Tuesday, December 11, 2007

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!!

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
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..
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?

Sunday, December 9, 2007

nervous systems- Brain development

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 ??

Wednesday, December 5, 2007

The Nervous System (cont.)

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.

Tuesday, December 4, 2007

Kidney's yey!!

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

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).

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

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:

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


Sunday, December 2, 2007

Regulating the Internal Environment

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

Tuesday, November 27, 2007

The Cell Membrane

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

Wednesday, November 21, 2007


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.


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


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.


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!)


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.


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.


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.


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.

Monday, November 19, 2007

A Tour of the Cell

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


Sunday, November 18, 2007

Nucleic Acids

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 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!

Thursday, November 15, 2007


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.


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.

Sunday, November 11, 2007

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.


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 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:

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!

Saturday, November 10, 2007

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.


Wednesday, November 7, 2007

The Chemistry of Life

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.

Thursday, November 1, 2007

Animal Behavior (cont...)

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.


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.

Tuesday, October 30, 2007

Ethology and Isopods

- 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)
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.


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:

Waggle Dance:


Tomorrows Sherpa is Marc

Monday, October 29, 2007

Earth's biomes

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.


>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.


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.



Tomorrow's Sherpa is Shannah =]

Thursday, October 25, 2007

Community Ecology: Part III


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.

Wednesday, October 24, 2007

Community Ecology: Part DUEX.

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 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!