swim all the way back upstream. This is of great cost to the parent salmon which is why once they arrive upstream, they reproduce as much as possible to get as much out of their journey as they can. This process not only affects animals but plants as well. The sunflower is an annual plant that only flowers one season. The flower cannot miss this season or else it could be fatal to the survival of it's next generation so they must strike while the iron is hot !

Reproductive Strategies

There are also reproductive strategies that can affect the population size in different species. If a species is K-selected, they have a late reproduction age and fewer offspring. They have less time in their lives to reproduce so they must take time to make sure the few offspring they create survive easily. Examples of this are primates and plants like coconuts.

Weedy plants such as dandelions produce many seeds and can grow very rapidly unlike the palms tree. In dandelions it is known that some out of it's many offspring will surivive and make more plants. With the palm tree, they produce a moderate number of very large seeds. Their large endosperm provides nutrients for the embryo. This process ensures that a larger portion of their small offspring with survive and succeed.

Population Growth

Change in population = Births - Deaths

dN/dt=riN

By using this formula, scientist's can presume the average number of offspring each couple had to of had in order for the population to grow from it's original size to it's present size. If every pair has two offspring, they are merely replacing themselves in the environment and not adding or taking away any numbers. But by only having less than two or more than two offspring you are changing the population and adding or taking away certain numbers from the species.

N= How many you start with. (specifically females being they are the ones that reproduce.)

r= The rate of growth, specifically how many offspring each couple had

ri= The intrinsic rate or how many offspring does your species generally make over time

t= Time

d = rate of change

Regulation of population size/ Introduced species

When certain species are endangered or introduced to a new environment, they can be protected and allow to reproduce exponentially. This is when there is no boundaries or limits set on the amount of offspring allowed to be produced. There are limiting factors that make population necessary to be regulated as well. Density dependant factors consist of competion for food and nesting sights and disease. Density independant factors consist of certain abiotic things like sunlight, rainfall and other sources of necessities. These are uncontrollable but still play a major role in the survival of a species in an environment.

When a species is introducted to a new environment it can greatly affect this new area. As an example, when European ships docked in North American shorelines, they brought along Zebra mussels. These mussels reproduce sporadically thus taking over entire shorelines. The fish who once used to lay their eggs on those shorelines are now in dire need to find a new ground to reproduce. Also, Purple Loosetrife which is a large flower that reproduces very rapidly and efficiently has taken over certain wetlands. These wetlands which were once home to all kinds of species is now infested with these purple loosestrife and these species which once lived there can no longer survive.

Some More on Ecology

2007-10-17T13:11:00.000-07:00

Hey guys, today we learned more about ecology. We learned that organisms interact with the enviornment, and face both biotic and abiotic factors. Biotic environment would be food, competitors and the predators.
Abiotic environment would include sunlight temperature water and soil. (Don't forget nutrients cycle while sunlight is always being input into the environment.) Populations are groups of individuals that are the same species at the same location.
Populations have all different ranges (how much area they live across), pattern spacing (how in the ecosystem the population is spread out), and sizes. When it come to the range they have geographical limitations.
Prey, predators, temperature, and water all act as boundaries for the range of populations. The boundaries sometimes allow for change, so the range can expand or contract. Endangered species are endangered due to limitations on range and their habitats.

There are three types of population spacing for populations. There's clumped ex: schools of fish or packs of wolves. Clumped spacing is the most commom and is an evolutionary advantage because it provides protection. There is uniform ex: birds. Uniform spacing can occur due to direct interaction with other individuals within a species, and it can involve an individual being territorial.
Also there is random spaccing ex: plants in a forest. For population size there are two factors that increase size and two that decrease the size. Birth and Immigration both increase population size, and to balance it out death and emigration decrease the size. Growth rate is looked at with three factors in mind. One is the ratio of male to female. The second is at what age females are able to reproduce. Also lastly, age structure. Factors that can control the growth and decline of populations are involved in demography. Scientists gather information on the populations and create statistics based upon their information. They can also use the information to create survivorship curves. Also scientists keep track of the number of individuals of each age group.

Tomorrow's sherpa will be Kelly S.

Ecosystems

2007-10-16T19:12:00.000-07:00

This was the Lesson for Monday and Tuesday!!!

So far we have talked about the three Domains and the different Kingdoms. These encompassed living organisms and their populations. Now we are jumping into the part of the world which includes both the biotic and abiotic factors. An Ecosystem is all the organisms in a community plus the abiotic factors. Ecosystems need three processes to occur in order to to be self-sustaining:

Capture of energy

Transfer of Energy

Cycle of Nutrients

There are Two Inputs in an ecosystem which are necessary. They are:

Energy
Nutrients

There is a constant source of energy that life of earth gets and that source is the sun. Sunlight is needed in order for there to be life. Energy flows through an ecosystem. Energy is lost through each trophic level. Producers have the greatest amount of energy and primary consumers receive less energy, then seconday consumers get a lesser amount and so on.

Nutrients on the other hand cycle through a system. There are a limited amount of nutrients on this earth and they are recycled because according to the first law of thermodynamics matter can neither be created nor destroyed. Both nutrients and energy go through a series of trophic levels. In general the nutrients are in an abiotic reservoir of some kind. They then are made available to producers, which then goes to consumers. Decomposers are the key to recycling most nutrients. They take the stored nutrients and put them back into the ecosystem to circulate the process. There are various elements that can be cycled. A couple important cycles are the carbon cycle, nitrogen cycle, phosphorus cycle, and the water cycle.

Carbon Cycle:

The Carbon cycle is the most known and famous cycle because of its importance. Organisms on earth are carbon based so carbon is essential for life. Carbon is found in the atmosphere and is made usable by the process of photosynthesis. Producers take carbon and in the process of photosynthesis make it usable to the rest of the biotic community. Carbon is returned back into the atmosphere with respiration as animals exhale it out as a byproduct of respiration. Carbon can also be returned into the atmosphere when humans burn fossil fuels which are the deposition of dead material.

Nitrogen Cycle:

The Nitrogen cycle is different in that nitrogen is mostly found in an unusable form. The triple bond of N2 prevents most processes from breaking down the compound. Bacteria are the only ones that can break down nitrogen into a usable form. Nitrogen-fixing bacteria make nitrogen available in the soil which consumers eat where nitrogen is then return to the soil with either decomposition or excretion. Denitrifying bacteria are the only ones that can return nitrogen back into the atmosphere. The nitrogen cycle is important because nitrogen is included in the base pairs of DNA as they are called nitrogen bases. Nitrogen also is important for the production of amino acids which code for proteins which enzymes are. Enzymes take part in many processes.

Phosphorus Cycle:

Phosphorus is found in rocks and minerals, usually igneous rock. Phosphates are leeched by water and are available in the water or soluble soil which are then absorbed by plants. Phosphorus cannot be returned to the abiotic reservoir but decomposers cycle the phosphorus. Sugar phosphates line DNA and phosphates are included in Adenosine Triphosphate.

Water Cycle:

The reservoir for water is usually the ocean, lakes, groundwater, or water vapor in the atmosphere. Precipitation transfers water from the atmosphere to the ground. Evaporation transfers some water from the ground to the atmosphere but transpiration does most of the job. Transpiration is the evaporation of water from plants as water escapes the stomates. The stickiness of water which causes one molecule of water to pull another molecule up a plant is called transpirational pull.

Deforestation has been breaking the water cycle. Groundwater is not transpired to the atmosphere, so precipitation is not created. This has led to desertification. Deforestation has caused nitrate levels in runoff to increase by 600% as shown by studies done in the Hubbard Brook forest region. There are people out there in the world trying to make a difference. The Greenbelt Movement in Kenya has been influenced by Wangari Maathai who has restored sustainable ecosystems and has won a Nobel Peace prize in 2004.

Deforestation in Eastern Angola

Deforestation in Middle Land, Pará Brazil

Wangari Maathai planting a tree at the Outspan Hotel, Nyeri, Kenya, to mark the launch of her autobiography, Unbowed

Deforestation Video:

Ecological Pyramid and Trophic Structure:

Food webs are linked into food webs because there is a complex connecting system of producers, preys, and predators. Depending on what a species eats or its niche, it can weave into the web at different levels. All levels are connected by decomposers who put the dead matter back into the cycle. The length of a food chain is limited by inefficiency of energy transfer. Energy is always lost at each level. in various processes. 50% of energy is passed the organism and is given off as waste. 33% of energy goes to cellular respiration and the rest of the 17% goes to growth. The loss of energy at each level creates an ecological pyramid in both energy amount and population size. The bottom of the pyramid has a lot of energy so it can hold a greater population while the top has very little energy so it can hold only a small population.

Review:

Energy flows through a system

Nutrients cycle through a system
Both energy and nutrients are needed to support an Ecosystem

More Information on Hubbard Brook Research go to: http://www.hubbardbrook.org/

More Info on the Grenbelt Movement go to: http://www.greenbeltmovement.org/

Tomorrow's Sherpa will be Kristen

Yep, Its the Animal Kingdom

2007-10-14T18:39:00.000-07:00

Hey Period 8 and 9! This was what Friday’s lesson was on:

The Animal Kingdom is the final kingdom of the Eukarya Domain along with the Protists, Plants and Fungi. What makes the Animals special from the other 3 Kingdom's you ask? Well first of Animals are Heterotrophs, in which the ingestion of other organisms is need in order for nutrients to be obtained. Secondly Animals have extreme complex bodies and their cells do not contain a cell wall, which allows for active movement to take place. Thirdly, Animals partake in Sexual Reproduction in which 2 organisms male and female mate with each other (Cool! just like these Turtles!). There is no alternation of generations nor are there Haploid Gametophytes. Animals stay Diploid for most of their life cycle with the exception of gamete production in which the Gametes, namely an Egg and Sperm are haploid.

Now, all animals came from one Ancestral Protist. From the Eukaryotes came the Animals and the first step of Animal Evolution wass Multicellularity. From there the Porifera group of more commonly known as sponges became apparent. Porifera's were primitive animals. They are invertebrate animals or have no back bone or spinal cord. Sponges were primitive because they lacked any distinct tissues organ but had specialized cells in them and were the only animals without organization. Porifera obtained its food by the process of Endocytosis or infolded its cell membranes like and Amoeba. Sponges have no symmetry what so ever.

Along with the appearance of Porifera's, step 2 came about in evolution by branching off of mulitcellularity and the introduction of tissues. Next came the Cnidarian’s or the Jellyfishes, Hydra, Sea Anemone and Corals. The Cnidarian group contained Tissues but no organs and had not one but two cell layers, outside and in, and Cnidaria's like the Porifera's are invertebrates in which they have no spinal cord. They are predators because the Hydra, Sea Anemone and Jellyfishes contain stinging cells on their tentacles surrounding their gut openings and had extracellular digestion in which enzymes are released into the gut cavity, break down the meal and spit the waste out the way it came in (Ew, that must smell horrific) . Cnidarian’s are radically symmetrical in which if the organism was cut in half in any direction the opposing half would be exactly the same. (I Do Not recommend being stung but one of these creatures apparently they are not a very good thing and happen to be extremely painful and annoying, thanks Tom)

Step 3 came about in Animal evolution with the branching off of Bilateral Symmetric organisms and the introduction of the Platyhelminthes otherwise known as the Flatworms! (Gross creatures). Once again these organisms are invertebrates. Tapeworms and Planaria are examples of Flatworms. Flatworms are mostly parasitic creatures and don’t need to digest food just absorb it. They are also bilaterally symmetrical meaning they have a mouth and an anus. To be bilaterally symmetrical allows for a high level of specialization within parts of the body of an organism, which is a MAJOR advantage. On the next step of Animal evolution was the branching off of organisms that contained body cavities in which the outside world was separated from the inside one. These newfound organisms are called the Nematoda group or the Roundworms (once again gross!). Like their flatworm cousin they are bilaterally symmetrical (have mouth and anus) and contain a complex and well-developed digestive system. Like their flatworm cousin they are also parasitic organisms for example the Hookworm or the Nematodes. (I hope to never experience these creatures, ever).
* This next stop is much more complicated! As there are 2 different branches created leading to different groups of different qualities.

The 1st branch is the Segmentation branch and the 2nd the Endoskeleton branch each branch having its own separate mini-branches. So lets talk about branch #1. Branch 1 which is Segmentation contains three mini-branches, Mini-Branch #1 being the Mollusca group (Mollusks). Clams, Snails and Squids are part of this group. Once again they are invertebrate animals and are bilaterally symmetrical (there are few exceptions of course). Most of these organisms have soft bodies being protected by hard shells. These organisms have a true Coelem or an internal digestive cavity separated from everything else. This is an advantage because when bilateral organisms eat they could be eating other harmful things and separating that from your body can help lots! Mini-Branch #2 is the Annelida group. These are the Segmented worms such as the earthworms, fan worms and the leeches. They are, like Mollusks, bilaterally symmetrical and contain a true coelem or internal digestive tract. However the segments on each organism are not specialized to serve a purpose. They are also invertebrates. The Final Min-Branch, #3, is the Arthropoda group. These are such organisms as the spiders (Yuck!), insects and crustaceans (lobsters and crabs).
Arthropods happen to be the most successful animal phylum because there are more of them than any other animal on Earth. Yes, they are bilaterally symmetrical and are invertebrates. Arthropods are segmented creatures therefore making jointed appendages possible. Also they have an exoskeleton made of Chitin + Proteins. That’s the hard shell you have to crack through when you’re at Red Lobster treating yourself to a nice expensive meal. (Unfortunately I’m too cheap to spend my money on dinner). In the Arthropod group there are the Arachnids, containing 8 legs and 2 body parts (Spiders, Ticks and Scorpions)
, the Crustaceans, containing Gills, and 2 pairs of antennae (Crabs, Lobsters, Barnacles and Shrimp),
and finally the Insects, containing 6 legs and 3 body parts (You should know what an insect is). Well that’s the Segmented Branch of phylum’s. On to Branch # 2! Yay! Branch #2 (Almost Done!) which is the Endoskeleton groups contains only 2 mini-branches. Mini-Branch # 1 are the Echinodermatas most commonly known as the Starfishes, Sea Urchins and Sea Cucumbers.

These creatures are different from others because they are no longer bilaterally symmetrical, they are radially symmetrically. Remember what that is? Well in other words if this organism was cut in half in any direction the opposing side would be exactly the same or symmetrical. Echinodermata's also have spiny exoskeletons. Finally! Here we are! The final min-branch, #2, are the Chordates otherwise known as the Vertebrates, in which each organism contains a spinal cord or back bone unlike invertebrates do. Vertebrates also contain and internal bony skeleton and have a skull that encases the brain and have a backbone encased in a spinal column. There are many different kinds of vertebrates for example fish, reptiles, amphibians, birds and mammals (<---- cool us!).
Our first examples of Vertebrates are Fish (Trout, Sharks and Salmon). Fish appeared over 450 MYA on Earth.

Fish happen to have a bony and cartilaginous skeleton, scales, fins and jaws equipped to their bodies. Fish have gills in order to perform gas exchange under the water. Fish are different from so vertebrates because they only have a two-chambered heart meaning a singled loop of blood being circulated throughout its body. This quality is given a name. It is called being Ectothermic in which the blood of the organism is the same as the outside of the organism (Temperature-wise). Fishes partake in external reproduction in which fertilization takes place outside of the body in the water (the embryo also develops in the water in a aquatic egg casing (Think Finding Nemo).

*Fishes evolved into land creatures called Tetrapods meaning four limbs. An example of this so-called transition organism is Tiktaalik roseae (Yes, we read about him a couple of weeks ago).

Our second examples of vertebrates are Amphibians (Frogs, Salamanders and Toads). Amphibians appeared over 350 MYA on Earth.

Amphibians, unlike fish have legs and are tetrapods. They also had moist skin meaning they needed to live near water in order for gas exchange to be possible by diffusion through the skin. This was because the lungs had positive pressures put on them and were inefficient. Amphibians were also different from fish because they contain a three-chambered heart in which the veins traveled from the lungs back to the organism’s heart. They are similar to fish because they are also ectothermic and partake in external reproduction (fertilization is outside of organism). But amphibians such as frogs have offspring that metamorphosize from tadpoles to adults.

The third examples of vertebrates are the Reptiles (Dinosaurs, Turtles, Lizards, Snakes, Alligators and Crocodiles). Reptiles appeared over 250 MYA on Earth.

They are very different from our first two vertebrates. For example reptiles have drier skin, scales and armor on their external body. They also have lungs for gas exchange and use thoracic breathing or negative pressure (unlike fish or amphibians). But Reptiles are similar because they are Ectothermic creatures and have a three-chambered heart. Reptiles partake in internal fertilization but have offspring that develop externally in an amniotic egg. In this egg there is a structure called a Allantois, which allows for the exchange of gas to occur.

The Fourth examples of Vertebrates are Birds (Finches, Hawks, Ostriches, Turkeys and Chickens). Birds appeared 150 MYA on Earth. Birds happen to be very different from the other three vertebrate groups. Birds have feathers and wings on their bodies and contain an endoskeleton of bones that are thin and hollow allowing to flight to be possible.

Birds are also different because they have extremely efficient lungs and air sacs. Birds are Endothermic creatures (the complete opposite of Exothermic creatures making birds very different) and have a four-chamber heart containing 2 ventricles and 2 atriums. Birds are similar to reptiles because they reproduce through internal fertilization and have offspring develop in an amniotic egg.

Our fifth and final vertebrate group appeared 65 MYA on Earth, with the extinction of the Dinosaurs, Mammals! (Finally, Humans,!) When the dinosaurs went extinct, many niches were needed to be filled giving mammals a great opportunity. Mammals have specialized teeth and have hair. Like birds, mammals are endothermic and have a four chambered heart, 2 atriums and 2 ventricles. Like birds and reptiles mammals contain lungs and have negative pressure (Mammals also possess a diaphragm). What makes Mammals special from the rest of the vertebrate groups is the fact that mammals not only reproduce by fertilizing internally our offspring develop internally as well in a uterus where nourishment occurs through a placenta making the offspring live young. Mammals also have mammary glands to feed their young after they have been born (Yes, Breastfeeding just like the woman on the subway lol).

* Vertebrates also have many subgroups. For example there are the Monotremes, which are egg-laying mammals. Only the Duckbilled Platypus and the Echidna and a minute number of mammals partake in this process. There are the Marupials, which are pouched mammals. The offspring have a short-lived placenta therefore the parent needs a pouch in order to care for its young by sheltering it. Kangaroos, Opossums and Koalas are known for this. The last examples of a mammalian sub-group are the Placental mammals. These mammals are the true placenta users for example the Shrew, Bat, Whale and Humans.

Well that’s it guys so thanks for reading, hope its helpful enough. The sherpa for Monday night will be Saad. Sorry Saad Man lol

Evolution of Plant Kingdom

2007-10-11T12:10:00.000-07:00

For 3 billion years the earth's terrestrial surface was lifeless. This means there was no plants or animals on the continents or the world. The 1st photosynthetic organinisms (orgainisms that use photosynthesis for food) were aquatic green algae.

Around 500 million years ago was when the first land plants evoloved. To survive on land these plants needed special adaptions. They needed these adaptations to protect them from drying out, to obtain and move water/nutrients, ways to exchange gasses and how to protect embryos. To protect themselfs from drying over time plants devloped a waxy cuticle. This would help them retain moisture better int he hot sunlight. Holes in a plant's leaves made gas exchange easy. Guard ceels would open and close the holes at approprate times to let gas eather in or out. To transport nutrients and water a series of pipes was devloped over times. These pipes are called xylem & phloem. For millions of years the embryos were unprotected. Over time the embryo was eventually protected in seeds.

Animals and plants have different life cylces. Animals spend most of their life as a diplod mutlicellular organisms. To reproduce animals as well as plants make gametes. This is where things start to differ between animal reproducion and plant reproduction. Through meiosis animals make haploid unicellular gametes. On the other hand plants use meiosis to make spores. From there they use mitosis to make a haploid multicellular gametophyte. A gametophyte is a plant that makes gametes through mitosis. Then fertilization occurs and the cycle starts over again. This is a disadvantage for plants because plants spend most of their life as a haploid. This means they only have one strand of DNA with no copy. If theres a mutation it could cause the plant to not function and die, where as diploids have two stands of DNA acting as an "insurance policy". If there is a mutation there is a good chance the other strand of DNA doesn't have it and the cell can still function proberly.

The first land plants were Bryophytes. More commenally known as mosses.

Mosses are non vascular; meaning they don't have pipes to transport water and nutrients. Because of this moss is usually small. Moss also have swimming sperm. To reproduce moss needs to be locaed near water so the sperm can fertilize an egg. The fuzzy moss you see is a haploid. The spores needed for reproduction sprout from haploids to for gametophytes. This is the onyl part of moss that is a diploid.

The first vasucalr plants were Pteridophytes, better known as ferns. The fern is a very leafy plant. It modled the first system of pipes. These are known as xylem and phloem. They also had as system of roots and leaves. Unfortunatly the fern still had swimming sperm so they still needed to live near water. Most of the ferns life is spent in the sporophyte stage. The leafy fern we are all familiar with is a diploid. The spores that are used for reproduction are located nder some of the leaves. To reproduce ferns alter their generations. The use differnt plants to make gametophytes. Their gametopytes are small haploid plants which produce gametes. These small plants are homospory. This means there is a male and female on the same plant. The fern is millions of years old. Forests of seedless plants decaded into seposites of fossil fules such as coal & oil.

The first seed plants were Gymnosperms, also known as conifers. THese new plants were vascular and heterospory. This means the have male and female gametophytes. The seeds they had were naked seeds. This means they arent protected by fruits. The seeds were spread by the wind. This meant that plants could finally reproduce away from water. The seeds were fertilized by pollen.Pollen eliminated the requirement for water fertilization. The pollen contained teh male gametophyte, while the seed had the female gametophyte. The seeds protected the embryo from drought and UV radiation.

The first flowering plants were called Angiosperm. They are diploids, vascular, were heterospory, they flowered of corse. The floweres enabled the plants to have seeds within fruit. This added protection as well as it made new modes of transportaion possible. An animal could coem along eat the fruit and the seeds would survive and pass out sometime later in a different place. Most flowering plants are trees and bushes. Examples of these are apples and strawberries. These plants also use pollen to fertilize seeds. The gametophytes (the haploid stage) are now microscopic.

The Flower came from modified leaves. The flower has a modified shoot with four rings of modified leavescalled petals. Under the leaves where the stem meets are the sepals. At the center of the petals are teh reproductive organs: the stamen- the male organ and the carpel- the female organ.
What are teh advantages of a seed? A seed offers protection for the embryo. It also has stored nutrients for the growth of the embryo.The first keaves of a new plant are in the seed. They are called cotyledons. A embryo could have be monocot (one leave) or dicot (two leaves). Most dicots are woody plants, trees, shrubs, or beans. Thel eaves hvae a network with veins. Most monocots are grasses palms and lilies. They contain leaves with parallel veins.

Well thats just about it. Tomarrows shurpa is going to be jesse.

Protists & plants!

2007-10-10T15:40:00.000-07:00

Protists are under the eukarya domain and is actually referred to as the "junk drawer" of kingdoms. Basically, if we dont know where an organism belongs, we place it in the Protist kingdom.Protists are classified as eukaryotes (meaning they have membrane bound organelles). Or using the metaphore that Ms. Foglia used, they're much like a multi-room house. There is great diversity within the protist kingdom, there are:

euglenoids

dinoflagellates and cilliates
brown algae and diatoms
red algae
green algae
and of course the MISCELLANEOUS group.

The problem with this diversity is that it is actually TOO diverse. Choanoflagellidia ( the miscellaneous group) is considered paraphyletic, meaning they actually aren't evolutionally related to, or have a common ancestor with protists.

The theory of Endosymbiosis is used to evaluate how organelles evolved. An ancestral eukaryotic cell will absorb an aerobic bacterium. The aerobic bacterium gives the cell energy while the cell protects the bacterium. These aerobic bacterium were not digested by the cell and soon became mitochondria. Then a eukaryotic cell with mitochondrion will absorb a photosymthetic bacterium which gives the cell enery and food and the cell gives the bacterium protection, so much like the mitochondria, this bacterium becomes the cholorplast. This gives you an idea of how organelles evolved in cells.

Protists, in their own microscopic world are actually predators. Protists are very diverse, and rage widely, from-

unicellular to multicellular
autotrophic to heterotrophic ( autotrophs make their own food through photosynthesis to gain energy, while heterotrophs eat other organisms to gain energy)
asexual to sexual reproduction
pathogenic to beneficial ( pathogens cause disease and can be fatal where others can be beneficial)
sessile to mobile ( stationary to able movement)

Protists move using flagellum [ whip-like tails], cilia [hair-like structures] or pseudopod [false feet].

Pathogenic protists can cause malaria, giardia and trypanosomes. The protists called plasmodium causes malaria , which lives in your liver and in your blood stream. They reproduce inside blood cells and ruptures when the paramecuim is grown, causing fever. Beneficial protists are phytoplankton and zooplanktom. Phytoplanktom does much of the worlds photosymthesis and produces 90% of atmospheric oxygen! THANKS PHYTOPLANKTON! & we can thank zooplankton for many marine animals because they are the bottom of the marine food web.

animal like protists (heterotrophs)

amoeba
paramecium
stentor

plant-like protists ( autotrophs)

euglena
algae
diatoms

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After the amazingly interesting lecture on protists we took a look at our bread mold and let me tell you, it was beautiful. haha- right. So, from this experiment we learned that moist and dry bread both develop fungus while dry bread kept in the freezer had not developed any fungus. SO KEEP YOUR BREAD IN THE FRIDGE. =] looking at the mold under the microscopes was, life changing to say the least. ew,ew, ew,ew,ew.

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Then we went over the kingdom of plants in the eukarya domain. We learned that protists were ancestors of plans and the first photosynthetic organisms were acquatic green algae. Plants evolved on land 500,000,000 ago. To protect them from dessication (drying out) they have a fat-based waxy cutical and they have stomates ( like spores) to keep gas exchange flowing. Xylem & phloem are used as water and nutrient conducting systems. Remember; Xy - High, Phlo-Low. Meaning xylem bring nutrients and water up to the leaves and flowers, while phloem takes water and nutrients down to the roots. The protection of the embryo comes from seeds.

^^xylem & phloem

Pland Diversity

Brophytes - non-vascular land plants (mosses)
Pteridophytes -seedless vascular plants (ferns)
Gymnosperm- pollen & "naked" seeds (conifers)
Anglosperm- flowers & fruit (flowering plants)

okay, i think thats just about everything. Have a good night! <3

oh - p.s. - tomorrow's sherpa will be tom. =]

Fungi, Fungus, Mushrooms, Decomposers uhmm.. yea

2007-10-09T12:05:00.000-07:00

Most people think ew! Freak! But what they should be saying is wow thats amazing thank you Fungi! These little creatures are decomposers that break down materials for us because... what we have is all we got! Also they are not closer to plants but animals!!

General Characteristics of a Fungus are...

They are Eukaryotes meaning they a single or multicellular organism with distinct membranebound nucleus. Unlike the cell wall of a plant cell which contains cellulose the fungus has a wall made of chitin and no it isn't pronounced chi-tin but kahy-tin... get it right!! This sort of membrane makes a cracking noise like a crab shell when broken. amazing isn't it? The Fungal body contains mycelium made up from hyphae.Hyphae develop reproductive structures that branch to holes for spores. mycelium have filamentous, a threadlike substance for greater surface area to absorb food.

Ecological Roles

As decomposers Fungis do just what there name means... they decompose and recycle nutrients into the awesome earth cycle. Other than making things rot and smell bad; the fungi are our greatest recycling team more so than all the recycle bins put together in the world!!
Some decomposers are actually symbiotic with organisms such as plants. Mycorrihizae is a fungi which stem into the plant's root extending its water absorbing surface area!! oh and symbiotic means absolutely necessary relationship. There are endomycorrhiza which are in the cells of plants that really don't help too much but this amazing ectomycorrihiza rooted cell which have roots in between cells create that special bond and help these poor things get some water... well alot of water.

Nutrition Facts
Well how the fungus do the fungi obtain nutrients such as nitrogen. We all know how amazing nitrogen is and well so do the fungi which trap nematodes these disgusting little worms who feed on fungi and paralyze them with special juices and ultimately absorbs and digests the nitrogen out of them. Gross... But cool that these fungi can digest without the hassle of chewing but rather absorbing like in the video above! Aside from nematodes. Fungi feast on all different types of organisms through absorbtion escpecially in plant cells. By absorbing the plant cell the fungi become one with the plant and live symbiotically.

Fungi have 4 major branches

the chytriduimycota, the Zygomycota, Basidiomycota, and Ascomcota

Sex or Reproduction but Sex sounds better
Unlike humans or any othe animal which have intercourse enojoyably and with a partner the fungi don't do sexual reproduction but rather asexual. Girls are haploids which is expressed as 2n where the male is haploid as n the female has 2 chromosomes x and y to give where as the male has only 1. Fungus such as yeast just asexual reproduce... boring.. but for mushrooms this is the most intresting nature sex where the fungi let out spores and is carried by the wind to meet other spores and become a new fungi... wow confoosed??

Fungi Cycle

Bread molds are haploids having only themselves to reproduce with so they send spores and meet other haploids and only through meeting another haploid can they become a haploid for a short period to make more spores. kind of a homosexual one night stand except they can't reproduce...

Mushrooms are kind of cool kinda... well they have gills lined with basida which have zygotes attached to the bottom which shoots spores to meet other spores to make another fungi! basically well a mushroom gill sends out spores it must meet a different spore we label the spores as + and - so a + needs a - and a + needs a - to make a new fungus.

The thing below is called a fairy ring people wonder why this formation of mushroom and myths arose such as fairies have danced here but to science it is laudable hahaha....(not funny) anyway the fact is underneath the ground there is a huge fungi down there all rooted down and the mushrooms around it are the border line to where the fungi is... wow huge

i'm not sure what much more I can write except if I did something wrong criticize and if I did something right then :p haha

Oh and for those of you who missed it here's Ms.Foglia's clever joke
A Mushroom walks into a bar and the bartender says we don't serve your kind here and the mushroom says why i'm a Fungi!

The lucky sherpa for tonitee is Nicole...

have funn...-_-

Classification

2007-10-01T14:47:00.000-07:00

Scientist classify all organisms into different groups. Originally the Five Kingdom System was used. This system was divided into Monera, Protists, Plants, Fungi, and Animals. After genetic comparisons and study, a new system was created, known as the Domain System. Monera, from the kingdom system, was separated into bacteria and archaebacteria. Then, the other domain is Eukaryotes, which contains protists, plants, fungi, and animals. The protist group is very diverse and therefore this classification system may soon be changed again as more information is found on protists.

Old 5 Kingdom System

New 3 Domain System

Prokaryotes:

Bacteria live everywhere, on and in plants and animals, in soil, oceans, extreme temperatures, on living and on the dead. There are also several different kinds of bacteria, including bacillus, bordetella, clostridium, escheichia ( also known as E. coli), spirulina, staphylococus, streptococus, and salmonella.

The structure of a prokaryotic cell can be bacillus ( straight and rod-shaped), coccus( spherical shaped), and spirillium ( long and helical shaped). Prokaryotes are unicellular, but sometimes individual cells will adhere to eachother forming a matrix. Even though they are attached, each cell still retains its individuality. The cell size of prokaryotes is 1/10 that of eukaryotes, and the internal structure contains no internal compartments and no membrane bound organelles. Variations can be seen within cell interiors of different prokaryotes. Cyanobacterium contains internal membranes so that it can go throught the process of photosynthesis, wheras aerobic bacterium's internal structure allows it to respirate.

Prokaryotes can either be Gram-positive bacteria or Gram-negative bacteria. The Gram positive bacteria have a thicker peptidoglycan wall and stain a purple color while the Gram-negative bacteria contain less peptidoglycan and do not retain the purple colored dye. Gram-negative bacteria are more harmful than Gram-positive bacteria because they are more resistant to antibiotics.

Prokaryotic Metabolism:

Bacteria get their energy and nutrients one of two ways. Either they are autotrophs or heterotrophs. Photoautotrophs are photosynthetic bacteria such as cyannobacteria, and they produce their own energy throught the process of photosynthesis. Chemoautotrphs also make their own energy and nutrients through the process of oxidation of inorganic compunds such as nitrogen, sulfur, hydrogen, and others. Heterotrophs live on plant and animal matter. They are known as decomposers or pathogens. Pathogens are disease causing organisms. Decomposers are very helpful to our environment because they feed off of dead organisms and then put the energy from them back into the environment.

Bacteria reproduce asexually every twenty minutes. Mutations can occur very quickly in bacteria because of their ability to rapidly reproduce. Genetic Recombination is when bacteria swap genes.

Good Bacteria vs. Bad Bacteria

There are both good and bad bacterias. There are disease causing microbes which cause plant and animal diseases such as fruit rotting, blights and wilts. Animal diseases include tooth decay, ulcers, anthrax, botulism, plague, leprosy, STDs, typhoid, pneumonia and lyme disease. Leprocy is one of the scariest diseases to observe. Good bacterias are decomposers ( if there were no decomposers, life one arth would cease). Good bacteria also aid digestion (E.coli) because they have a cellulase enzyme and digest cellulose in herbivores and also produce Vitamins K and B12 for humans, which is crucial to live. Also, good bacterias produce foods and medicines, such as yogurt and insulin.

This is a video I found on bacteria...

Tomorrow's Sherpa is Seung

2007-09-27T14:22:00.000-07:00

Origin of Life on Earth.... as we know it

Today's lesson focused on the origin of life. To understand the origin of life we must first understand what life is defined as.

Life -- The property or quality that distinguishes living organisms from dead organisms and inanimate matter, manifested in functions such as metabolism, growth, reproduction, response to stimuli, development (change over a lifetime), reproduction, and regulation (homeostasis).

Now that we have the definition of life down, we may proceed to The Origin of Life, or at least the three main hypotheses:

1. Creationism -- Was life created by a supernatural or divine force (i.e.: God). This hypothesis is untestable. (extra information: In 1925, the Scopes Trial ("Monkey Trial") was publicized due to the teaching of Darwin's theory of Evolution in a Tennessee high school by John Scopes. This broke the doctrine which stated that no information which denied the validity of creationism could be taught in public schools. Scopes was found guilty and paid a $100 fine. This law as repealed in 1967.)

2. Extraterrestrial Origin -- The idea that extraterrestrial objects such as meteorites and comets that struck the earth were the original source of organic materials such as carbon. This hypothesis is testable.

3. Spontaneous Abiotic Origin -- Abiotic: meaning non-living. The idea that life spontaneously arose from non-living materials such as inorganic molecules. This hypothesis is testable.

---- Abiotic Synthesis: In 1920 Oparin and Haldane proposed the reducing atmosphere hypothesis in which life originated in an environment that contained less than 1% oxygen and the majority of the atmosphere contained Carbon dioxide. In 1953, Miller and Urey found a way to test this hypothesis: an apparatus. This apparatus simulated early earth environments of which it was believed life formed from. The experiment resulted in that organic compounds such as amino acids, simple sugars, and nucleotides such as adenine (the building blocks of life) were formed. A diagram of this could be seen below:

Origin of Cells:

One theory suggests that the membrane of the cells were developed from lipid-membrane bubbles in that they were easily split into more bubbles, thus creating more cells. These proto-cells separated the inside from the outside (non-polar membrane). These cells preformed metabolism and reproduced.

3.5-2.0 billion years ago Prokaryotes (comprising the bacteria and cyanobacteria, characterized by the absence of a distinct, membrane-bound nucleus or membrane-bound organelles, and by DNA that is not organized into chromosomes) dominated the majority of life on earth. See diagram of ancient fossilized prokaryotes

Stromatolites: fossilized mats of prokaryotes resemble modern microbial colonies see photo below:

Photosyntheic Bacteria: Cyanobacteria, blue-green algae:
-Oxidized the atmosphere. They made aerobic respiration possible.

Eukaryotes: A single-celled or multi cellular organism whose cells contain a distinct membrane-bound nucleus. Developed by enfolding plasma membranes into and around the center going form an oval to a spherical circular. Provided internal micro-environments. The DNA was protected now in the nucleus.

Endosymbiosis: A mutually beneficial relationship in which one organism lives inside the other. This theory, developed by Lynn Margulis, is supported by structures found in modern cells such as mitochondria and chloroplasts that resemble bacterial structure, have their own DNA as does bacteria, move freely within the cell, and reproduce independently from the cell thus giving the illusion that they are separate organisms.

Evolution of Eukaryotes: Mitochondria and Chloroplasts

Mitochondria - cell engulfed aerobic bacteria but did not digest them. Provided a mutual-beneficial relationship.
Chloroplasts - Cell engulfed photosynthetic bacteria but does not digest them. Provided a mutual-beneficial relationship.

Which came first the RNA or the DNA?
RNA is most likely the first genetic material produced in that it has more functions in a cell. It codes information: self replicating, makes inheritance possible, allows for natural selection and evolution. Enzyme functions: robozymes and replication.

Classifying Life

Five Kindoms:
Monera
Protista
Plantae
Fungi
Animalia

Three Domains ("Super Kingdoms"):
Bacteria
Archaea - (extremophiles-live in extreme enviornments)
Eukarya - Protists, fungi, plants, animals

And heres a few videos for your entertainment:

1942 Fantasia: The Rite of Spring - Part 2: Evolution

This is just a few cartoons put together with evolution parodys. Dilbert, Family Guy, and Simpsons are on it (its the same Simpsons on Kim's post, but the others are pretty good).

-- Shannah

oh and the next sherpa is ............. Maria

Were it all started: The origin of species!!!

2007-09-25T19:14:00.000-07:00

Hello everyone. Well the point of todays class and the main point that Ms.Foglia was tying to make was how and why species diverged from each other. There are two ways: Pre-Reproduction and Post-Reproduction.

First and foremost, What is meant by the word species??? that is the question...
Species is a population where the organisms are able to interbreed and produce offspring that will be able to survive and reproduce. The organisms must be reproductively compatible which means they are able to mate with each other.

OK well thats said huh? So whats next... PRE-Reproduction and how it causes species to diverse. WooHoo

There are 6 different barriers that may be obstacles and may prevent mating or inability to fertilize if mating occurs. Here they are:

Geographic Isolation: There is a physical barrier that does not allow the species to inter mate. The species will occur in different areas.

Ecological Isolation: Species occur in the same area but occupy different habitats. This means that the seldom if never meet.

Temporal(Time) Isolation: Species breed during either different times of the day, different seasons, or different years. This means that the species cannot mate.

Behavioral Isolation: Unique behavior patterns isolate species. If an organism doesn't recognize the calls, dances, songs, etc. then they do not mate.

Mechanical Isolation: Morphological differences can prevent successful mating.

Gametic Isolation: The sperm of one species may not be able to fertilize the egg of another species.

POST-Reproduction

The three post-reproduction barriers, which prevent hybrid offspring from developing into survivable fertile adult, are a)reduced hybrid viability b)reduced hybrid fertility c)hybrid breakdown.

Reduced Hybrid Viability- The hybrid would be very fragile. The genes of the different parents will interact and impair the hybrids development.

Reduced Hybrid Fertility- The hybrids will survive and live a full life but they are unable to produce offspring. Probably because the number in chromosomes may differ in the parents and cause the hybrid to have abnormal gametes.

Hybrid Breakdown- hybrids could be fertile and viable in the first generation but when they mate offspring are feeble and sterile.

Well folks thats all there is. See you all in class tomorrow or i should say today cause its already 12:12am.

OH WAIT ONE MORE THING...

HAHAHA Just searching for a cool cartoon and look what i can across. I think you'll all enjoy it.

Hey guys just check out this link i think the banana thing is cute. You'll get it once you see it.
http://evolution.berkeley.edu/evosite/evo101/VC1gReproIsolation.shtml

Evidence of Evolution by Natural Selection

2007-09-24T18:41:00.001-07:00

Dear Mrs. Foglia's Favorite Class Ever,

Today we reviewed many parts of evolution! One thing we talked about was the anatomical record which is made of homologous structures. These are when organisms have the same structure that performs different functions. For example we saw the same structure in a human, cat, whale, and bat. Another example we saw was emryological development. We saw how cells for a fish made gills. No humans do not have gills, but we have the same cells that serve for a different purpose in our body.

The opposite of homologous structures are analogous structures. These structures have similar external form, and functions. These structures also have different origin, and internal structure. The best way to explain this would be don't judge a book by it cover. The organisms may look similar on the outside but inside are very different.

Another topic discussed in class to help us understand natural selection was peppered moths. We saw percents of dark vs. light moths. This was an example of industrial melanism. Industrial because it was caused by huge industries. Melanism because the brown color in all animals is called melanin. When pollution was low, and lichen existed on trees light colored moths made up 95% of the population. Instead when factories created soot covered trees, and killed lichen dark moths blended better with their surroundings. Then in the mid 1900s clean air laws went into affect, and as a result light moths made up most of the population. This is an example of natural selection, because depending on successful traits such as color helped moths to have a high survival rate and reproduce. The moths who fit their surroundings best could escape predators.

I found this youtube video on evolution and it is weird to say the least!

The sherpa for tom. will be Kim

2007-09-23T15:53:00.000-07:00

Hello period 8 and 9 bio class, its Jaclyn.On Friday September 21st the class reviewed the requirements for what was needed on the Population Genetics Lab. This Lab was suppose to represent populations under different conditions of evolutionary change. The first being in Hardy Weinberg equilibrium, the second being in a selection against homozygous recessive, the third being where the homozygous had an advantage and the fourth was the case with genetic drift. Through case four we see how Genetic Drift proves that Hardy Weinberg Equilibrium is a synthetic theory because we see how genetic drift occurs and causes evolutionary change. For case numbers 1, 2, and 3 we had an original population of 17 individuals with 34 alleles(2 per each individual). For Case number 4 we had 6 individuals and 12 alleles. After each person in the class collected their own information for the lab the class combined information together, and calculated the frequencies of the genotype by using the Hardy Weinberg equation which would be.
p² + 2pq + q² = 1
The data is as follows:

Case #1:Hardy Weinberg Equilibrium
Generation# :p2 (AA)- parental=.25 F5=.18
2pq(Aa)- parental=.5 F5=.70
q2(aa)- parental=.25 F5=.12
Frequency of alleles:p(A)-.5 q(a)-.5
p(A)-.53 q(a)-.47

Case #2:Generation# :Homozygous recessive
p2 (AA)- parental=.25 F5=.592pq(Aa)- parental=.5 F5=.41q2(aa)- parental=.25 F5=.0
Frequency of alleles:p(A)-.5 q(a)-.5p(A)-..79 q(a)-.21
Case #3:Generation# :Heterozygous advantagep2 (AA)- parental=.25 F5=.18 F10=.352pq(Aa)- parental=.5 F5=.82 F10=.65q2(aa)- parental=.25 F5=.0 F10=.0
Frequency of alleles:p(A)-parental=.5 q(a)-parental= .5p(A)-F5= .59 q(a)-F5= .41
p(A)-F10=.68 q(a)-F10-.65

Case #3:Generation# :Heterozygous advantagep2
(AA)- parental=.25 F5=.18 F10=.352pq
(Aa)- parental=.5 F5=.82 F10=.65q2(aa)- parental=.25 F5=.0 F10=.0
Frequency of alleles:p(A)-parental=.5 q(a)-parental= .5p(A)-F5= .59 q(a)-F5= .41
p(A)-F10=.68 q(a)-F10-.65

Case #4:Genetic Drift.
Each group had different data.

This lab demonstrated that the Hardy Weinberg theory does not work out, because of five agents that affect evolutionary changes. In Hardy Weinberg equilibrium allele frequencies do not change. Hardy Weinberg populations are non-evolving populations that are not affected by the five agents of evolution including, genetic drift, gene flow, mutation, random mating, and natural selection. We know that this can not occur and that these five agents cause evolutionary changes in nature.

The following is a link to better understand the Hardy Weinberg equilibrium and the five agents of evolution.
http://http://zoology.okstate.edu/zoo_lrc/biol1114/tutorials/Flash/life4e_15-6-OSU.swf

http://http://www.phschool.com/science/biology_place/labbench/lab8/intro.html

Later class!
Tommrows sherpa will be Kerrie Sheldrick.

Measuring Evolution of Populations

2007-09-20T18:02:00.000-07:00

Today, in period 8 and 9, we discussed Measuring Evolution of Populations. We discussed that evolution is the change in allele frequencies in a population. Also something we discussed in this lesson was what would cause allele frequencies not to change. Which include, very large population, no migration, no mutation, random mating, and no natural selection. This is only hypothetically speaking, this would be very hard to accomplish in a realistic population.
Hardy-Weinberg equilibrium was a major part of the lesson today. G.H. Hardy was a mathematician and W. Weinberg was a physician.

G.H. Hardy

W. Weinberg

This does not really exist anywhere, it serves as a model. It is a null hypothesis. This is used to measure if forces are acting on a population; measuring evolutionary change. When counting alleles, the frequency of the dominant allele is represented by p. The frequency of the recessive allele is represented by q. The frequencies of the two alleles must add up to 1 (100%). The equation used to represent this is p + q=1. When you are counting individuals, using the Hardy-Weinberg theorem, the frequency of the:
homozygous dominant: p x q = q²
homozygous recessive: q x q = q²
heterozygotes: (p x q) + (p x q) = 2pq
Like the frequencies of the alleles, all individuals add to 1 (100%). The equation used to represent this is p² + 2pq + q² = 1. These equations can only work, hypothetically, if the population is in Hardy-Weinberg equilibrium.

We also discussed sickle celled anemia.

Sickle cell anemia affects 1 out of 400 African Americans. It is an inheritance of a mutation in gene coding for hemoglobin. Low oxygen levels causes red blood cells to sickle, which then can lead to the clogging of blood vessels;capillaries, if two sickle cells stick together. This can be lethal to younger children, but have a less, but serious effect on older generations. The heterozygotes have an advantage in this case, they are free of both malaria and sickle cell anemia.

The sherpa for tomorrow will be Jackie K.

evolution of populations

2007-09-19T19:22:00.000-07:00

Hey everyone in period 8&9 AP Biology. Todays lesson was on the Evolution of populations which is covered throughout chapter 21. Today we Learned that natural selection affects populations and changes them over time, and we went into detail on how researchers know populations are changing and what causing the change. A main point of this lesson was that Individuals are selected, populations evolve Natural selection acts on individuals. Individual organisms can not evolve they are selected or not selected to survive and reproduce. Many species have adaptations to specific enviorments to prevent predation, such as pocket mice in desert lava flows, their color helps them blend in with the land to prevent themselves from being easily spotted by a predator.
There must be differences and Variation within a population for evolution to occur. Variation is the raw material for natural selection. Variation can be seen from the size of horses to the color of shells and in many other ways. The organisms with the best survival and reproductive success also know as fitness are those that pass on their traits to future generations. Sexual reproduction is successful because it makes the offspring different from the parents and hopefully passes on the traits of good fitness.
A common question would be What is a selecting force? or even, What force is acting on populations to cause a change? Well the answer can be found as one of the 5 agents of evolutionary change. These agents are Mutation, Gene flow, Non-random mating, Genetic drift, and selection. Mutations create variation. They are a change in DNA which in turn changes traits, which can be phenotypes, which is a form of variation natural selection can act upon. Gene flow is the movement of individual and alleles in and out of a population, basically through migration. Populations intermix rahter then staying isolated which affects their variation, and reduces differences between populations. This is seen in the world today with many new faces in America from countries all over the world and they are reproducing with people of other cultures to create a blending of traits. Non-random mating is mainly sexual selection which in many organisms is females choice, and not everyone has an equal chance to have offspring. Genetic drift is based on chance events. This includes the founder effect in which a small group of a population is seperated, like the finches and evolve form the genetic variation they have, making a rare allele become common. Genetic drift also includes the bottleneck which is a random event usually a disaster, that constricts a populations kills off a large percent of a population leaving a small percentage left to expand. There are many conservation issues today trying to increase variation among populations as much as possible.

and tomorrows sherpa is Mia.

Evidence of Evolution by Natural Selection

2007-09-18T12:38:00.000-07:00

Hi everyone. Today we started off by talking about fossil records and made way into the links between species. One of Mrs. Foglia's key points was that changes in the climate and environment can lead to extinction. Some creatures have adaptations acquired through many generations that allow them to survive, others that are not suited for the change would start to die off. We also talked about an interesting piece of information, knowing that all life started in the ocean, some creatures had to be links from sea to land animals.

The tetrapod is a missing link, and it was only discovered last year! But also, if mammals evolved on land, some had to return to the ocean for animals such as whales and dolphins to be sea mammals. Also, Mrs. Foglia showed us homologous structures and analogous structures, and we talked about convergent evolution and parallel evolution. Homologous structures are structured and developed similarly, but serve different functions and look differently externally. They have a common ancestor. Analogous structures are just the reverse, they have similar functions and external form, but the internal structure and development is not the same. There is no common ancestor in this evolutionary relationship. Analogous structures are part of convergent evolution. The idea of convergent evolution is that different creatures evolved in a similar way externally, though internally they are very different. Parallel evolution is when creatures, though separated and not closely related, served same job in their environment. Then, we finished off by talking about vestigial organs. These are structures that basically have no function, such as the appendix in humans, and a pelvis in a whale.

The sherpa for tomorrow will be KellyP.

Sexual Selection

2007-09-17T12:45:00.000-07:00

Hey 8th period AP biology class members. Today we discussed many things in continuation on the topic of evolution and natural selection. We started off going over the lion mane slide. The key point Mrs. Foglia was showing with that slide was that animals do not choose a mate because they know that they have better genes, but because they are just attracted to that member of the opposite sex. If it happens to be that the member of the opposite sex has good genes, then it's great, but that is not what animals are actually looking for.

Also during class today we discussed phenotypes and genotypes. Phenotype is the physical appearance, anatomy, while genotype is the genetic make-up of an organism. The genotype controls the phenotype of an organism.

We also discussed how alleles (genotype) determine the color or physical appearance (phenotype) in the power point on straw fish. In the example, two blue alleles means the fish would be blue, two yellow alleles means the fish would be yellow, and one blue allele and one yellow allele means the fish would be green. The powerpoint on the straw fish shows how natural selection is based on the phenotype which changes the frequency of alleles. With the example given during class, the predator ate most of the yellow fish because they did not blend in easily, natural selection, which affected the allele frequency because with the yellow fish gone there are less yellow alleles. Remember, even though the frequency may change, in this case yellow decreased and blue increased, the total remains the same.

Tomorrow's sherpa will be Shana Lunney.

Natural Selection

2007-09-12T07:01:00.000-07:00

Hey period 8 AP Biology, today in class we went over many forms of selection and their effects on an environment. Certain species need to develop adaptations in order to survive in their surroundings. As seen in the "Effects of Selection" slide on our powerpoint, there are three main types of driving changes in a population. Directional Selection basically means that there are two extremes within the species. As an example, larger horses and smaller horses. If the larger horses are the only variation of the species that will survive then this will be the dominant gene passed on throughout generations. In Stabilizing Selection, the two extremes cannot survive and that variation which is in the middle will carry on. When field mice of dark color, light color and medium tan all live in a field, when the field turns to a tanner color the middle variation will be the only one to survive. In Stabilizing Selection it is favorable to obtain the middle gene. Disruptive Selection has two extremes which both benefit from their environment. Birds with smaller beaks can fit into tiny holes in trees and gets smaller insect. Although, birds with larger beaks can break open larger seeds. If you are anywhere in the middle, you lose both of these abilities and cannot survive.
In Sexual Selection, there are certain aspects of an organism's civilization that are plainly luck of the draw. If you are a male, by obtaining these desired characteristics such as blue feet, large maines or size you are able to survive and hopefully reproduce more efficiently while passing on these traits to your offspring. There is no point to survival for these organisms if they do not sucessfully reproduce and pass on the trait to as many offspring as possible.

Evolution is "So overwhelmingly established that is has become irrational to call it a theory."
-Ernst Mayr

I found this pictures on google describing the change in whales which I thought was pretty crazy.

Also this link has a lot of terms and concepts concerning adaption, genes and selection.

http://www.wsu.edu/~rquinlan/basics.htm

I'm not really sure how to finish this off but if anyone needs help uploading pictures or videos email me and you can ask me for help there.

Darwin & Evolution

2007-09-11T10:34:00.000-07:00

Today we learned about natural and artificial selection. For hundreds of thousands of years the theory of the gods creating all life on earth had been accepted and people were not as bold as to question this belief until circa 1800's. Contrary to this belief we have fossil records showing creatures that are very similar to present creatures. Also existing are archeopterix which show the link between reptiles and birds.
Here is a link that i found of a recent journal further explaining this subject: Transitional Forms

Charles Darwin came across fossils of extinct armadillos however he found that the living armadillos on the same continent (South America) were very similar and this helped prove his theory of natural selection and that creatures cannot adapt over a lifetime but through reproduction (however he did not come up with the theory of DNA and genes). He concluded that those armadillos who were not born with the favorable trait did not survive and eventually this favorable trait became normal and only this type of armadillo would survive. He found the same situation with the Mylodon (giant ground sloth) and the Modern sloth.

Another scientist who had ideas about evolution was LaMarck. LaMarck understood that adaptations took place, but was a little off in his theory. LaMarck believed that organisms adapted over their lifetime, like in this cartoon that I found.

Evolution by Natural Selection

2007-09-10T08:30:00.000-07:00

The lesson for Monday September 10th covered chapter 22 "The Evidence for Evolution". Today's lesson went over the concept of evolution by natural selection. People often believed and were lead to believe that all life was made by the creator in perfection and was unchanging. There is evidence all around the earth such as the fossil record which gives evidence that the world is always changing. Charles Darwin was a naturalist in the 1800s who traveled on the Beagle to observe the world around him. He did not come up with the idea of evolution. Evolution had been understood by people before him like the Egyptians since evolution means change over time. Darwin came up with evolution by natural selection.

A portrait of Charles Darwin:

Natural selection by definition is the differential reproduction of genotypes; caused by factors in the environment which leads to evolutionary change. This means that certain traits are selected in a species that are advantageous and help them to survive, depending on their environment, and are passed on to future offspring. Darwin's most famous supporting evidence is the finches in the Galapagos Islands. There he observed that there were different types of endemic birds with similar phenotypes. Later he found out that all the birds were finches. All the finches came from a common ancestor but they had adaptations which helped them to survive in the environment. All had different shaped beaks which were best for their survival. The variation in beaks within the same species enabled some to obtain food successfully in the different environments.

Adaptive radiation is where different species originate from a similar ancestor and they inherit different successful adaptations to fulfill their niches. A niche is the position of a species or population in the ecosystem. Organisms cannot choose the traits they want, they cannot adapt but have adaptations.

Lamarck was a naturalist who believed that organisms could adapt and change during their lifetime and pass those useful traits onto future offspring. Darwin and Lamarck were both observers of the world who had great ideas about how the world worked but evidence now shows that natural selection is more accurate and that organisms cannot choose their own genes and that genes are picked at random when an organism is created.

In conclusion, Darwin did not propose evolution but evolution by natural selection. He supported his idea with experiments like that with the finches from the Galapagos Islands. Natural Selection would fall under Evolution in the eight themes of biology.

I found these cartoons online. These show that organisms cannot adapt and choose traits they desire but it is a long process where organisms have adaptations.

This diagram shows the difference between LaMarck's theory and Darwin's using giraffes (click to see larger version):

To read more about Charles Darwin's Origin of Species or his journal and diary while on the Beagle go to this site: http://darwin-online.org.uk/

How to Blog Safely

2007-09-09T17:34:00.000-07:00

Blogging is a very public activity. Anything that is posted on the Internet stays there. FOREVER! Deleting a post simply removes it from the blog it was posted to. Copies of the post may exist scattered all over the Internet. That is why we need to be careful and follow some simple, clear, safety rules.

FIRST RULE:
To protect your privacy, you need to set up your account using ONLY your first name. This means that many of you need to go in and change your profile. If you have the same first name as another classmate, then let's add only your last initial to your first name, like KimF.

SECOND RULE:
We do not use pictures of ourselves in our profiles. If you really want a graphic image associated with your posting use an avatar -- a picture of something that represents you but IS NOT of you.

Other teachers who have blogged with their classes have come up with a list of guidelines for student bloggers.

One of them, Bud Hunt, has these suggestions, among others:

Students using blogs are expected to treat blogspaces as classroom spaces. Speech that is inappropriate for class is not appropriate for our blog. While we encourage you to engage in debate and conversation with other bloggers, we also expect that you will conduct yourself in a manner reflective of a representative of this school.

Never EVER EVER give out or record personal information on our blog. Our blog exists as a public space on the Internet. Don’t share anything that you don’t want the world to know. For your safety, be careful what you say, too. Don’t give out your phone number or home address. This is particularly important to remember if you have a personal online journal or blog elsewhere.

Again, your blog is a public space. And if you put it on the Internet, odds are really good that it will stay on the Internet. Always. That means ten years from now when you are looking for a job, it might be possible for an employer to discover some really hateful and immature things you said when you were younger and more prone to foolish things. Be sure that anything you write you are proud of. It can come back to haunt you if you don’t.

Never link to something you haven’t read. While it isn’t your job to police the Internet, when you link to something, you should make sure it is something that you really want to be associated with. If a link contains material that might be creepy or make some people uncomfortable, you should probably try a different source.

Look over the guidelines and add any ones you'd like to suggest in the comments section below this post. I think Bud's suggestions are excellent -- clear and easy to follow. We'll be using these from now on as the basis for how we will create our blogs.

You've got to pay attention to the list of "What Not To Do"!

Regards,

KBF

Cycle 2 Sherpa Guide List

2007-09-04T13:55:00.000-07:00

This is the list of possible Sherpa Guides for Cycle 1 of blogging. Pick our next Sherpa from this list. If a classmate has served as a Sherpa Guide then their name will be crossed off. Choose one of the names that hasn't been crossed off.

updated Nov. 20, 2007
~~Jaclyn~~
~~Jesse~~
KellyP
~~KellyS~~
~~Kerrie~~
Kimberly
Kristyn
Marc
~~Maria~~
Mia
Nicole
Saad
Seung
~~Shana~~
Shannah
~~Tom~~

Welcome to Our Virtual Classroom

2007-09-03T14:57:00.000-07:00

We started blogging this summer, but now we are going to take it to the next level. This will be your blog for AP Biology (Period 8 & 9) for the whole year. Let me make that clear -- this isn't MY blog; this is OUR blog. This blog is what you'll make of it. I'll prod a bit to get you started, but you can then take it as far as you want, to make it a helpful learning environment for all of you.

Since I strongly believe that you don't really learn something until you have to teach it to someone else, we will use this blog for students to teach students. Each day a student in class will be assigned to be the class sherpa -- our guide who will show us the clear path up the mountain of knowledge. I will appoint the first sherpa, but after that... today's sherpa will pass their baton on to the next sherpa of their choosing. This will serve as 50% of your participation mark for the quarter.

What will the sherpa do here?

Summarize the day's lesson.
Highlight the important points of the lesson -- especially highlighting concepts exemplifying the 8 themes of biology (more about these later).
Highlight any unanswered questions left after the class.
Help clarify any points of confusion left after class.
Point us to resources that help learn today's lesson -- like animations, videos, diagrams, photos, other teacher's Web sites that illustrate concepts we've been learning.