2Protists are Divided into 3 Catagories The animal-like protistsThe plant-like protistsThe fungi-like protists
3Protists are Eukaryotic Can be unicellular or multicellular Can be motile or not (flagella and cilia)Can be photoautotrophs or chemoheterotrophs or bothContain 2 or more chromosomes with many histones and other proteins.
4Animal-like Protists Phylum Sarcodina (Locomotion is via psuedopodia) Amoebas: Naked, soft-bodied cells that live in freshwater, marine and soil.Foraminiferans (many chambered test; composed of CaCO3): primarily marineHeliozoans: Have fine needle-like psuedopodia radiating from body like sun rays. Largely fresh waterRadiolarians (test is composed of silicon dioxide) found in open, shallow waters.
10SarcodinaUse ameoboid movement made possible by cytoplasmic streaming to get around.Endoplasm (inner) pushes on ectoplasm (outer) to create the arm-like extention.Because they live in an aquatic environment they need a contractile vacuole to regulate water pressure inside the cell.
11Diseases associated with Sarcodina Ameobic dysentery: Entameoba histolyticaReproduction- Binary fission- Budding- formation of cysts during times of stress.
12Animal-like protists (cont.) Phylum CiliophoraParameciumReproduces via conjugation and binary fission.Important parts include oral groove, pellicle, mouth pore, gullet, anal pore, macronucleus and micronucleus.
13Animal-like protists: Ciliaphora cont. Reproduction:Conjugation followed by binary fissionBinary fission aloneParameciums divide along a transverse line
25Plant-like Protists Characteristics Autotrophs Lack tissue differentiationUnicellular and muticellularAquaticContain pyrenoids (organelles that synthesize and store starch.
26Plant-like Protists cont. Structure of thallus: body portion of the algae.Body structure is divided into 3 types.Unicellular E.g. phytoplanktonColonial E.g. volvoxFilamentous e.g. SpirogyraMulticellular e.g. Ulva
27Plant-like Protists cont. ClassificationThey are classified based on color, type of chlorophyll, form of food-storage and cell wall composition.ReproductionSome reproduce only via asexual reproduction while other have both asexual and sexual reproduction. See later slides for details.
28Plant-like Protists cont. Phylum: EuglenophytaEuglena (euglenoid)Photosynthetic pigmentsChlorophylls a and b, carontenoids, xanthophyll.Movement by flagella. Stigma detects light and euglena move towards it.Can be heterotrophic if deprived of light.
30Plant-like Protists cont. Phylum: Chrysophyta (the golden algae) Yellow-green algaeMost are fresh water algae but a few are found in a marine environment.golden color due to the pigment fucoxanthin (a carotenoid) which masks the chlorophyllStores much of its surplus energy as oil and are important in the formation of petroleum deposits
32Plant-like Protists cont. Bacillariophyta: the diatomsAbundant in both freshwater and marine.Have shells that are pill box-like that consist of silicon dioxide. Each half of the shell is called a valve.Some shells are centric (circular or triangular) and are marine.Others are pennate (rectangular) and are found in freshwater. Move by threads that attach to water surface.
35Plant-like Protists (cont.) Phylum Dinoflagellatadinoflagellatesred tides (Gonyaulax catanella) produces neurotoxinSome have bioluminescence (Noctiluca)All have 2 flagella, are unicellular, mostly marine and contain pigments chlorophyll, carotenoids, and other red pigments.
38Plant-like Protists (cont.) Phylum: Rhodophyta (the red algae) but may appear green, purple, or greenish-blk.MulticellularTropical waters and along rocky coasts in colder waters.Pigments: chlorohyll, phycobilins (red/blue) Good at absorbing green and blue/green light waves which can penetrate below 100 m in water.
39Rhodophyta cont.Some have cell walls coated with a sticky substance called carageenan (used in cosmetics, gelatin capsules and cheese).The cell walls contain agar which is extracted and used to make media for culturing microorganisms.
42Plant-like Protists (cont.) Phylum: Phaeophyta (the brown algae)All are multicellularLargest are kelpPigments include chlorophyll and fucoxanthinFood is stored as laminarinMacrocysitis cell walls contain alginate (used as a stabilizer in ice cream).
43Plant-like Protists (cont.) Phylum: Phaeophyta (cont.)Parts of kelpBody is called thallus“Roots” are called holdfasts“Stems” are called stipe.“Leaves” are called blades.Air bladders keep thallus afloat allowing access to lightSargassum serve as floating ecosystemContains a commercially important substance called alginate. Alginate is used as a stabilizer in most ice creams.
45Plant-like Protists(cont.) Phylum: Chlorophyta (the green algae)It is believed that this group gave rise to land plants.Most diverse (7000 identified species)Can be unicellular or multicellular, colonial or sheets.Found in fresh water and marine environmentsPigment mostly chorophyllStore food as starch.Many reproductive methodsSee Ulva for life cycleOften have symbiotic relationships with fungi (lichens).
47Chytrids (Phylum Chtidiomycota) Are believed to be the evolutionary link between protists and fungi (Share enzymes and biochemical pathways).Live in fresh water and marineSome are saprobic decomposers while others are parasites.Single-celled species produce flagellated asexual spores (1 reason it is in Protista).Chitin reinforces cell wall.Cell walls are sieve like between cells allowing flow of cytoplasm throughout mycelium.
48Water molds (Phylum Oomycota) Distantly related to red algaeReproductionProduce flagellated asexual zoospores which germinate into long thread-like cells forming a thallus.Sexual reproduction occurs when a connecting tube is formed between oogonia and antheridia. Zygote (2n) develops into new thallus.Key decomposers of aquatic habitatsSome parasitizePhytophtlora infestans caused “late blight” and the great Irish potato famine.Blight is a disease of plants characterized by decay and discoloring of leaves.
49Fungi-like protists cont. Slime molds contain 2 phylumAcrasiomycota: Cellular slime moldsLive as haploid cells that move like amoebas.Asexually reproduce. Sexual reproduction rare or absent.When food/water is scarce a chemical is released causing them to gather into a pseudoplasmodium.Pseudoplasmodium produces fruiting body which produces haploid spores.
51Fungi-like protists cont Mxyomycota: plasmodial (acellular) slime moldAcellular because the plamodium (group of feeding cells) lack cell walls & appear as a mass of cytoplasm with thousands of nuclei.Each nuclei is diploid.Mass phagocytizes decaying leaves/debris.When food/water is scarce the plasmodium crawls to an exposed area and forms a stalked fruiting body which undergoes meiosis to produce haploid spores. These spores will give rise to haploid reproductive cells which fuse to form a diploid nucleus.Mitosis occurs but cytokinesis never does.