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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Advent of The Eukaryotes Chapter 14 Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Outline Endosymbiosis Evolution of Sex General Biology of Protists Protist Reproduction Classifying Protists - Five General Categories
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endosymbiosis Most biologists believe mitochondria originated as symbiotic, aerobic eubacteria (endosymbiosis). Bacteria thought to have been engulfed by ancestral eukaryotic cells early in the history of eukaryotes.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endosymbiosis Mitochondria Bound by two membranes (Outer smooth, inner- folded) and divide by simple fusion. - Each still has own circle of closed DNA containing genes encoding for essential proteins of oxidative metabolism. Chloroplasts Bacteria-like organelles apparently derived from symbiotic photosynthetic bacteria.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endosymbiosis
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Evolution of Sex During sexual reproduction, two different parents contribute gametes to form offspring. Asexual Reproduction forms offspring identical to the parents. Parthenogenesis - Development of an adult from an unfertilized egg. - Common among insects. Self-Fertilization - One individual provides both gametes.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Evolution of Sex Sexual Reproduction provides a powerful means of shuffling genes, and rapidly generating genetic diversity. Sexual Life Cycles Zygotic Meiosis - Zygote formed by fusion of gametes is the only diploid cell. Gametic Meiosis - Gametes are the only haploid cells. Sporic Meiosis - Alteration of generations
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies General Biology of Protists Protists are eukaryotes united on the basis that they are not fungi, plants, or animals. All have cell walls. Movement accomplished by various means. - Flagella - Lobopodia - Filopodia - Axopodia
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies General Biology of Protists Cysts - Dormant form with resistant outer covering. Nutrition Phototrops (photosynthesis) Phagotrophs (ingest visible food particles) - Holozoic feeders Osmotrophs (ingest food in soluble form) - Saprozoic feeders Food Vacuoles (phagosomes)
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Protist Reproduction Multicellularity - Composed of many permanently associated cells with integrated activities. Allows for specialization. Occurs only in eukaryotes - Colonies - Permanent association, but no integration of cell activities. - Aggregates - Transient collection of cells.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Protist Reproduction Multicellular Organisms - Individuals composed of many cells that interact and coordinate their activities.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Classifying Protists Most diverse of four kingdoms in the domain. Artificial group formed for convenience. - Five general groups according to major shared characteristics. Presence or absence of cilia / flagella Presence and kind of pigment Type of mitosis Kinds of cristae in mitochondria
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Classifying Protists Molecular genetics of ribosomal s subunit. Kinds of inclusions Overall body form Outer shell or armor Modes of nutrition and movement
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs Lacking Permanent Locomotor Apparatus Largest of the five groups. Amoebas - Lack flagella and cell walls, and move with pseudopodia. Forams - Possess rigid shells and move by cytoplasmic streaming (podias). - Marine with pore-studded shells (tests). Radiolarians - Phylum Actinopoda - Glassy skeletons with many needlelike pseudopods.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Flagella Zoomastigotes Ancestor of all animals appears to have been a member of this group. - All have at least one flagellum. Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Flagella Ciliates Possess large number of cilia, fixed cell shape, and two nuclei per cell. Reproduction usually by fission. Move by beating cilia.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Nonmotile Spore-Formers Sporozoans are nonmotile, spore-forming, unicellular parasites. Responsible for many diseases. - Sporozoans of genus Plasmodium are spread among humans by mosquitoes of genus Anopheles. Malaria
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Sporozoan Life Cycle
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Dinoflagellates Photosynthetic unicellular protists, most with two flagella of unequal lengths. - One flagella beats in a groove circling body, while the other beats in a groove perpendicular to it. Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Euglenoids Freshwater protists with two flagella. - One-third are photosynthetic, while others are heterotrophic. Reproduction by mitotic cell division. Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Diatoms Photosynthetic unicellular protists with unique double shell of silica. Golden Algae Named for yellow and brown accessory pigments in chloroplasts. Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Green Algae Ancestor of true plants is a member of this group. - Contain chlorophyll a and b. - Most are microscopic and unicellular. Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Red Algae Contain red pigments (phycobilins). - Almost all multicellular and live at sea. Brown Algae Life cycle employs alteration of generations. (Kelp) Copyright © McGraw-Hill Companies Permission required for reproduction or display
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Restricted Mobility Cellular Slime Molds More closely related to ameobas.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Restricted Mobility Plasmodial Slime Molds Stream along as a non-walled multinucleate mass of cytoplasm (plasmodium). - Extend pseudopodia as they move. Water Molds Downy mildews often seen in moist environments. - All either parasitize living organisms or feed on dead organic material.
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Review Endosymbiosis Evolution of Sex General Biology of Protists Protist Reproduction Classifying Protists - Five General Categories
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Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display
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