DomainBacteria

DomainArchaea

DomainEukarya

Common ancestor

Kingdom: ProtistsKingdom: ProtistsDomain EukaryaDomain Eukarya

General characteristicsGeneral characteristics• Classification criteriaClassification criteria

– eukaryotes eukaryotes – not animal, plant or funginot animal, plant or fungi– Live in wet or moist environmentsLive in wet or moist environments

That’s more ofwhat they’re not

& notwhat they are!

Great DiversityGreat Diversity

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Protist DiversityProtist Diversity• The full spectrum of modes of lifeThe full spectrum of modes of life

– from unicellular to multicellular from unicellular to multicellular – autotrophic to heterotrophicautotrophic to heterotrophic– asexual to sexual reproductionasexual to sexual reproduction– pathogenic to beneficialpathogenic to beneficial– sessile to mobilesessile to mobile

Protist MotilityProtist Motility

• How they move:How they move:– flagellumflagellum– ciliacilia– pseudopodpseudopod

Kingdom Protista is REALLY Kingdom Protista is REALLY Diverse:Diverse:

• We will divide & learn them in three-We will divide & learn them in three-groups:groups:– Animal-likeAnimal-like– Plant-likePlant-like– Fungus-likeFungus-like

Animal-like ProtistsAnimal-like Protists• Aka ProtozoansAka Protozoans

– heterotrophs, predatorsheterotrophs, predators– UnicellularUnicellular

• AmoebaAmoeba• ParameciumParamecium• Stentor Stentor

Paramecium with food vacuoles stained red

Amoeba ingesting a Paramecium

Plant-like ProtistsPlant-like Protists• Plant-like ProtistsPlant-like Protists

– autotrophs, photosynthesisautotrophs, photosynthesis– Unicellular or multi-cellularUnicellular or multi-cellular

• EuglenaEuglena• Algae (green, red, brown)Algae (green, red, brown)• DiatomsDiatoms• DinoflagellatesDinoflagellates

Fungus-like ProtistsFungus-like Protists• Fungus-like ProtistsFungus-like Protists

– HeterotrophsHeterotrophs– Motile at some point in life cycleMotile at some point in life cycle– Reproduce by forming sporesReproduce by forming spores

•Water moldsWater molds•Downy MildewsDowny Mildews•Slime moldsSlime molds

Benefits of ProtistsBenefits of Protists• PlanktonPlankton

– phytoplanktonphytoplankton•small algae + diatomssmall algae + diatoms

•much of the world’s much of the world’s photosynthesisphotosynthesis

•produces ~90% of atmospheric produces ~90% of atmospheric oxygenoxygen

– zooplanktonzooplankton•heterotrophic protists + animalsheterotrophic protists + animals

•key ecological role at base of key ecological role at base of marine food web marine food web

Mmmmmm!Sounds like breakfast!

Benefits of ProtistsBenefits of Protists• PlanktonPlankton

– Food for humansFood for humans•Kelp (brown algae or “sea weed”)Kelp (brown algae or “sea weed”)

•Used to thicken foods such as ice Used to thicken foods such as ice cream or jellycream or jelly

– AbrasivesAbrasives•Diatoms (silica shells *glass)Diatoms (silica shells *glass)

•Empty shells form thick deposits that Empty shells form thick deposits that can be used for commercial items such can be used for commercial items such as pool filters, toothpaste, sparkling as pool filters, toothpaste, sparkling paintpaint

– Also natural pest control for slugs & fleas Also natural pest control for slugs & fleas

Protists can also be HarmfulProtists can also be Harmful• Phytophthora infestansPhytophthora infestans• Great Potato FamineGreat Potato Famine

– killed nearly a million people in Ireland in 1846–killed nearly a million people in Ireland in 1846–18471847

– water mold virtually wiped out the country’s water mold virtually wiped out the country’s potato crops, which were an essential staple in potato crops, which were an essential staple in the Irish diet (sometimes the only food on the the Irish diet (sometimes the only food on the table.)table.)

..

• Red Tides occur when Red Tides occur when enormous blooms are enormous blooms are triggered by an upwelling of triggered by an upwelling of nutrients from the water’s nutrients from the water’s depths during warmer depths during warmer seasons.seasons.

• Population can jump to Population can jump to more than 20 million cells more than 20 million cells per liter of sea water along per liter of sea water along some coasts during these some coasts during these blooms, turning the water a blooms, turning the water a reddish hue.reddish hue.

• Produces deadly toxin that Produces deadly toxin that can be passed to humans can be passed to humans from fish/shell fish that from fish/shell fish that consume them causing consume them causing illness/death.illness/death.

After encountering and absorbing a red tide..a stingray becomes disoriented. They have the appearance of not being able to see or control what they are doing. Eventually the ray will stay at the surface lying horizontally and die.

Protists & DiseaseProtists & Disease• Parasitic & pathogenic ProtistsParasitic & pathogenic Protists

– malariamalaria– GiardiaGiardia– trypanosomestrypanosomes

Plasmodium

Giardia

Trypanosoma

Any Questions??