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EUKARYA KINGDOM PROTISTA I
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Origin of Eukaryote: The Endosymbiotic Theory (1960) Pages 229, 307
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Prove: Endosymbiotic Plastid and mitochondria have their own DNA & ribosome that are 70s not 80s They divide in a way similar to Prokaryotes, lack microtubules Their DNA is circular, naked Their ribosome are sensitive to the same antibiotics that interfere with prokaryotes ribosome Evidence of symbiotic relationship between bacteria & protists, marine invertebrates, algae & protozoan (Fig. 12-11) Mitochondria arose first (common to all Eukaryotes), from purple nonsulfur bacteria!
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Meiosis & Life cycles For meiosis see page 236 In eukaryote a diploid stage undergo meiosis to produce a haploid stage These two stages alternate in three patterns Gametic meiosis: most animals & some protists ** Sporic meiosis (alternation of generations: plants & many algae** Zygotic meiosis: Fungi & some algae**
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Gametic Meiosis Fertilization Gametes - + Meiosis (spermatogenesis) Diploid individual Zygote This cell undergo meiosis - gamete + Gamete e.g. Human & some protists
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Sporic Meiosis Meiosis Fertilization spores - + Sporophyte (Diploid individual) Zygote - Gamete + Gamete Gametophyte (Haploid individuls) This cell undergo meiosis e.g. Plants
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Reproductive Cycles Animals and Plants Adult ♀ Adult ♂ Egg Zygote Embryo 2n 1n Meiosis Fertilization Sperm Spore Gametophyte Sporophyte
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Zygotic Meiosis Meiosis Fertilization Haploid cells - + Zygote - Gamete + Gamete Haploid individuals e.g. Fungi
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Classification of the Protists Protista is established to hold problematic species Each algal group must have its own evolutionary line Organisms of uncertain origin are paced in the Protista Protista includes: Plant-like organisms but gametes & zygotes not protected Fungi-like organisms but have flagella & lack chitin in cell wall Animal-like organisms but no embryonic development
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Ecology of Aquatic Algae Marine algae & cyanobacteria form phytoplankton Importance Important in carbon cycle (absorb ½ CO 2 produced by human activities) Transform CO 2 into (CH 2 O) n & CaCO 3 Cause algal blooms (red & brown tides) Increase sulfur oxides in our atmosphere
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Lake Neatahwanta, Fulton, NY
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Euglenoids: Phylum Euglenophyta e.g. Euglena** Like green algae, have chl(a), (b) & carotenoids suggesting a symbiotic relationship Only 1/3 of the phylum has chloroplast, the rest are heterotrophic Euglenoids occur in freshwater rich in organic matter
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Euglena Reproduce by mitosis & lengthwise
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Plasmodial Slime Molds: Phylum Myxomycota The name mold “thought to have a relation with fungi” Seems to have no close relation to other organisms Plasmodium: amoeboid body with no cell wall** Phagocyte: heterotrophic
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Sclerotium Plasmogamy
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Oomycetes: Phylum Oomycota They are not Fungi because Cell wall has cellulose-like polymers Chromosomes not highly condensed as in fungi spores are flagellated They are saprobic, few are parasitic Pathogens of Coca, pineapple, tomatoes, rubber, papayas, onions, citrus e.g. the genus Plasmopara** e.g. Phytophthora infestans (Late blight of potato)**
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Downy mildew in Grapes: Plasmopara viticola Downy mildew in grapes, threaten the entire wine production in France (introduces from the States 1870) http://www.inra.fr/Internet/Produits/HYP3/pathogene/3plavit.htm#det
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Late Blight of Potato (Phytophthora infestans) Responsible for the great famine of 1846-47 in Ireland
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Dinoflagellates: Phylum Dinophyta Mostly unicellular & biflagellate** Have chl. a, c, & carotenoid Important part of marine phytoplankton Many produce toxins (red & brown tides)
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Dinoflagellates Unique: flagella move within 2 groves Ceratium http://www.microscopy-uk.org.uk/mag/artsep01/dinof2.html
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Red tide in Texas Bay, Gymnodinium breve Red tide in Texas Bay, Gymnodinium breve
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Diatoms: Phylum Bacillariophyta Very important component of phytoplankton Occur in huge # 30-50 m/1 cm of a submerged rock (1/4 of total carbon fixed) They lack flagella & have unique shells * Pennate diatoms: bilaterally symmetrical** * Centric diatoms: radially symmetrical** - Centric float better therefore more abundant
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Pennate Diatoms
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Diatoms: often compared to a shoe box and its lid (frustules) Cell wall has an outer layer of silica (glass) 3 µm Lower valve (the box) Upper valve (lid)
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Chrysophytes: Phylum Chrysophyta Have chl(a) & (c) masked with a golden-brown fucoxanthin (=chrysophyte)** Mostly unicellular or colonial; flagellated Found in fresh & salt water all over world Reproduction is asexually by zoospores
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Synura sp. http://www.spea.indiana.edu/e455-jones/synura.jpg
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