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Kingdom Protista (2) Biology 11 Mr. McCallum
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REVIEW TIME
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Animal-like Protists (Protozoa) Heterotrophs Must consume to gain nutrition Holozoic Engulf their food Saprozoic Absorb pre-digested or soluble nutrients through membrane 4 phyla Sarcodina Mastigiphora Ciliophora Sporozoa
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Animal-like Protists (2) Larger population numbers, and larger number of species overall than bacteria Occupy a diverse range of moist habitats Huge range/variability in size (micrometers to centimeters) Small red blood cell can contain a dozen Usually undergo asexual reproduction Binary fission Can form cysts (hard protective covering over cell membrane – resting/dormant cells)
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Classification Distinguished by their modes of locomotion Cilia, flagella, pseudopodia, etc. Also: Types of organelles Life cycle Mode of reproduction Free-living or parasitic
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1. Phylum Sarcodina Free-living Few parasitic species in animal intestines Thrive in fresh water, salt water, and soil Use pseudopods (“false feet” – finger-like projections) Provide motility through extension and retraction Allow organism to feed by engulfing food particles E.g.: Amoebas, foraminiferans, radiolarians, heliozoans
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E.g.: Amoeba Largest and least complex protozoan Two layers of cytoplasm Ectoplasm : thin, semi-rigid layer under plasma membrane Endoplasm : more fluid, fills the inside of the cell Named chaos chaos by Linnaeus Continuous movement of endoplasm causing amoeba to constantly change shape
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E.g.: Amoeba (2) Feeds by phagocytosis Pseudopods flow around and engulf food particles Food then enclosed in food vacuole Contractile vacuole collects excess water – discharges it through pore in plasma membrane Asexual reproduction Binary fission Typically 1 division a day
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2. Phylum Mastigophora Motile Move through use of flagella (one or more!) Free-living forms found in both fresh and salt water Majority are parasitic Live within other organisms Causing disease in animals Asexual reproduction Longitudinal fission Flagellates also form cysts Way in which many parasitic forms are spread from host to host E.g.: Giardia lamblia
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Giardia lamblia = Beiber fever NOT QUITE…. BEAVER FEVER
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E.g.: Giardia lamblia (Beaver Fever) Parasite that causes stomach upset and diarrhoea Can have more severe effects in some individuals Cattle and wild animals often have the parasite Infection occurs when we drink or eat food tainted with the feces of these infected animals BOIL WATER if consuming directly from a stream
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3. Phylum Ciliophora Most complex and advanced of the protozoans Characterized by cilia Hair-like projections Shorter and more abundant than flagella Can cover the entire organism Motile organisms have cilia synchronized for swimming Non-motile (sessile) organisms use cilia for attachment Can undergo asexual (binary fission) or sexual reproduction (conjugation) Live in both freshwater and marine habitats E.g.: Paramecium
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REVIEW TIME
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E.g.: Paramecium Most commonly studied ciliate Oral groove contains mouth Connects to gullet Cilia in gullet sweep bacteria and food particles into the cavity Digestion takes place in food vacuole Waste expelled through anal pore Excess water collected in contractile vacuole
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E.g.: Paramecium (2) Two nuclei Large macronucleus – controls majority of cell activities Smaller micronucleus – involved with reproduction Reproduction often asexual (binary fission), can undergo sexual (conjugation) After conjugation, daughter cells undergo binary fission Defence mechanism Hundreds of poison-laden barbs ( trichocysts ) can be discharged to drive away predators and capture prey
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4. Phylum Sporozoa Lack means of independent locomotion Some have flagella while maturing Display complex life cycles Exclusively parasitic Depend exclusively on body fluids of host for movement Simple structure with fewer organelles and specialized structures Characterized by a spore-like stage Reproductive cells that can produce a new organism without fertilization (sporozoites) In cases where two hosts are involved – reproduction is sexual in one host, asexual in the other host Insects are frequently vectors – responsible for transmission
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E.g.: Plasmodium Notorious P.R.O.T.I.S.T. Responsible for causing malaria in humans, other mammals, and birds Malaria is a disease caused by the plasmodium parasite (phylum Sporozoa) Transmitted by the female anopheles mosquito Nearly half a billion people get Malaria each year – nearly one million die of the disease Sub-Saharan Africa suffers 90% of all Malaria deaths
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3 reasons why we still haven’t gotten rid of malaria List the three reasons Sonia Shah believes are responsible for the prevalence of malaria in modern day society… Be PREPARED to discuss these, along with any other questions/facts relating to malaria!
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Fungi-like Protists Heterotrophs, decomposers, and external digesters Exhibit complex life cycles and exist in various cellular forms
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1. Gymnomycota (Slime Moulds) Prefer cool, shady, moist places Often under rotting logs, fallen leaves Leave slimy trail as they move along the ground At some point in life cycle resemble protozoans (amoeba-like, have flagella, etc.) At other points, they produce spores Do not always remain as single celled organisms Becoming multicellular is a TREMENDOUS advancement! Lays groundwork for cell specialization
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2. Oomycota (Water Moulds) Found notably in fresh water environments As well as upper surface of moist soil E.g.: Downey mildews and white rusts Produce filamentous hyphae Decomposers
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Create a table to COMPARE/CONTRAST the three groups of PROTISTS that we have examined as a class (plant-like, animal-like, and fungi-like). Be sure to include EXAMPLES OF ORGANISMS that we have discussed, as well as the MAIN SIMILARITIES and the MAIN DIFFERENCES between and within these groupings.
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