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Explore the world of protists, a diverse group of eukaryotic organisms that includes common examples like amoeba, paramecium, and euglena. Learn about their classification, including animal-like protists (protozoa), plant-like protists (algae), and fungus-like protists (molds). Discover the ecological roles of protists, such as providing a food base in aquatic food chains and contributing to Earth's photosynthesis.
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PROTISTS • COMMON EXAMPLES: • Amoeba, paramecium, euglena, volvox, plasmodium • EUKARYOTIC • Have a nuclear membrane • VERY DIVERSE GROUP • most are unicellular, microscopic, aerobic • Some are autotrophic, heterotrophic, sexual, asexual
PROTISTS • DOMAIN EUKARYOTA • KINGDOM PROTISTA • Any eukaryote that is not classified as a fungus, plant, or animal is a PROTIST
PROTISTS • ANIMAL-LIKE PROTISTS = PROTOZOA • Classified by method of movement • PLANT-LIKE PROTISTS = ALGAE • Classified by pigment color • FUNGUS-LIKE PROTISTS = MOLDS • Classified by body form
PROTISTS • PROTOZOA • Heterotrophic • Unicellular • 4 groups
PROTISTS • SARCODINA • Aquatic • Move by extending lobes of their cytoplasm called pseudopods (false feet) • Example: Amoeba proteus
PROTISTS • CILIOPHORA • Cilia for locomotion • Larger than other protists • Example: Paramecium
PROTISTS • SPOROZOA • Members cannot move • All are endoparasites • Example: Plasmodium – causes malaria
PROTISTS • PLANT-LIKE PROTISTS • Most perform photosynthesis • Contain chlorophyll in chloroplast and usually other pigments • Divided into groups by pigment color • Euglenophyta • Green algae • Red/brown/gold algae • Dinoflagellages (clear)
PROTIST • EUGLENOPHYTA • Stigma (eyespot) - light sensitive • Movement toward light using flagella; flagella pulls cell • Example: Euglena; Volvox
PROTISTS • GREEN ALGAE • Contain chlorophyll b is their main type (which is very similar to land plants) • Many live in symbiotic relationships • Lichen – organism composed of an algae and a fungi living together as one • Example: Spirogyra
PROTISTS • Red/brown/gold algae • Brown algae used as a thickening agent in toothpaste, pudding, ice cream; ex. Giant kelp
PROTISTS • Gold algae is especially important in lakes, not true autotrophs because nearly all become heterotrophic in the absence of adequate light; ex. Diatoms
PROTISTS • Dinoflagellates • When agitated, undergo reaction that produces light bioluminescent • Cause red tide
PROTISTS • FUNGUS-LIKE PROTISTS (MOLDS) • Called “molds” because they are decomposers
PROTISTS • IMPORTANCE OF PROTISTS • ECOLOGICAL ROLES • Provide an essential food base in aquatic food chains • Carry out more than 30-40% of Earth’s photosynthesis • Protozoans help keep the number of bacteria in check