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PROTISTS

Learn about protists, a diverse group of eukaryotic organisms that include amoeba, paramecium, and euglena. Explore their unique characteristics, such as excretion, reproduction, and classification.

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PROTISTS

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  1. PROTISTS

  2. PROTISTS • COMMON EXAMPLES: • Amoeba, paramecium, euglena, volvox, plasmodium • EUKARYOTIC • Have a nuclear membrane • VERY DIVERSE GROUP • most are unicellular, microscopic, aerobic • Some are autotrophic, heterotrophic, sexual, asexual

  3. PROTISTS • ENDOSYMBIONT THEORY • Early eukaryotes developed symbiotic relationships with prokaryotic cells • Prokaryotic cells lived inside eukaryotic cells • Over time, the smaller prokaryotic cells evolved with the eukaryotic cells to become mitochondria and chloroplasts

  4. PROTISTS • EXCRETION AND OSMOREGULATION • Water balance = osmoregulation • Done by contractile vacuole • Wastes removed by diffusion • RESPIRATION • Carbon dioxide and oxygen diffuse in and out

  5. PROTISTS • REPRODUCTION • Asexual • Mitosis and cytokinesis • Budding – similar to mitosis except daughter cell is smaller than parent • Schizogony – nucleus divides many times and cytoplasm divides to form many daughter cells as there are nuclei

  6. PROTISTS • SEXUALLY • Meiosis – special nuclear division to reduce chromosome number to haploid • Union of gametes = diploid zygote • Syngamy – fertilization between two individuals • Autogamy – two gametes fuse within one organism • Parthenogenesis – development of organism from gamete without fertilization • Conjugation – exchange of nuclear material between two individuals

  7. PROTISTS • DOMAIN EUKARYOTA • KINGDOM PROTISTA • Any eukaryote that is not classified as a fungus, plant, or animal is a PROTIST

  8. PROTISTS • ANIMAL LIKE PROTISTS = PROTOZOA • Classified by method of movement • PLANT LIKE PROTISTS = ALGAE • Classified by pigment color • FUNGUS LIKE PROTISTS = MOLDS • Classified by body form

  9. PROTISTS • PROTIST CLASSFICATION • Separated by feeding habits (nutrition) • Autotrophic • Able to make own food • Photosynthetic – 30-40% of all photosynthesis worldwide is done by algae • Heterotrophic • Must eat other material • Unicellular • May be predators, decomposers, or parasites

  10. PROTISTS • PROTOZOA • Heterotrophic • Unicellular • 4 groups • Sarcodinians • Zooflagellates • Ciliophorans • Sporozoans

  11. PROTISTS • PHYLUM SARCODINA • Aquatic, clear cytoplasm, irregular shape • Move by extending lobes of their cytoplasm • Pseudopods (false feet) • Plasmolemma – elastic cell membrane • Cytoplasm is divided into ectoplasm and endoplasm • Nucleus, contractile vacuole, food vacuole • Example: Amoeba proteus

  12. PROTIST

  13. PROTIST • LABEL THIS AMEOBA

  14. PROTISTS • PHYLUM ZOOMASTIGINA • Often called flagellates because they move using flagella • Absorb food by diffusion through cell membrane • Live off of dead or decaying organic matter or some are parasites • Trichonympha lives in the gut of termites (helps termite digest wood) • Trypanosoma – parasite of humans in Africa

  15. PROTISTS

  16. PROTISTS • PHYLUM CILIOPHORA • Ciliates – found in fresh and salt water; usually free-living, most are larger than other protozoa • Pellicle, cilia, ectoplasm, endoplasm, food vacuole, contractile vacuole • Micronucleus (exchanged during conjugation) • Macronucleus (controls daily functions)

  17. PROTISTS • TRICHOCYSTS – spindle shaped alternating between bases of cilia; used as anchor and to paralyze prey • Oral groove – shallow furrow on one side of cell used to gather food • Locomotion – cilia; avoiding reaction  contact with unfavorable conditions and will move away • Reacts to contact, temperature, gravity, water currents, electric currents, acidity and other chemicals

  18. PROTISTS • Reproduction • Mitosis every 6-12 hours • Conjugation – become sticky and adhere to each other at oral groove and exchange nuclear material • Example = paramecium

  19. PROTIST

  20. PROTISTS • PHYLUM SPOROZOA • Members cannot move • Reproduce by producing spores • All endoparasites • Have apical complexes (structures that aid in penetration of host cells or tissues) • Example: Plasmodium – causes malaria; carried by vector (female Anopheles mosquito)

  21. PROTISTS

  22. PROTISTS • PLANT LIKE PROTISTS • Most perform photosynthesis • Contain chlorophyll in chloroplast and possibly other pigments • Divided into groups by pigment color • PHYLUM EUGLENOPHYTA • PHYLUM DINOFLAGELLATA • PHYLUM HETEROKONTOPHYTA • PHYLUM CHLOROPHYTA

  23. PROTIST • PHYLUM EUGLENOPHYTA • Usually free-living (not a parasite) • Pellicle – covering membrane; maintains shape • Ectoplasm, endoplasm • Cell mouth, gullet, reservoir (holds flagella), contractile vacuole, food vacuole • Stigma (eyespot) - light sensitive • Nucleus, chloroplasts

  24. PROTISTS • Movement toward light using flagella; flagella pulls cell; euglenoid movement  expansion and contractions of entire cell • Nutrition – can capture food; can absorb nutrients from water or carry on photosynthesis • Reproduction – mitosis; form cyst during harsh times • Example: euglena; volvox

  25. PROTISTS

  26. PROTISTS • PHYLUM CHLOROPHYTA - GREEN ALGAE • Contain chlorophyll b is their main type (which is very similar to land plants) • Some reproduce sexually • Examples: desmids, spirogyra • Most live in fresh water or moist soil • Many live in symbiotic relationships • Lichen – organism composed of an algae and a fungi living together as one

  27. PROTISTS

  28. PROTISTS

  29. PROTISTS

  30. PROTISTS • PHYLUM HETEROKONTOPHYTA • Red algae, brown algae, golden algae • RED ALGAE • Grow in warm salt water habitats – toward surface or deep water • Perform photosynthesis • Example: Red moss

  31. PROTISTS • BROWN ALGAE • Multicellular and live in cool salt water habitats • Includes giant kelps • Have an alternation of generations life cycle (means that part of life is spent reproducing asexually and part is spent reproducing sexually)

  32. PROTISTS • Used to make a variety of products • As a thickening agent in puddings, ice cream • Used as food for animals (processed)

  33. PROTISTS • GOLDEN ALGAE – • Some species are colorless, but the vast majority are photosynthetic. • particularly important in lakes, where they may be the primary source of food for zooplankton. • not considered truly autotrophic because nearly all become heterotrophic in the absence of adequate light, or in the presence of plentiful dissolved food. • EXAMPLES - DIATOMS

  34. PROTISTS • PHYLUM DINOFLAGELLATA (termed Pyrrophyta in your book) • Nearly all have flagella • Most grow in salt water • Most are free-living (meaning they are not parasites); some have symbiotic relationships with other organisms • When agitated undergo reaction that produces light  bioluminescent

  35. PROTISTS • DINOFLAGELLATE

  36. PROTISTS • Cause the red tide • Several microscopic marine algae are notoriously poisonous to hapless humans who consume them in shellfish. • some species are poisonous to animals which feed upon them directly or indirectly. Some of the toxins these species produce are seriously toxic. Often, the algae themselves are unaffected, as are the filter feeders, especially shellfish, for whom micro-algae are the principal diet. However, to carnivores further up the food chain, including humans, these toxins are potentially FATAL.

  37. PROTISTS

  38. PROTISTS • FUNGUS-LIKE PROTISTS (MOLDS) • CHARACTERISTICS • MOST ARE SMALL AND LIVE IN DAMP PLACES • PROTISTS THAT ACT AS DECOMPOSERS ARE CALLED MOLDS • DIVIDED INTO 3 GROUPS • PLASMODIAL SLIME MOLDS • CELLULAR SLIME MOLDS • WATER MOLDS

  39. PROTISTS • PLASMODIAL SLIME MOLDS • Can weigh as much as 50 grams and be as large as a human hand (one cell!) • Single cell with many nuclei • In unfavorable conditions • Moves somewhere else • Creates a fruiting body

  40. Myxomycota - plasmodium

  41. PROTISTS • CELLULAR SLIME MOLDS • ALTERNATES BETWEEN A SPORE PRODUCING FRUITING BODY FORM AND AN AMEBALIKE FEEDING FORM • SINGLE CELLS UNITE TO FORM ONE LARGE MASS (PSEUDOPLASMODIUM) WHEN TIMES ARE HARSH

  42. The phyla of slime molds:

  43. PROTISTS • WATER MOLDS • DECOMPOSERS IN FRESHWATER ECOSYSTEMS • SOME ARE PARASITIC

  44. PROTISTS • IMPORTANCE OF PROTISTS • ECOLOGICAL ROLES • Provide an essential food base in aquatic food chains • Carry out more than 30-40% of Earth’s photosynthesis • Protozoans help keep the number of bacteria in check

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