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Kingdom Protista

Kingdom Protista. Kingdom Protista. Kingdom Protista - 65,000-200,000 species (est.), fr. Greek protos = first, ktistos = established - algae, protozoans Also called Kingdom Protoctista Taxonomic “grab bag”, primitive organisms only distantly related (polyphyletic). Kingdom Protista.

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Kingdom Protista

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  1. Kingdom Protista

  2. Kingdom Protista • Kingdom Protista - 65,000-200,000 species (est.), fr. Greek protos = first, ktistos = established - algae, protozoans • Also called Kingdom Protoctista • Taxonomic “grab bag”, primitive organisms only distantly related (polyphyletic)

  3. Kingdom Protista • All protists are eukaryotes • All protists are aquatic • Unicellular or multicellular • Some are colonial - cells specialize in different function (feeding, reproduction) = division of labor, communication

  4. Kingdom Protista • Some are autotrophs = algae • Some are heterotrophs = protozoa • Reproduce either sexually or asexually (by binary fission) • Complex life cycles

  5. Kingdom Protista • Protists are so small they don’t need special organs to exchange gas or excrete wastes • They rely on diffusion - passive movement of molecules from area of higher concentration to area of lower concentration • Diffusion results from the random movement of molecules

  6. Kingdom Protista • Diffusion is a two edged sword • Protists don’t need to invest in complex respiratory or excretory tissue • They have to stay tiny - diffusion only works if you’re very small • Most protists are single cells

  7. Kingdom Protista • Size is also limited by means of locomotion • Many protists are propelled by cilia or flagella, tiny movable hairs • Protists eat by phagocytosis • Engulf food in cell membrane • Pinch off membrane to form a vacuole • Vacuoles store food, water, enzymes, wastes

  8. Phagocytosis

  9. Didinium devours Paramecium

  10. Kingdom Protista • All of these traits are primitive - similarities may be due to convergent evolution • Protists are mainly defined by what they are not • Not bacteria, archaea, or fungi… • Not plants or animals…

  11. Kingdom Protista • Protists gave rise to all other plants and animals • Phylogeny of protists still a real mess • We assume they rose from certain groups of archaeans, but which?

  12. Kingdom Protista • Protists are so different from one another, most may represent several early independent lineages of eukaryotes • First evolved ~ 1.2 billion years ago • As many as 50 phlya recognized • We’ll focus on several typical phyla

  13. Kingdom Protista • Protozoa - heterotrophs • Motile • Cilia – Ciliophora • Flagella – Dinoflagellata, Euglenozoa • Pseudopodia – Amoebozoa, Foraminifera • Non- motile - Apicomplexa • Gave rise to higher animals

  14. Kingdom ProtistaPhylum Euglenozoa • 800 sp. - Euglena • Plant or animal? Heterotrophs, but 1/3d are also photosynthetic • May have formed by endosymbiosis, engulfed green algae cell

  15. Euglena

  16. Euglena

  17. Kingdom ProtistaPhylum Dinoflagellata • Dinoflagellates - 3,000 species, fr. Greek dinos = whirling, Latin flagellum = whip - Ceratium, Gonyaulax • About half are photosynthetic

  18. Dinoflagellates

  19. Kingdom ProtistaPhylum Dinoflagellata • Two flagella, one like a belt, one like a tail • Many have armor of cellulose plates encrusted with silica

  20. Dinoflagellates

  21. Kingdom Protista Phylum Dinoflagellata • Importance • Zooxanthellae, dinoflagellates that have lost flagella & armor, live as symbionts in mollusks, sea anemones, jellyfish, coral • Make coral more productive, limits coral to shallow water

  22. Kingdom Protista Phylum Dinoflagellata • Importance • Algal blooms of dinoflagellates are the cause of red tide - 20 species produce potent toxins • 1987 outbreak killed half the Western Atlantic population of bottlenose dolphin! • Could make La. oysters an unforgettable experience…

  23. Red Tide 2010 Breton-Chandeleur

  24. Kingdom ProtistaPhylum Apicomplexa • Apicomplexa are spore-forming parasites • One end has an apical complex, apparatus designed to let them invade a host cell • Sometimes called sporozoans, many form non-motile spores

  25. Kingdom ProtistaPhylum Apicomplexa • Plasmodium – causes malaria • Spores are passed from one host to the next by vectors (mosquitoes etc.) • Typical parasite life cycle, with intermediate hosts

  26. Kingdom ProtistaPhylum Ciliophora • 8,000 species, fr. Latin cilium = eyelash, Greek phorein = to bear - Paramecium, Blepharisma • Complex little critters - many organelles and specialized structures

  27. Blepharisma

  28. Kingdom Protista • Paramecium (and many other protists) have a contractile vacuole • Complex vacuole that drains wastes from the cell

  29. Contractile Vacuole of Paramecium

  30. Kingdom ProtistaPhylum Ciliophora • Move by numerous cilia • Many ciliophorans defend themselves by discharging little toxic threads or darts

  31. Paramecium, with cilia stained

  32. Kingdom ProtistaPhylum Ameobozoa • Over 300 species – true amoeba • Move by pseudopods - extend part of cell to form a “false foot”, then flow into it (cytoplasmic streaming) • Eat other protozoans, algae, even tiny multicellular creatures

  33. Amoeba

  34. Kingdom Protista Phylum Ameobozoa • Many amoeba are parasites • Entamoeba histolyca - amoebic dysentery, infects ~10 million Americans, 50% of population in the tropics

  35. Kingdom Protista Phylum Ameobozoa • Many amoeba are parasites • Primary Ameobic Meningoencephalitis (PAM) Naegleria fowleri enters the nostrils (frequently during swimming), attacks the brain, can be fatal within one week of symptoms • PAM is relatively rare -120 U.S. cases in 25 years

  36. Kingdom Protista Phylum Ameobozoa • PAM cases include two people in La. in 2011 who died from nasal irrigation with infected water (has to go way up the nose) • PAM killed a 4 year old child in LA in 2013 who got it from playing on a Slip ‘n Slide • Later found in the municipal water supply in Arabi and Violet (a first) – easily killed by chlorination

  37. Kingdom Protista Phylum Foraminifera • Foraminifera • Marine forms, sculpted shells (calcium carbonate) • Extend cytoplasmic podia out along the spines • Spines function in feeding, swimming

  38. Kingdom Protista Phylum Foraminifera • Importance • So abundant, they formed most of the world’s limestone, marble, and chalk • Great Pyramids composed of billions upon billions of foraminiferan shells • Abundant in fossil record, used by geologists to help identify layers of rock - indicator species

  39. Foraminiferan shells

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