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Published byGregory Boone Modified over 9 years ago
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Domain Bacteria Domain Archaea Domain Eukarya Common ancestor Kingdom: Protists Domain Eukarya
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General characteristics Classification criteria eukaryotes not animal, plant or fungi That’s more of what they’re not & not what they are!
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Great Diversity dinoflagellates & ciliates euglenoids brown algae & diatoms red algae green algae miscellaneous?
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Problems with Protist Classification Euglenozoa Animals Streptophyta (includes land plants ) Choanoflagellida Fungi Chlorophyta Rhodophyta Stramenopila Alveolata Archaea Bacteria Something’s not right here!
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How did Eukaryotes Evolve?
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Theory of Endosymbiosis Ancestral eukaryotic cell Eukaryotic cell with mitochondrion internal membrane system aerobic bacterium mitochondrion chloroplast Eukaryotic cell with chloroplasts photosynthetic bacterium Paramecium & symbiont Chlorella
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Protist Diversity The full spectrum of modes of life from unicellular to multicellular autotrophic to heterotrophic asexual to sexual reproduction pathogenic to beneficial sessile to mobile
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Mobility How Protists move flagellum cilia pseudopod
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Protist Diversity Animal-like Protists heterotrophs, predators Amoeba Paramecium Stentor Paramecium with food vacuoles stained red Amoeba ingesting a Paramecium
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Protist Diversity Plant-like Protists autotrophs, photosynthesis Euglena algae diatoms
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Protist Diversity Parasitic & pathogenic Protists malaria Giardia trypanosomes Plasmodium Giardia Trypanosoma
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Protist Diversity Beneficial & necessary Protists small algae + diatoms much of the world’s photosynthesis produces ~90% of atmospheric oxygen heterotrophic protists key ecological role at base of marine food web
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Kingdom: Euglenozoa Have flagella Phyla: Euglenoids – may be autotrophic or heterotrophic Kinetoplastids – symbiotic and may be parasitic, e.g. causes African Sleeping Sickness (bite of tsetse fly)
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Kingdom Alveolata Photosynthetic flagellates, parisitic group and ciliates combine to form this kingdom. Dinoflagellates – phytoplankton, cause red tides, some are coral symbionts that produce for reef community
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Apicomplexans – all are parasitic, example plasmodium. Ciliates – All have cilia to move and feed. 2 types of nuclei (Stentor, paramecium) Macronucleus – have several ;everyday functions, asexual reproduction Micronucleus – 1 for sexual reproduction
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Stramenopila Includes photosynthetic and heterotrophic organisms All possess hairlike projections on flagella Chloroplasts derived from secondary endosymbiosis Diatoms (Bacillariophyta) – glass-like cell walls Freshwater and marine plankton Diatomaceous earth used for filtering and abrasive purposes
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Golden Algae (Chrysophyta) – carotene and xanthophyll accessory pigments Freshwater and marine plankton Oomycota – Oomycota – White rust Mildew Water mold – on dead fish All are fungus-like Caused Irish potato famine, by destroying crops
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Phaeophyta – Brown algae Phaeophyta – All are multicellular Includes seaweeds Seaweed adaptations: Analogous plant-like structures Body = thallus Root-like structure – holdfast Stem-like structure – stipe Leaf-like structure - blades
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Cercozoa and Radiolaria Have threadlike pseudopodia Actinopods – heliozoans and radiolariansradiolarians Foraminiferans – mostly marine Porous shells Mostly fossils White cliffs of Dover due to fossilized foraminiferans
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Amoebozoa Identify them by lobe shaped pseudopods Phylum: Gymnamoebas – amoebasamoebas Mitosis with persisting nuclear envelope Asexual reproduction Entamoebas - parasitic, cause amoebic dysentery.
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Plasmodial Slime Molds – show cytoplasmic streaming Multinucleated plasmodium in feeding stage Cellular slime mold are haploid
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Kingdom: Rhodophyta No flagellated stage, evidence shows they lost flagella during evolution Accessory pigment phycobillins Color depends on depth Found in deepest waters Has carageenin – used in agar and agarose
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Chlorophyta Cellulose cell walls Chl a is primary pigment Starch as polysaccharide storage molecule Hmmm… What does that sound like
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Examples of Green Algae Chlamydomonas reproduce both sexually and asexually Spirogyra – filamentous green algae, show both sexual and asexual reproduction Volvox - colonial green algae
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Traditional view of three domains
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DNA analysis dictates that this is a more likely scenario
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Multicellularity Evolutionary novelty that broke into new adaptive zones occupied by larger organisms Possibly derived from colonial aggregates Cell specialization led to multicellularity Led to plant, fungi and animal kingdoms
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Any Questions??
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Stramenopila Includes photosynthetic and heterotrophic organisms All possess hairlike projections on flagella Chloroplasts derived from secondary endosymbiosis, possibly red algae Diatoms (Bacillariophyta) – glass-like cell walls Diatoms Freshwater and marine plankton Diatomaceous earth used for filtering and abrasive purposes
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