Transcript Protists - TeacherWeb

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
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Protozoans – animal-like
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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.
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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)
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Sporozoans
◦ Parasites - Do not move on their own
◦ Complex life cycles w/ more than one host
Protozoans cont.
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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.
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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
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◦ 2 flagella
◦ Heterotrophic if no sun
Algae cont.
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Chrysophytes – unicellular
◦ Gold-colored chloroplasts
◦ Ex.Yellow-green algae,
golden-brown algae
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Diatoms – unicellular
◦ Box-like shells of silica
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Dinoflagellates – unicellular
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2 flagella
Autotrophs and heterotrophs
Bioluminescent
Release toxins – produce red
tide
Algae cont.
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Red algae – multicellular
◦ Contain phycobilins (absorb blue light) which
allow them to live at great depths
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Brown algae – multicellular
◦ Contain fucoxanthin – brown pigment
◦ Largest
◦ Ex. kelp
Algae cont.
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Green algae
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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
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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.
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Water molds
◦ Live on dead material
in water or as plant
parasites
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Ecological effects
◦ Decomposers
◦ Mildews and blights on plants
◦ Ex. Phytophthora infestans – caused the Irish
potato famine