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Kingdom Protista. Kingdom Characteristics. • Eukaryotic • Mostly unicellular (microscopic) some are multicellular • Autotrophic, Heterotrophic, and both • Most reproduce asexually, but some can use conjugation (exchange of genetic material) • Cell wall may or may not be present
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Kingdom Characteristics • Eukaryotic • Mostly unicellular (microscopic) • some are multicellular • Autotrophic, Heterotrophic, and both • Most reproduce asexually, but some can use conjugation (exchange of genetic material) • Cell wall may or may not be present • Taxonomic Misfits– • Contains all eukaryotic cells that can’t be classified as plant, animal or fungus
Evolutionary Importance • Protists are considered to be the ancestors of the three multicellular kingdoms—fungi, plant, animal
Major Divisions of Protists • Plant-like Protists (Algae) • Animal-like Protists (Protozoans) • Fungus-like Protists (Slime Molds)
Plant-like Protists—Algae • Autotrophic • Contain cell walls • Most are immobile—some are mobile
Examples of Plant-like Protists:Green, Red, and BrownAlgae Cellular Organization: – Multicellular (Red and Brown) Green algae can be either • Nutrition: • Photosynthetic (Autotrophic) • Locomotion: • Non-motile • Habitat: • Red Algae: Marine • Green Algae: Fresh, Marine, Soil • Brown Algae: Marine • Classified by their pigment • Green, Red, or Brown (kelp) Algae • Used in many foods such as pudding, jelly, jelly beans, ice cream, marshmallows, salad dressing
Diatoms • Cellular Organization: – Unicellular • Nutrition: – Autotrophic • Locomotion: - Non-motile • Habitat: – Fresh and Marine • Shells made out of silica (glass-like)
Euglenoids • Cellular Organization: – Unicellular • Nutrition: – Heterotrophic/Autotrophic • Locomotion: - 1 or 2 Flagella • Habitat: – Aquatic • Ex: Euglena
Animal-like Protists– a.k.a. Protozoans • Heterotrophic • All are unicellular • None contain cell walls • Most can move: – Cilia- hair-like projections – Flagella- whip-like tail – Pseudopod- “false foot”
Sarcodines- Ameoba • No cell wall gives them flexibility • Cellular Organization: – Unicellular • Nutrition: – Heterotrophic • Locomotion: -Pseudopods • Habitat: – Fresh and salt water • Some may cause disease (they are parasites)
Flagellates • Cellular Organization: – Unicellular • Nutrition: – Heterotrophic • Locomotion: -flagella • Habitat: -free living and parasitic • Ex: Trypanosomes causes AfricanSleepingSickness
Ciliates • Cellular Organization: – Unicellular • Nutrition: – Heterotrophic • Locomotion: - cilia • Habitat: - fresh water and marine • Ex: Paramecium, Vorticella and stentor
Sporozoans • Cellular Organization: – Unicellular • Nutrition: – Heterotrophic • Locomotion: -Non-motile • Habitat: -parasitic • Ex: – Plasmodium-Malaria
Fungus-like Protists- slime molds • Heterotrophic decomposers • Contain cell walls • Multicellular • Exist in different forms and produce spores • Reproduce by forming spores • 3 types:water molds, downy mildews, and slime molds
Slime Molds • Cellular Organization: – Multicellular • Nutrition: – Heterotrophic • Locomotion: - amoeboid movement • Habitat: - cool, moist, shady places
Watery/Downy Molds • Cellular Organization: – Multicellular • Nutrition: – Heterotrophic (either parasites or feed on dead organic matter) • Locomotion: - amoeboid movement • Habitat: -cool, moist, shady places • Cause of the Irish potato famine in 1845-1850 that killed 1 million people
Ecological Importance of Protists • Autotrophic protists are primary component of PHYTOPLANKTON • They carry out 70 – 80% of the world’s photosynthesis • They are the base of most of the world’s food chains
Negative Contributions of Protists • Many cause disease – Malaria, sleeping sickness, amebic dysentery, etc. • Responsible for “Red Tide” that poisons shell fish • Algae blooms result in fish kills
animation Paramecium Conjugation • Two individuals line up with each other and make contact with their oral groove, • The micronucleus (2N) undergoes meiosis result-ing in four micronuclei in each of the two cells (N) • 3 micronuclei degenerate and are digested by the cell. • The remaining micronucleus in each paramecium divides once again, by mitosis. • By the time this has occurred, most of the cell membrane dividing the two cells is gone. • The two halves (originally two cells) then exchange one of their micronuclei. • The cell membrane between the two halves gets rebuilt and the two cells separate again. • The two haploid micronuclei (one original and one new) fuse into a single diploid micronucleus. • The original macronucleus, disintegrates and gets digested by the cell’s enzymes. • The micronucleus divides by mitosis to produce two identical diploid micronuclei in each individual. • One of the micronuclei then becomes the real micronucleus while the other one grows and becomes the new Macronucleus.