Protists

Characteristics: eukaryotic mostly unicellular may be plant-like, animal-like, or fungus-like in mode of nutrition (how they get food)

A. Animal-like protists protozoans – “first animals” heterotrophic classified by locomotive structures (how they move)

Animal-like protists Phylum Ciliophora – ciliates -move by cilia – short, bristle-like structures for locomotion -use cilia to sweep in food -most free-living, some parasitic -ex: Paramecium (see p. 469)

Animal-like protists Phylum Sarcodina -move by pseudopods – “false feet”, by pushing cytoplasm in certain direction -have no definite shape -uses pseudopods to get food by phagocytosis -ex: Amoeba, radiolarians, heliozoans, foraminiferans see p. 464

Animal-like protists Phylum Zooflagellata – zooflagellates -use flagella – whiplike tails for locomotion -many parasitic; get food by absorption or phagocytosis -ex: Trichonympha – lives in termite gut Trypanosoma – lives in Tsetse fly; causes African sleeping sickness

Animal-like protists Phylum Sporozoa -all parasitic -no locomotion -complex life cycles with more than one host -ex: Plasmodium – causes malaria

B. Plant-like protists algae autotrophic by photosynthesis contain chlorophyll classified by cell wall components

Plant-like protists Phylum Euglenophyta -use flagella or crawl in “euglenoid movement” -has flexible pellicle – thick membrane for protection -lives in fresh or salt water -photosynthetic, but if no light available, can be heterotrophic -no cell wall -ex: Euglena (see p. 467)

Plant-like protists Phylum Pyrrophyta – “fire algae” -use 2 flagella -have thick, armored plates -most marine (salt water) dwellers -cellulose cell walls -many are luminescent – give off light -ex: dinoflagellates – cause red tide

Plant-like protists Phylum Chrysophyta – golden algae -solitary or colonial -float in water -contain oil as food storage -marine or fresh water -cell walls of silica -ex: diatoms – used in toothpaste (see p. 466)

C. Fungus-like protists Phylum Acrasiomycota – cellular slime molds -complex life cycles -food by phagocytosis/absorption -independent cells that work together to form asexual reproductive structures -cellulose cell walls -ex: Dictyostelium (see p. 470)

Fungus-like protists 2) Phylum Myxomycota – plasmodial slime molds -food by phagocytosis/absorption -produce structures called plasmodia that have thousands of nuclei in one large cell and crawls around to get food -ex. Physarum

How do protists affect us? Beneficial decomposers major food source in aquatic food chains used as abrasives in toothpaste food source used in many foods

How do protists affect us? Harmful cause disease (malaria, African sleeping sickness) cause red tide kill crops