1. Protists

2. What is a protist? All (some say the first) eukaryotes They are a very diverse group Most are unicellular Many are multicellular Many are microscopic –A single cell can be 1 meter long Autotrophs and heterotrophs Sexual and asexual reproduction

3. Classification Based on what the organism is not!!! If you are eukaryotic and not a fungus, plant or animal Then you are a protist… Active field of systematics, cladistics and taxonomy

4. Evolution again Evolution of eukaryotes –Appearance of internal membranes –Appearance of symbiosis (mutualism) Do you remember “endosymbiont”?

5. Evolution of sexual reproduction Chromosome shuffling during meiosis Crossing over during meiosis Leads to increase in genetic variation Remember all this???

6. Autotrophic Protists Algae Perform 40% of the photosynthesis on earth Red algae, green algae, brown algae

7. Heterotrophic Protists Commonly called protozoans Most are unicellular Can be predators, decomposers or parasites

8. Four Phyla of Protozoans Based on how they move Use flagella (Flagellates, Zoomastigina) Example: Trichonympha in Termite gut Example: Typanosoma causes African sleeping sickness Illustration on page 607

9. Four Phyla of Protozoans Based on how they move Use pseudopods, “false feet” (Sarcodines, Sarcodina) Example Ameba Example Forams (Foraminifera) Illustration on page 606

10. Four Phyla of Protozoans Based on how they move Use cilia “short hairs” (Ciliates, Ciliophora) Example Paramecium Ciliates have: –Micronucleus and macronucleus –Contractile vacuole (osmosis) –Gullet, anal pore, trichocysts –Binary fission normally, conjugation when stressed Illustration on page 607

11. Four Phyla of Protozoans Based on how they move Use nothing, i.e., don’t move (Sporozoans, Sporozoa) Example Plasmodium Causes malaria, uses two hosts –Mosquitoes and birds or mammals

12. Fungus-like Protists Slime molds Life mostly as solitary creatures, looks ameba-like In stress attracts others to form a giant mass Produces fruiting body cells Produces spores and disperse the spores in the wind

13. Protist Reproduction No generic life cycles Most use sexual reproductive strategies Algae show alternation of generations –One generation is diploid (sporophyte) –Next generation is haploid (gametophyte) –Next generation is diploid and so on…..