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 Sporozoans 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 Diatoms – 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 Brown 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 Uses 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 Ecological effects 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