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Protists

Protists. Characteristics. Most diverse kingdom eukaryotic., 1.5 bya Primarily unicellular/multicellular, heterotrophic/autotrophic Usually asexual, some sexual Found in water, damp soil and sand, leaf litter Some are parasitic 14 phyla. Characteristics.

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Protists

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  1. Protists

  2. Characteristics • Most diverse kingdom • eukaryotic., 1.5 bya • Primarily unicellular/multicellular, • heterotrophic/autotrophic • Usually asexual, some sexual • Found in water, damp soil and sand, leaf litter • Some are parasitic • 14 phyla

  3. Characteristics • Characteristics first seen in Protista kingdom • Sexual reproduction (varies, mitosis and meiosis – usually in harsh enviro.) • Multicellularity (coordination among specialized cells) • Complex flagella and cilia (as opposed to simple seen in bacteria)

  4. Protist diversity • Heterotrophic protists = protozoans, slime molds, parasites • Photosynthetic protists = Algae • Some are classified further by how they move: • Amoebas – pseudopodia • Ciliates – cilia, ex. paramecium • Flagellates – flagella, ex. Euglena

  5. Amoeba • Pseudopodia – false foot, cytoplamsic extensions • Food vacuole – food enters and moves throughout cell • Contractile vacuole – regulates water

  6. Diatoms • Photosynthetic • Double shell made out of silica • Move by excreting chemicals through holes in shell • Found in oceans and lakes • Important to food chain • Diatomaceous earth – • abrasives

  7. Algae – Green, Red and Brown • Strict autotrophs, some multicellular • Distinguished by type of pigment they contain • Red • Multicellular, warm ocean waters • Red pigment can absorb light in deep water • Brown • Multicellular, marine • Kelp, grows along coasts, food and shelter • Green • Most freshwater, uni and multicellular • Contains chlorophyll a and b

  8. Dinoflagellates • 2 flagella • Unicellular • Most are marine, make up part of the plankton • Some produce powerful toxins – “red tide”

  9. Euglena • Fresh water with 2 flagella • Some photosynthetic with chloroplasts • Pellicle – protein fiber inside cell membrane, allows for flexibility and shape change • Eyespot – light sensitive organ, toward light

  10. Paramecium • Freshwater streams and ponds • Unicellular, heterotrophic • Cilia to move • Two nucluei • Macro – cell activities, includes DNA • Micro –cell reproduction, contains chromosomes

  11. Protistan slime molds • Cellular slime mold • Behave like amoebas • Ingest bacteria • During stress, form multicellular colonies • Plasmodial slime molds • Mass of cytoplasm that looks like ooze • Eat bacteria and other organic material

  12. Sporozoans – parasitic protists • Form spores during their reproductive cycle • Nonmotile, unicellular parasites • Ex. Malaria, caused by Plasmodium parasite • Life cycle page 616, figure 21-14

  13. Beneficial protists • Commensal protists that live in digestive tracts of humans and livestock (hay, cellulose) • Plankton – food, shelter, producers • Largest group of photosynthesizers • Abrasives • Detritivores – recycle chemicals in environment • Symbiotic relationships - coral

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