Published on

1 Comment
No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide


  1. 1. Protists Classifying the Exceptions
  2. 2. What are Protists? <ul><li>Those organisms that cannot be classified as Monerans, fungi, plants or animals </li></ul><ul><li>Created as a group because of classification problems </li></ul><ul><li>Some share characteristics of more than one other kingdom </li></ul><ul><li>Example: </li></ul><ul><ul><li>Euglena has chloroplasts & is an autotroph like plants, </li></ul></ul><ul><ul><li>but has no cell wall and can swim using a flagella, so also like an animal </li></ul></ul>
  3. 3. Characteristics of Protists <ul><li>Almost all are unicellular </li></ul><ul><ul><li>A few are colonies of identical cells </li></ul></ul><ul><li>Are distinguished from unicellular Monerans because they are eukaryotes </li></ul><ul><ul><li>Have a nuclear membrane </li></ul></ul><ul><ul><li>Have mitochondria and other organelles </li></ul></ul><ul><li>A diverse group with diverse characteristics </li></ul><ul><ul><li>some are plant-like, autotrophs  algae </li></ul></ul><ul><ul><li>some are animal-like, heterotrophs  protozoans </li></ul></ul><ul><ul><li>some are fungus-like, decomposers  slime molds </li></ul></ul>
  4. 4. Plant-like Protists <ul><li>10,000 species of plant-like protists </li></ul><ul><li>Divided into 3 phyla </li></ul><ul><ul><li>Phylum Euglenophyta </li></ul></ul><ul><ul><li>Phylum Pyrrophyta </li></ul></ul><ul><ul><ul><li>dinoflagelates, plankton </li></ul></ul></ul><ul><ul><li>Phylum Chrysophyta </li></ul></ul><ul><ul><ul><li>diatoms </li></ul></ul></ul>
  5. 5. Phylum Euglenophyta <ul><li>Most have chloroplasts - are autotrophs </li></ul><ul><li>Have a large nucleus and nucleolus </li></ul><ul><li>Have large chloroplasts </li></ul><ul><ul><li>these disappear if the organism is placed in the dark </li></ul></ul><ul><li>No cell wall </li></ul><ul><ul><li>on the outer surface of the cell are spiral strips of protein which form a pellicle - give cell shape </li></ul></ul><ul><li>Can move by changing shape </li></ul><ul><li>Have 2 flagella: one long, one short </li></ul><ul><li>Have an eye spot </li></ul><ul><ul><li>an area of red pigment that is sensitive to light </li></ul></ul><ul><li>A gullet opens into reservoir </li></ul><ul><li>Reproduce asexually </li></ul>
  6. 6. Euglenoids
  7. 7. Freshwater Protists <ul><li>Euglenoids live in fresh water ponds and lakes </li></ul><ul><ul><li>The single-celled organism is in a hypotonic solution </li></ul></ul><ul><ul><li>Water diffuses in by osmosis </li></ul></ul><ul><li>No rigid cell wall </li></ul><ul><li>These organisms have to have an other means to prevent the cell membrane from bursting </li></ul><ul><li>Contractile vacuole controls water balance </li></ul><ul><ul><li>Pumps excess water back out of the cell </li></ul></ul>
  8. 8. The Contractile Vacuole
  9. 9. Phylum Pyrrophyta <ul><li>Most common are dinoflagellates </li></ul><ul><li>Unicellular algae with 2 flagella  </li></ul><ul><li>Most are marine </li></ul><ul><ul><li>Many plankton (small organisms near the surface of the ocean) are dinoflagelates </li></ul></ul><ul><li>Mitosis is somewhat like prokaryotes </li></ul><ul><ul><li>some scientists believe are intermediate form between prokaryotes and eukaryotes </li></ul></ul>
  10. 10. Dinoflagellate Characteristics <ul><li>Most have chloroplasts with chlorophyll </li></ul><ul><ul><li>red & yellow pigments mask the green </li></ul></ul><ul><li>Most have a cellulose cell wall </li></ul><ul><li>Segments fit together like armor </li></ul><ul><li>Most have 2 flagella </li></ul><ul><ul><li>One extends back from the middle of the cell - propels the organism </li></ul></ul><ul><ul><li>2nd wraps around middle in a groove - vibrates causing cell to spin </li></ul></ul><ul><li>Chromosomes are visible in dinoflagellates </li></ul><ul><li>Some produce toxins - red tide! </li></ul><ul><li>Many produce light - bioluminescence </li></ul>
  11. 11. A Dinoflagellate
  12. 12. Phylum Chrysophyta <ul><li>Most are diatoms - live in fresh and salt water </li></ul><ul><li>Most are photosynthetic </li></ul><ul><ul><li>Most are gold or brown from pigments other than chlorophyl </li></ul></ul><ul><li>Most don't have flagella </li></ul><ul><li>Have cell walls with 2 overlapping halves </li></ul><ul><ul><li>composed of pectin - a gelatinous material; also contains silica </li></ul></ul><ul><li>Reproduce a sexually </li></ul>
  13. 13. Diatoms
  14. 14. Multi-cellular Algae <ul><li>Many algae have multi-cellular bodies </li></ul><ul><ul><li>Body of a multi-cellular algae = thallus </li></ul></ul><ul><li>Once classified as plants because they have chlorophyll and perform photosynthesis </li></ul><ul><li>Now usually classified as protists because they have reproductive structures different from plants </li></ul><ul><li>Three phyla: </li></ul><ul><ul><li>Chlorophyta = green algae </li></ul></ul><ul><ul><li>Rhodophyra = red algae </li></ul></ul><ul><ul><li>Phaeophyta = brown algae </li></ul></ul>
  15. 15. Red Algae
  16. 16. Volvox – A Colonial Green Algae
  17. 17. Spirogyra Conjugation
  18. 18. Kelp – A Brown Algae
  19. 19. Protozoans <ul><li>Animal-like protists </li></ul><ul><ul><li>Are heterotrophs </li></ul></ul><ul><ul><li>Can move </li></ul></ul><ul><li>Classified by their means of movement </li></ul><ul><li>Four diverse groups: </li></ul><ul><ul><li>Sarcodinians </li></ul></ul><ul><ul><li>Zooflagellates </li></ul></ul><ul><ul><li>Ciliaphorans </li></ul></ul><ul><ul><li>Sporozoans </li></ul></ul>
  20. 20. Sarcodinians <ul><li>Protozoans that move by extending lobes of cytoplasm </li></ul><ul><ul><li>Pseudopods = false feet </li></ul></ul><ul><li>Example: amoeba </li></ul><ul><li>Some have hard shells of calcium carbonate or silica </li></ul><ul><ul><li>Extend pseudopods through holes in their shells </li></ul></ul><ul><li>Examples: foraminferans & radiolarians </li></ul>
  21. 21. The Amoeba
  22. 22. Radiolarian
  23. 23. Heliozoan
  24. 24. Zooflagellates <ul><li>Protozoans that move by means of a flagella </li></ul><ul><li>Many are free-living freshwater or marine organisms </li></ul><ul><li>Many live in symbiotic relationships with other organisms </li></ul><ul><ul><li>Example: Trichonympha live in the guts of termites and digest cellulose </li></ul></ul><ul><li>Some are parasites that cause disease </li></ul><ul><ul><li>Example: Trypanosoma causes African sleeping sickness </li></ul></ul>
  25. 25. Trypanosomes
  26. 26. Trichomona
  27. 27. Ciliaphorans <ul><li>Protozoans covered with hair like projections, cilia, used to move </li></ul><ul><li>The largest and most diverse group </li></ul><ul><li>Examples: </li></ul><ul><ul><li>Paramecium </li></ul></ul><ul><ul><li>Stentor </li></ul></ul>
  28. 28. The Paramecium
  29. 29. Sporozoans <ul><li>Have no structures for movement </li></ul><ul><li>Live as parasites on other animals </li></ul><ul><ul><li>Spore-forming parasitic protozoans </li></ul></ul><ul><li>Have complex life cycles that include both sexual and asexual phases </li></ul><ul><li>Some cause human diseases </li></ul><ul><ul><li>Example: plasmodium causes malarial carried by mosquitos </li></ul></ul>
  30. 30. Fungus-like Protists <ul><li>Live in damp, watery places </li></ul><ul><li>Decomposers </li></ul><ul><li>Extract nutrients from dead organisms </li></ul><ul><li>Three groups: </li></ul><ul><ul><li>Plasmodial slime molds </li></ul></ul><ul><ul><li>Cellular slime molds </li></ul></ul><ul><ul><li>Water molds </li></ul></ul>
  31. 31. Plasmodial Slime Molds <ul><li>Have different forms at different stages in their life cycle </li></ul><ul><li>Plasmodium = feeding stage </li></ul><ul><li>Forms a fruiting body that produces spores </li></ul><ul><li>Spores unite to form amoeboid zygote  the second stage </li></ul><ul><li>Mitosis of the zygote regenerates the plasmodium </li></ul>
  32. 32. Slime Mold
  33. 33. Cellular Slime Molds <ul><li>Live in fresh water, damp soil, or decomposing plant material </li></ul><ul><li>Also alternate between an amoeboid form and a spore-producing fruiting body </li></ul><ul><li>Amoeboid stage is the feeding stage </li></ul><ul><ul><li>Reverse of plasmodial slime molds </li></ul></ul><ul><li>Amoeboid stage can produce a pseudoplasmodium </li></ul><ul><ul><li>“ Pseudo” because the individual cells are still independent </li></ul></ul><ul><li>Pseudoplasmodium produces fruiting bodies </li></ul><ul><li>Fruiting bodies produce spores </li></ul>
  34. 34. Water Molds <ul><li>Used to be classified as fungi </li></ul><ul><ul><li>Fungi have cell walls that contain chitin </li></ul></ul><ul><ul><li>Water molds have cell wall of cellulose </li></ul></ul><ul><ul><li>Water molds produce spores with flagella </li></ul></ul><ul><ul><li>Fungi produce spores without flagella </li></ul></ul><ul><li>Are decomposers or parasites </li></ul><ul><li>Includes water molds, white rusts, downy mildews </li></ul><ul><ul><li>Potato blight </li></ul></ul>
  35. 35. Powdery Mildew