2Section 3: Protists What is a Protist? Protists: are eukaryotes that cannot be classified by animals, plants, or fungiAll protists live in moist surroundingsProtists are diverse because most are unicellular, but some are multicellular, some are heterotroph, and autotrophsSome protists don’t move, while others zoom around their moist surroundings
3Section 3: Protists Animal-Like Protists Like animals, animal-like protists are heterotrophs, and most are able to move from place to place to obtain foodProtozoans: animal-like protists, unicellular
4Section 3: Protists Animal-Like Protists Protozoans with Pseudopods Pseudopods: “false foot”Pseudopods form when cytoplasm flows toward one location and the rest of the organism followsAn Amoeba is an example of a protozoan that live in fresh waterSmall particles, like those of water, pass easily through the cell membrane into the cytoplasmIf excess water were to build up inside the cell, the amoeba would burstContractile vacuole: a structure that collects the extra water and then expels it from the cell
5Section 3: Protists Animal-Like Protists Protozoans with Cilia The second group of animal-like protists are the ciliatesCilia: which are hair-like projections from cells that move with a wavelike motionCiliates use their cilia to move and obtain foodThe cells of ciliates, like the paramecium has two contractile vacuoles that expel water from the cell.Has more than one nucleusProduce asexually by binary fissionWhat are cilia?
6Section 3: Protists Animal-Like Protists Protozoans with Flagella Third group is flagella which are protists that use long, whip-like flagella to moveSome live inside the body of other organismsExample: one type of flagella live inside the intestines of termitesSymbiosis: interaction between two species; a close relationship in which at least one of the species benefitsMutualism: when both partners benefit from living togetherExample: Giardia is a parasite that lives in humans; comes from wild animals such as beavers
7Section 3: Protists Animal-Like Protists Protozoans that are Parasites Fourth type is characterized by the way they live then by the way they moveThey are parasites that feed on the cells of body fluids of their hostsMany have more than one hostExample: Plasmodium: protozoan that causes malaria (disease of the blood)What is symbiosis?
8Section 3: Protists Plantlike Protists Algae: are autotrophs using the suns energy to make their own foodAlgae play a significant role in the environmentExample: algae that live near the surface of ponds, lakes, and oceans are an important food source for other organisms in the waterAlgae very in sizeUnicellularMulticellularLive in coloniesAlgae very in colorThey consists of many pigments
9Section 3: Protists Plantlike Protists Diatoms Unicellular protists with beautiful glasslike cell wallsSome float on the surface of water, some attach to rocks in shallow waterFood source for heterotrophsMove by oozing chemicals out of slits in their cell wallsWhen they die, their cell walls collect on the bottom of lakes or oceansDiatomaceous: layer forming coarse substance
10Section 3: Protists Plantlike Protists Dinoflagellates Unicellular algae surrounded by stiff plates that look like a suit of armorExists in different colors such as green or orangeGlow in the darkHave 2 flagella help in grooves between their platesWhen the flagella beat, the dinoflagellates twirl like toy tops as they move through the water
11Section 3: Protists Plantlike Protists Euglenoids Green, unicellular algae that are found mostly in fresh waterCan be either autotrophs or heterotrophsWhiplike flagellum to help it move
12Section 3: Protists Plantlike Protists Red Algae Multicellular seaweed Grow more than 260m below the ocean’s surfacePeople use red algae in many ways:Ice creamHair conditionerEat it fresh, dried, or toasted (Asian cultures)
13Section 3: Protists Plantlike Protists Green Algae Very diverse, unicellular, but some form colonies and are multicellularLive in fresh, salt water, or on land found on rocks, crevices on tree bark, or in moist soilsGreen algae and plants that live on land have similar characteristicsSame chlorophyll
14Section: Protists Plantlike Protists Brown Algae Example: seaweed, Giant kelpDifferent pigments besides brown are: green, yellow, and orangePlantlike structures: holdfasts, stalks (leaf-like structures), and gas-filled sacs called bladdersLive in cool, rock waters off the coast of the Atlantic OceanPeople eat brown algae and its used as a thickener in puddingWhat color pigments can brown algae contain?
15Section 3: Protists Funguslike Protists Spore: is a tiny cell that is able to grow into a new organismLike fungi, funguslike protists are hetertrophs, have cell walls, and use spores to reproduceSlime MoldsBrilliantly coloredLive on forest floorsOoze on the surfaces of decaying materials, feeding on bacteria and other microorganismsLife cycle: tiny amoeba-like cells, use pseudopods to feed and creep around, cells grow bigger and form a jellylike massWhen the environment conditions become harsh, the mass releases spores
16Section 3: Protists Funguslike Protists Water Molds and Downy Mildews Live in water or moist placesGrow as tiny threads and look like fuzzAttack many food crops such as: potatoes, corn, and grapesIn what environments are water molds found?