protists
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PROTISTS
PROTISTS
COMMON EXAMPLES:Amoeba, paramecium, euglena, volvox, plasmodium
EUKARYOTICHave a nuclear membrane
VERY DIVERSE GROUPmost are unicellular, microscopic, aerobicSome are autotrophic, heterotrophic, sexual, asexual
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ENDOSYMBIONT THEORYEarly eukaryotes developed symbiotic relationships with prokaryotic cells
Prokaryotic cells lived inside eukaryotic cells
Over time, the smaller prokaryotic cells evolved with the eukaryotic cells to become mitochondria and chloroplasts
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EXCRETION AND OSMOREGULATION
Water balance = osmoregulation
Done by contractile vacuole
Wastes removed by diffusion
RESPIRATIONCarbon dioxide and oxygen diffuse in and out
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REPRODUCTIONAsexual
Mitosis and cytokinesis
Budding – similar to mitosis except daughter cell is smaller than parent
Schizogony – nucleus divides many times and cytoplasm divides to form many daughter cells as there are nuclei
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SEXUALLYMeiosis – special nuclear division to reduce chromosome number to haploid
Union of gametes = diploid zygote
Syngamy – fertilization between two individuals
Autogamy – two gametes fuse within one organism
Parthenogenesis – development of organism from gamete without fertilization
Conjugation – exchange of nuclear material between two individuals
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DOMAIN EUKARYOTA
KINGDOM PROTISTA
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ANIMAL LIKE PROTISTS = PROTOZOA
Classified by method of movement
PLANT LIKE PROTISTS = ALGAE
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PROTIST CLASSFICATIONSeparated by feeding habits (nutrition)
AutotrophicAble to make own food
Photosynthetic – 30-40% of all photosynthesis worldwide is done by algae
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PROTOZOAHeterotrophic
Unicellular
4 groups
Sarcodinians
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PHYLUM SARCODINAAquatic, clear cytoplasm, irregular shape
Move by extending lobes of their cytoplasm
Pseudopods (false feet)
Plasmolemma – elastic cell membrane
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LABEL THIS AMEOBA
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PHYLUM ZOOMASTIGINAOften called flagellates because they move using flagella
Absorb food by diffusion through cell membrane
Live off of dead or decaying organic matter or some are parasites
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PHYLUM CILIOPHORACiliates – found in fresh and salt water; usually free-living, most are larger than other protozoaPellicle, cilia, ectoplasm, endoplasm, food vacuole, contractile vacuoleMicronucleus (exchanged during conjugation)Macronucleus (controls daily functions)
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TRICHOCYSTS – spindle shaped alternating between bases of cilia; used as anchor and to paralyze preyOral groove – shallow furrow on one side of cell used to gather foodLocomotion – cilia; avoiding reaction contact with unfavorable conditions and will move away
Reacts to contact, temperature, gravity, water currents, electric currents, acidity and other chemicals
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ReproductionMitosis every 6-12 hours
Conjugation – become sticky and adhere to each other at oral groove and exchange nuclear material
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PHYLUM SPOROZOAMembers cannot move
Reproduce by producing spores
All endoparasites
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PLANT LIKE PROTISTSMost perform photosynthesis
Contain chlorophyll in chloroplast and possibly other pigments
Divided into groups by pigment color
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PHYLUM EUGLENOPHYTAUsually free-living (not a parasite)
Pellicle – covering membrane; maintains shape
Ectoplasm, endoplasm
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Movement toward light using flagella; flagella pulls cell; euglenoid movement expansion and contractions of entire cell
Nutrition – can capture food; can absorb nutrients from water or carry on photosynthesis
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PHYLUM CHLOROPHYTA - GREEN ALGAE
Contain chlorophyll b is their main type (which is very similar to land plants)
Some reproduce sexually
Examples: desmids, spirogyra
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PHYLUM HETEROKONTOPHYTARed algae, brown algae, golden algae
RED ALGAEGrow in warm salt water habitats – toward surface or deep water
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BROWN ALGAEMulticellular and live in cool salt water habitats
Includes giant kelps
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Used to make a variety of products
As a thickening agent in puddings, ice cream
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GOLDEN ALGAE –Some species are colorless, but the vast majority are photosynthetic.
particularly important in lakes, where they may be the primary source of food for zooplankton.
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PHYLUM DINOFLAGELLATA (termed Pyrrophyta in your book)
Nearly all have flagella
Most grow in salt water
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DINOFLAGELLATE
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Cause the red tide
Several microscopic marine algae are notoriously poisonous to hapless humans who consume them in shellfish.
some species are poisonous to animals which feed upon them directly or indirectly.
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FUNGUS-LIKE PROTISTS (MOLDS)CHARACTERISTICS
MOST ARE SMALL AND LIVE IN DAMP PLACES
PROTISTS THAT ACT AS DECOMPOSERS ARE CALLED MOLDS
DIVIDED INTO 3 GROUPS
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PLASMODIAL SLIME MOLDSCan weigh as much as 50 grams and be as large as a human hand (one cell!)
Single cell with many nuclei
Myxomycota - plasmodium
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CELLULAR SLIME MOLDSALTERNATES BETWEEN A SPORE PRODUCING FRUITING BODY FORM AND AN AMEBALIKE FEEDING FORM
The phyla of slime molds:
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WATER MOLDSDECOMPOSERS IN FRESHWATER ECOSYSTEMS
SOME ARE
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IMPORTANCE OF PROTISTSECOLOGICAL ROLES
Provide an essential food base in aquatic food chains
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