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Protists

Protists. Kingdom Protista. Overview of the history of life. 4.5 BYA – Earth formed 3.5 BYA – Prokaryotes were abundant 3.0 BYA – Eubacteria and Archaea split 2.5 BYA – oxygen revolution with lots of cyanobacteria 1.5-1.7 BYA – eukaryotes evolve, these are protists

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Protists

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  1. Protists Kingdom Protista

  2. Overview of the history of life • 4.5 BYA – Earth formed • 3.5 BYA – Prokaryotes were abundant • 3.0 BYA – Eubacteria and Archaea split • 2.5 BYA – oxygen revolution with lots of cyanobacteria • 1.5-1.7 BYA – eukaryotes evolve, these are protists • 1 BYA – protists colonize to form multicellular organisms (seaweeds)

  3. Protists • More diverse than any other kingdom • All are eukaryotes • We’ll look at: • Protozoans(animal-like protists) • Algae (plant-like prostists) • Slime molds (fungus-like protists)

  4. Protozoans • Animal-like protists • Have movement • Heterotrophs • Unicellular • 4 kinds – Amoebas, zooflagellates, ciliaphorans, sporozoans

  5. Protozoan

  6. Amoebas • Move and eat by using pseudopods • Pseudopods – lobes of cytoplasm used to move and eat. • Live in fresh and ocean water • Extremely flexible, creep over rocks and sticks at the bottom of lakes or oceans • Some protozoans with pseudopods have hard shells – forams

  7. Amoeba

  8. Zooflagellates • Zooflagellates – Move by means of flagella • live in fresh water and ocean • Ex. Euglena, Giardia (diarrhea), trypanosoma (African sleeping sickness)

  9. Euglena

  10. Giardia

  11. Trichonympha

  12. Trypanosoma

  13. Ciliaphorans • Ciliates – protozoans that move and feed with short hair-like projections called cilia. • Ex. Paramecium – freshwater ciliate covered with a tough pellicle. • It holds food with food vacuoles • Paramecium uses an anal pore to eject waste and a contractile vacuole to release water.

  14. Paramecium

  15. Paramecium reproducing

  16. Sporozoans • Spore-forming protozoans • Spore- an asexual reproductive cell that can remain dormant or develop into a new organism • Covered by thick, sporelike walls • Plasmodium – causes malaria

  17. Habitat • Part of plankton in fresh and ocean water • Found in wet soil, leaf litter, and other decaying matter on a forest floor • Important in the food chain, feed on bacteria, yeast, algae • Can be scavengers (decomposers) and parasites

  18. Algae • Algae – plant-like protists that perform photosynthesis • Some are multicellular, some are unicellular • Algae are important because they provide food for other organisms and they provide oxygen through photosynthesis.

  19. Unicellular Algae Dinoflagellates - protists with two flagella that propel them through the water like a top. • Mostly salt water • Live symbiotically with jellyfish and coral Diatoms – protists with silica cell walls that lack flagella • Very beautiful, important in making diatomaceous earth for cleaners, abrasives, toothpaste, asphalt • Float on the sun-lit surfaces of ponds, lakes, and oceans

  20. Unicellular Algae Green Algae • Most closely related to plants of all protists • Live mostly in fresh water and soil, some in ocean • Ex. Volvox, Ulva

  21. Diatom

  22. Dinoflagellate

  23. Diatom

  24. Volvox

  25. Multicellular Algae Red Algae • Live mostly in warm saltwater • Red pigments trap sunlight • Reproduce by alternation of generations- alternation between sexual and asexual reproduction Brown Algae • Cool saltwater • Kelps-provide food and shelter for other organisms; among the largest organisms on Earth • Reproduce by alternation of generations

  26. Red Algae

  27. Kelp Forest

  28. Importance of Algae • Phytoplankton – perform photosynthesis; algae that drift passively at the surface of an aquatic environment • An important food source for many marine organisms

  29. Funguslike protists • Important decomposers Plasmodial Slime Molds – form a mass of cytoplasm called a plasmodium • Live around rocks and logs • Can become dormant when conditions are unfavorable (form spores) • Sexual reproduction (haploid spores fuse into diploid zygotes) Cellular Slime molds – live in fresh water and wet soil; form colonies called slugs Water Molds – mildews and shower mold

  30. Plasmodial Slime Mold

  31. Cellular Slime Mold

  32. Extra Credit Question 1 • What is the name of the structure that amoebas use to eat and move?

  33. Extra Credit Question 2 • What are the three categories of protists?

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