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Protists Chapter 20 Any organism that is not a plant, animal, fungus, or bacteria. All Eukaryotes Most are unicellular; a few multicellular Classify according to method of nutrition ◦ Animal-like – heterotrophs ◦ Plant-like – photoautotrophs ◦ Fungus-like – decomposers Protozoans – animal-like Grouped by how they move Zooflagellates ◦ Swim w/ flagella (most have 1 or 2) ◦ Absorb nutrients through cell membrane Sarcodines ◦ Use pseudopodia (cytoplasmic extensions) to move and feed – aka amoeboid movement ◦ Feed by surrounding food w/ pseudopodia and forming a food vacuole around it ◦ Ex. Amoebas, heliozoans ◦ Ex. Foraminiferans – have shells of calcium carbonate – White Cliffs of Dover, England Protozoans cont. Ciliates ◦ Use cilia (hairlike projections) to move ◦ Ex. Paramecium – has a macronucleus (uses every day) and a micronucleus (a reserve copy of all the genes) Sporozoans ◦ Parasites - Do not move on their own ◦ Complex life cycles w/ more than one host Protozoans cont. Diseases ◦ Malaria – caused by sporozoan Plasmodium Carried by female Anopheles mosquito In human – infects liver cells where it moves to red blood cells – causes rbcs to burst = chills and fever ◦ African sleeping sickness – caused by zooflagellate Trypanosoma Carried by tsetse fly Infects nerve cells = unconsciousness ◦ Amebic dysentery – caused by sarcodine Entamoeba – Invade intestines Protozoans cont. Ecological importance ◦ Break down organic matter, provide food for small aquatic animals ◦ Trichonympha – lives in guts of termites Breaks down cellulose in wood for termite to digest Algae – plant-like Grouped by type of photosynthetic pigments Are found in phytoplankton – carry out ½ of the photosynthesis on Earth & provide nourishment for many ocean creatures Euglenophytes – unicellular ◦ 2 flagella ◦ Heterotrophic if no sun Algae cont. Chrysophytes – unicellular ◦ Gold-colored chloroplasts ◦ Ex.Yellow-green algae, golden-brown algae Diatoms – unicellular ◦ Box-like shells of silica Dinoflagellates – unicellular ◦ ◦ ◦ ◦ 2 flagella Autotrophs and heterotrophs Bioluminescent Release toxins – produce red tide Algae cont. Red algae – multicellular ◦ Contain phycobilins (absorb blue light) which allow them to live at great depths Brown algae – multicellular ◦ Contain fucoxanthin – brown pigment ◦ Largest ◦ Ex. kelp Algae cont. Green algae ◦ ◦ ◦ ◦ uni/multicellular; some colonial Cell walls of cellulose Fresh/salt water Ex. Ulva (sea lettuce), volvox Uses ◦ Treat stomach ulcers, arthritis ◦ Food – wrap sushi, ice cream, pudding, salad dressing, eggnog, pancake syrup ◦ Industry – paints, plastics, transistors Fungus-like protists Similar to fungi – are decomposers Different from fungi – lack chitin cell walls Slime molds ◦ Like damp places rich with organic matter ◦ Cellular slime molds Have distinct cell membranes ◦ Plasmodial slime molds No cell membranes Form a plasmodium with many nuclei Fungus-like cont. Water molds ◦ Live on dead material in water or as plant parasites Ecological effects ◦ Decomposers ◦ Mildews and blights on plants ◦ Ex. Phytophthora infestans – caused the Irish potato famine
