Protists

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Protists
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Characteristics

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

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A. Animal-like protists

• protozoans first animals
• heterotrophic
• classified by locomotive structures (how they
  move)

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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)

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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

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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

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Animal-like protists

• Phylum Sporozoa
• -all parasitic
• -no locomotion
• -complex life cycles with more than one host
• -ex Plasmodium causes malaria

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B. Plant-like protists

• algae
• autotrophic by photosynthesis
• contain chlorophyll
• classified by cell wall components

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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)

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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

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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)

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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)

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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

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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

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How do protists affect us?

• Harmful
• cause disease (malaria, African sleeping
  sickness)
• cause red tide
• kill crops