Wednesday, October 10, 2007

Protists & plants!

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:

  • 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)

  1. amoeba
  2. paramecium
  3. stentor

plant-like protists ( autotrophs)

  1. euglena
  2. algae
  3. diatoms


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.


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. =]

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