Kingdom ProtistaChapter 25

Characterisitics of Protists

• Eukaryotic • Don’t fit into any other

kingdom • Most diverse group • Animal-like, plant-like or

fungus-like • Some one cell, some

multicellular • Some autotrophs, some

heterotrophs • Most reproduce asexually

but some thru conjugation

Animal-Like Protists: Phylum Protozoa

• Heterotrophs • Prey on smaller cells –

protists, bacteria and food particles

• Cytoplasm moves and forms pseudopodia –that function in ameoboid movement and feeding

• Subphyla Sarcodina and Mycetozoa

Sarcodine feeding - amoeba

https://www.youtube.com/watch?v=W6rnhiMxtKU

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Radiolaria: silicon dioxide tests

Foraminifera:

Calcium carbonate tests (outer shell)

White Cliffs of Dover: remains of foraminiferans

Animal-Like Protists: Phylum Ciliophora

• Have cilia – movement !• Genus Paramecium

common ciliate !– Pellicle – protein layer

around cell membrane – Oral groove – contains

cilia that move food toward mouth pore

– Gullet – forms food vacuoles

– Contractile vacuoles- expand and contract to collect and expel water

Plant-like Protists• Algae • Autotrophic – photosynthetic • Why not plants? No true roots, stems or leaves • Most are aquatic • Unicellular = Phytoplankton

Phytoplankton

• Base of food web • Oxygen in

atmosphere !!!

• But there can be too much of a good thing….

Too much phytoplankton

• HABs – harmful algal blooms • Dead Zones

Phyla of Plantlike Protists

• Chlorophyta – green algae • Phaeophyta – brown algae • Rhodophyta – red algae • Bacillariophpyta – diatoms • Dinoflagellata – dinoflagellates • Chrysophyta – golden algae • Euglenophyta - euglenoids

Phylum Chlorophyta: Green• chl a and b, carotenoids • Most aquatic • Some live symbiotically

with fungi = lichen • Some live symbiotically

with coral

Calcareous Green Algae: Halimeda and Penicillus

Phylum Phaeophyta: Brown

• Chl a and c and fucoxanthin (brown) • Many multicellular • Giant Kelp • Sargassum

Phylum Rhodophyta: Red

• Chl a and phycobilins • Can live deeper –

pigments can absorb light at deep wavelengths

• Most are seaweeds • Many are coralline –

calcium carbonate “crust”

Phylum Bacillariophyta: Diatoms

• Unicellular • Two shapes: centric

and pennate • Two pieces – valves – fit

together like petri dish • Diatomaceous earth –

filters, toothpaste, abrasives

Phylum Dinoflagellata• HABs • Usually unicellular • Many bioluminesce – production of light by

chemical reaction • Ex: Noctiluca

Phylum Chrysophyta: Golden• Most freshwater, some marine • Store extra energy as oil • Formed petroleum deposits

Phylum Euglenophyta: Euglenoids

• Plant-like or Animal-like?

Phylum Euglenophyta: Euglenoids

• Chl a, b, carotenoids • Abundant in freshwater • No cell wall • Usually photosynthetic but

if grown in dark, never form chloroplasts

Fungus-Like Protists: Slime Molds and Water Molds

• heterotrophic • found on moist decaying matter

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Plasmoidal Slime Molds

• plasmodium - mass of cytoplasm as large as several meters

• creeps along eating decaying leaves and debris • if water or food is scarce - reproduces - by

spores which can tolerate harsh conditions

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Cellular Slime Molds: “social amoeba”• live as individual haploid cells that move like

amoebas • when food or water is scarce, they send out a

chemical signal that causes cells to gather by the thousands into a pseudoplasodium that looks like a slug

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Water Molds

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Disease Caused By Protists

• Malaria - from Plasmodium -(phylum Apicomplexa) - mosquito is vector - when mosquito bites, spores enter bloodstream

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Amebiasis• spread by contaminated water or food; common

in developing countries; severe diarrhea, fever, intestinal bleeding !

• caused by Protozoa

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Giardiasis

• Giardia lamblia - flagellated Protozoan

• animal feces in water • not fatal • boil, filter water

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Toxoplasmosis

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Toxoplasma protozoa