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What is a Protist?. Unicellular or multicellular Microscopic or very large Heterotrophic or Autotrophic What do they have in common? All protists are eukaryotic , meaning they have membrane bound organelles. (like us!) Live in moist environments.
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What is a Protist? • Unicellular or multicellular • Microscopic or very large • Heterotrophic or Autotrophic • What do they have in common? • All protists are eukaryotic, meaning they have membrane bound organelles. (like us!) • Live in moist environments. • Categorized by their method of nutrition. http://www.youtube.com/watch?v=SCfg3sywC7k
Animal-like Protists • Called protozoa (protozoan singular) • All protozoa are unicellular • Heterotrophic • Are grouped on how they move • Cilia (Ciliates) • Reproduce asexually and use its cilia, oral groove, gullet and food vacuoles in the process of digestion • Flagella (Flagellates) • African Sleeping sickness, help termites digest wood • Cytoplasm containing pseudopodia (Amoeboid) • Amoebas reproduce asexually and can form cysts in extreme conditions • One group causes disease called sporozoans • Most produce spores (a reproductive cell that forms without fertilization and produces a new organism) • Parasites • 300 Million people globally have Malaria • Examples: • Paramecium • Foraminiferans • Amoebas http://www.youtube.com/watch?v=F_Xi3hnhtbg
Fungus-like Protists Ewww.. we’re gross! Dude, I know. • Decompose dead organisms • Heterotrophic / Decomposers • Unlike Fungi… • Can move around during some point in their life • Do not have chitin in their cell walls • Examples: • Slime Molds • Water Molds • Downy Mildews http://www.youtube.com/watch?v=9pNGhW9BiZE
http://www.youtube.com/watch?v=0rNI8Bos_BQ&feature=related Plant-like Protists • Called algae (alga singular) • Do not have organs like roots, stems and leaves • Produce most of the Oxygen in the atmosphere and the basis for aquatic food chains. • Undergo the process of photosynthesis to make their own food (Autotrophic) • Note: Euglena can also be heterotrophic • Examples: • Euglena • Diatoms (silica shells) • Dinoflagellates (red tides) • Red, Brown, Green algae • Green algae were likely ancestral plants.
Plant-like Protists:Alternation of Generations • The life cycles of some algae and all plants have a pattern called alternation of generations. • Alternates between haploid and diploid generations • Haploid form is called the gametophyte because it produces gametes. • The gametes fuse to form a zygote which form the diploid part of the organism is called the sporophyte. • Eventually these cells become haploid spores that can develop into a new gametophyte. http://biology.clc.uc.edu/courses/bio106/protista.htm