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Learning Objectives

Kingdom Protista. Learning Objectives. Explain the endosymbiotic theory and evidence supporting it Describe identifying characteristics of the kingdom Protista Classify the different phyla of protists Compare and contrast the structure and function of different protists.

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Learning Objectives

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  1. Kingdom Protista Learning Objectives • Explain the endosymbiotic theory and evidence supporting it • Describe identifying characteristics of the kingdom Protista • Classify the different phyla of protists • Compare and contrast the structure and function of different protists

  2. Origin of Eukaryotes – Formation of Nucleus Endomembrane infolding • Infolding of membrane system forming nucleus and ER • More surface area for material exchange with envi.

  3. Eukaryotic Evolution -Endosymbiosis Hypothesis • What’s the story? • A prokaryote ingested some aerobic bacteria. The aerobes were protected and produced energy for the prokaryote. Over time the aerobes became mitochondria, no longer able to live on their own. • Some prokaryotes also ingested cyanobacteria, which can photosynthesize. Cyanobacteria became chloroplasts, unable to live on their own Plant cell Animal Cell

  4. Scientific Evidence for Endosymbiosis theory Membranes of chloroplasts and mitochondria are similar to those of living prokaryotes Mitochondria and chloroplasts have their own ribosomes that more similar to prokaryotic ribosomes than ribosomes found in eukaryotes These organelles reproduces by binary fission within the cell Mitochondria and chloroplasts have their own DNA that match living prokaryotes’ DNA. Chloroplast genes match genes of cycnobacteria (prokaryotes) • Endosymbiosis doesn’t explain how multicellarity came about

  5. Protists - General Characteristics Most are single-celled, some multi-cellular (algae) All are eukaryotic Can be heterotrophic or autotrophic Some have cell walls Some are motile Most live in water, some live in moist soil or even the human body

  6. Classification and Phylogeny

  7. 3 main groups of Protists Characterized by how they move and get their nutrients.

  8. Protozoa Animal-Like Protists Means “first animals” Scavengers or predators Heterotrophs some are parasites Motile Most live as single cells but others form colonies Vary in shape and size.

  9. Protozoa Phyla Animal-Like Protists Protozoa are classified into four phyla based on their methods of locomotion:

  10. Animal-Like Protists 2. Sarcodines • the amoebae • No cell wall  can change shape • produce pseudopods (false feet) for movement and to engulf their prey (extensions of their cytoplasm) • Intestinal amoebas in human cause chronic diarrhea 1. Zoomastigina (Flagellates) one or more flagella (whip-like tail) rotate Some are parasites, some are mutalistic symbionts or some are free-living. Most symbionts live in digestive systems and help the host animals break down cellulose (win-win situation b/t flagellates and termite)

  11. Animal-Like Protists Amoeba’s lunch: http://www.youtube.com/watch?v=pvOz4V699gk

  12. 3. Ciliates/Ciliophora Animal-Like Protists • Ex. paramecium • Have cilia, tiny hair-like projections that beat together in rhythm for locomotion • Can also move food into the gullet, which leads to a food vacuole. • Balantidium coli –in human intestine Diarrhea

  13. 4. Sporozoans Animal-Like Protists Producespores Passive movement (none) parasites Plasmodium vivax causes one type of malaria in humans.

  14. Life Cycle of Malaria-causing Plasmodium Watch: http://highered.mcgraw-hill.com/olc/dl/120090/bio44.swf

  15. Plant-Like Protists Algae

  16. Algae Plant-Like Protists • Algae - not a proper taxonomic group – there are algae in plantae & bacteria kingdom. • Classified into six different Protist “algae” phyla. Simple, aquatic, plant-like organisms that contain chlorophyll Lack the leaves, roots, stems and water-conducting tissues of plants Range in size (single cells to giant seaweeds 60 m in length)

  17. 6 Algae Phyla Multicellular Plant-like Protists Unicellular Plant-like Protists Major producers in food web

  18. Protists in global carbon cycle Take away message from this graph? algal bed and reefs contribute the largest % of net primary production on Earth, combining productivity in both ocean and aquatic envi. Protists play a vial role in C cycling __________________________________________________________________________________________________________________________________________ _______________________________________________________________________

  19. Multicellular, Plant-Like Protists 2. Brown Algae (Phaeophytes): - in cold water. - cell walls made of cellulose - commonly called seaweeds (ex. kelp) . - Have holdfasts to anchor body on rocky surfaces • 3. Red Algae (Rhodophytes): • found in warm seawater. • Red because its pigments absorb green, violet and blue light which penetrate the furthest in water, allowing red algae to live at great depths. • SUSHI! & Agar for bacterial growth 1. Green algae (Chlorophytes) In freshwater, even sloth’s fur cell walls contain cellulose Ex. Spirogyra (picture)

  20. Rhodophytes (red algae)

  21. Unicellular, Plant-Like Protists 5. Dinoflagellates (Pyrophytes) • Photosynthetic; mostly marine • stiff cellulose protective coats • Have two distinct flagellae in life cycle • Numerous; important base for marine food chains • Contain toxins (build up in shellfish that eat them). • Phosphorescent (photosynthetic pigment):form “red tides” • 6. Euglenoids (Euglenophytes) • Freshwater; have chloroplasts • One large anterior whip-like flagella (updated) • Eat smaller organisms if no sun; Eyespot to find sunlight • Reproduce via mitosis 4. Diatoms (Chrysophytes) most abundant algae in the oceans rigid cell walls contain silica (sand & glass) big component of plankton major source of atmospheric oxygen Main producers of aquatic food webs

  22. Slime and Water Moulds Fungi-Like Protists Have the characteristics of fungi, protozoa and plants. Glide from place to place and ingest food like protozoa. Cellulose in their cell walls like plants. Also absorb nutrients from their environment like fungi (nutrients from the dead)

  23. 1. Water Moulds (Phylum Oomycota) Fungi-Like Protists Ex. Water moulds, white rusts and downy mildews. Filamentous, resemble fungi Most live as saprotrophs on dead organic materials, but some are parasitic on plants, insects and fish. Extend fungus like threads into their host where they release digestive enzymes and absorb the nutrients. The cause of the Irish Potato Famine.

  24. 2. Plasmodial Slime Moulds (Phylum Myxomycota) Fungi-Like Protists Dog vomit slime mould  visible to the naked eye as tiny slug like organisms that creep over damp, decaying plant material in forests and fields. This blob, called a plasmodium, contains many nuclei. Feed in a similar manner to amoebae. Spores form in improper living conditions.

  25. 3. Cellular Slime Moulds (Acrasiomycota) Fungi-Like Protists exist as individual amoeboid like cells with one nucleus each. Feed by ingesting tiny bacteria or yeast cells. When food becomes scarce, the cells release a chemical that causes them to gather together to form a pseudoplasmodium. This is a jelly-like mass, which produces a sporangia that releases spores.

  26. Protists’ modes of reproduction Asexual Sexual Paramecia Results: 2 genetically identical paramecia daughter cells Results of conjugation: Two cells exchanged their genetic materials Via binary fission Involves conjugation Alternation of generation (multicellular protists)

  27. Multicellular Protists’ Reproduction Sexual reproduction involves formation of gametes Gametes are haploid (half the usual # of chromosomes) When a sperm meets an egg, a zygote is formed having full set of chromosomes Zygotes are thus diploid (full set of chromosomes) Multicellular protists can alternate between a diploid and a haploid stage called Alternation of generations Both diploid and haploid stages are required for the life cycle to be completed in such protists

  28. Brown algae’s alternation of generation life cycles (is Haploid, multicellular) (Diploid) Watch Alternation of generations Green algae: http://kisdwebs.katyisd.org/campuses/MRHS/teacherweb/hallk/Teacher%20Documents/AP%20Biology%20Materials/Diversity/Alternation%20of%20Generation/28_A01s.swf

  29. Large brown algae is a diploid sporophyte • Sporophyte produces single-celled, haploid spores • Spores then grow into multicellular, haploid gametophytes • Gametophytes will produce haploid sperms and eggs • When a sperm is fused with an egg, a diploid zygote is formed which later grow into a multicellular sporophyte (i.e. the large brown algae). Summarize Brown algae’s alternation of generation

  30. Recap and review (HW if not done in class): Watch: http://www.youtube.com/watch?v=-zsdYOgTbOk Q1: How is protista different from kingdom archaea and bacteria? A: Q2: How is protista different from kingdom fungi? A: Q3: How is protista different from kingdom plantae? A: Q4: How is protista different from kingdom animalia? A:

  31. Recap and review (Cont.) Watch: http://www.youtube.com/watch?v=-zsdYOgTbOk Q5: Three modes of nutrition of protists? A: Q6: Your friend one day claims that malaria can be effectively treated with antibiotics. Do you think so too? Why or why not? A: Q7: Use today’s lesson note to summarize the importance of protists (i.e. their benefits and harms to us)

  32. Recap and review (Cont.) Q8: What are some implications of climate change, particularly ocean acidification and change in global temperature, on the livelihood of the marine protists and the spread of malaria? • Q9: Research the following about African sleeping sickness: • What causes it? • How is it spread? • What are the symptoms? • How can it be treated?

  33. Belong to Phylum: Euglenoids General symptoms include: Drowsiness during the day, Fever, Headache, Insomnia, uncontrollable Sleepiness, Sweating Trypanosoma brucei & African sleeping sickness Without treatment, death can occur within 6 months from cardiac failure Complications include: Injury related to falling asleep while driving or during other activities Gradual damage to the nervous system Uncontrollable sleep as the disease gets worse Coma

  34. Irish Potato Famine (1845- 1852) • Caused by Phytophthora infestans • - A fungi-like protist (Oomycota); not a viroids

  35. Beaver fever • Caused by Giadia lambia or G. intestinalis • Class: Zoomastigophora •  single-celled protozoa (i.e. animal-like protist)

  36. Watch Alternation of generations Green algae: http://kisdwebs.katyisd.org/campuses/MRHS/teacherweb/hallk/Teacher%20Documents/AP%20Biology%20Materials/Diversity/Alternation%20of%20Generation/28_A01s.swf

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