Characteristics of Protists Are unicellular or simple multicellular

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Characteristics of Protists • Are unicellular or simple multicellular • Eukaryotic • Not plants,

Characteristics of Protists • Are unicellular or simple multicellular • Eukaryotic • Not plants, fungi or animals • Many are autotrophs and others are • • • heterotrophs Use flagella, cilia or pseudopodia for locomotion Reproduce asexually Reproduce sexually by conjugation

Animal-like Protists • Sometimes called protozoa Amoeba • Have pseudopodia that are large, rounded

Animal-like Protists • Sometimes called protozoa Amoeba • Have pseudopodia that are large, rounded cytoplasmic extensions that function both in movement and feeding • Moves by amoeboid movement-cytoplasmic streaming • Prey on smaller protists and bacteria • Live freely , some live in human intestines and cause disease (ulcers)

Amoeba

Amoeba

Animal-like cont… Paramecium • Move by cilia • Found in ponds and slow moving

Animal-like cont… Paramecium • Move by cilia • Found in ponds and slow moving streams that contain plants and decaying organic matter • Asexual-binary fission • Sexual-conjugation (exchange genetic material with the micronucleus)

Animal like protist

Animal like protist

Animal-like…. Sporozoans • Animal parasites (complex life cycle and usually need 2 host) •

Animal-like…. Sporozoans • Animal parasites (complex life cycle and usually need 2 host) • Plasmodium causes malaria and needs both mosquitoes and humans • Absorb nutrients and destroy host cells • May have killed more people than any other group of pathogens

Malaria life cycle • Begins life cycle in mosquito and transfers to a human

Malaria life cycle • Begins life cycle in mosquito and transfers to a human • Attacks healthy red Blood cells

Animal-like… • Trypanosomes live in the blood of fish, amphibians, reptiles, birds and mammals

Animal-like… • Trypanosomes live in the blood of fish, amphibians, reptiles, birds and mammals and are carried from host to host by blood sucking insects • Tsetse fly which lives only in Africa transmits these parasites causing sleeping sickness (increasing fever, lethargy, mental deterioration and coma)

Plantlike Protists • Most are known as algae • Have chloroplasts and produce their

Plantlike Protists • Most are known as algae • Have chloroplasts and produce their own carbohydrates by photosynthesis but have no true roots, stems or leaves. • Examples: green algae, brown algae, red algae, diatoms, dinoflagellates, golden algae and euglenoids.

Multicellular algae

Multicellular algae

Euglena

Euglena

Dinoflagellates – Cause red tide

Dinoflagellates – Cause red tide

Plantlike… Euglenoids • Both plantlike and animal-like • Most are autotrophic but lack a

Plantlike… Euglenoids • Both plantlike and animal-like • Most are autotrophic but lack a cell wall • Highly motile • Live in fresh water, but a few occupy moist environments such as soil or the digestive tracts of certain animals

Funguslike protists (Slime Mold) • Live as individual haploid cells that move about like

Funguslike protists (Slime Mold) • Live as individual haploid cells that move about like amoebas • Move as an independent organism, creeping over the ground or swimming in fresh water and ingesting food but when short on food, will cause them to gather together by 1000’s • Produce fruiting bodies that resemble those of fungi

Slime mold

Slime mold

Funguslike (water molds) • Some are parasitic with fish • Similar means of obtaining

Funguslike (water molds) • Some are parasitic with fish • Similar means of obtaining nutrients, cell walls made of the same type of material, filamentous bodies and similar enzymes and biochemical pathways • Some biologists hypothesize that chytrids (water mold) are a link between protists and fungi

Water mold on a potato

Water mold on a potato

Protists and Humans • Produce larger amounts of oxygen, form the foundation of food

Protists and Humans • Produce larger amounts of oxygen, form the foundation of food webs, recycle materials and play a role in several symbiotic relationships • Algal blooms can lead to the depletion of oxygen in water. Red tides produce harmful toxins

Protists and humans • Can help scientists understand the movement of leukocytes (White blood

Protists and humans • Can help scientists understand the movement of leukocytes (White blood cells), provide food and provide important byproducts, such as alginate and agar • Parasitic protists cause malaria, giardiasis (diarrhea, intestinal cramps), cryptosporidiosis (intestinal cysts), trichomoniasis (STD)