ProtistsProtistsChapter 20

Any organism that is not a plant, animal, fungus, or bacteria.

All EukaryotesMost are unicellular; a few

multicellularClassify according to method of

nutrition◦Animal-like – heterotrophs◦Plant-like – photoautotrophs◦Fungus-like – decomposers

Protozoans – animal-likeProtozoans – animal-likeGrouped by how they moveZooflagellates

◦ 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.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.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.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-likeAlgae – plant-likeGrouped by type of

photosynthetic pigmentsAre 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.Algae cont.Chrysophytes – unicellular

◦Gold-colored chloroplasts◦Ex. Yellow-green algae,

golden-brown algaeDiatoms – unicellular

◦Box-like shells of silicaDinoflagellates – unicellular

◦2 flagella◦Autotrophs and heterotrophs◦Bioluminescent◦Release toxins – produce red

tide

Algae cont.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.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 protistsFungus-like protistsSimilar to fungi – are decomposersDifferent from fungi – lack chitin cell

wallsSlime 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.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