Protista Notes

Eukaryotic organisms with unicellular, multicellular, or colonial cell organization.
Primarily aquatic, related to plants, fungi, or animals but distinct.
The kingdom Protista has been largely abandoned; lineages are now recognized as kingdoms.
Size ranges from nanometers to meters.

Locomotion via cytoplasmic extensions (pseudopodia), gliding, flexing, cilia, or flagella.
Nutrition can be autotrophic, heterotrophic (absorbing or ingesting), or a combination.
Interaction ranges from free-living to mutualistic, commensal, symbiotic, or parasitic.
Reproduce asexually, with sexual reproduction involving gamete union without multicellular reproductive organs.

Amoeboid plankton with reticulating pseudopods.
Produce tests (shells) of calcium carbonate ( $CaCO_3$ ) or agglutinated sediment.
Fossils used in biostratigraphy for relative dating of rocks and oil deposit identification.
Serve as bioindicators in coastal environments, susceptible to ocean acidification.

Marine plankton with axopods for feeding.
Some contain algal endosymbionts.
Radiolarians secrete silica shells that form ooze on the ocean floor after death.

Spherical or elongated with flagella.
Heterotrophic, feeding via engulfing with pseudopodia or through an oral groove.
Can be free-living or endosymbionts.
Example: Trichonymphs in termites digest cellulose in wood.
Parasitic zooflagellates, such as trypanosomes, cause diseases like African sleeping sickness.
Giardia intestinalis is a common contaminant causing intestinal issues.
Choanoflagellates are marine and freshwater organisms with a flagellum surrounded by microvilli.

Parasites with infectious sporozoites.
Possess an apical complex for penetrating host cells and apicoplasts for fatty acid synthesis.
Require two or more hosts to complete life cycle.
Example: Plasmodium sp. causes malaria, transmitted by Anopheles sp. mosquitoes.

Use cilia for movement and feeding.
Have a pellicle for flexibility and coordinated ciliary movements.
Ingest bacteria or tiny protists through an oral groove.
Contractile vacuoles regulate water balance.
Have macronuclei (feeding, waste removal) and micronuclei (sexual reproduction).
Asexual reproduction via binary fission; sexual reproduction via conjugation.

Autotrophic, ranging from unicellular to multicellular (seaweeds).
Habitats are damp and wet environments.
Reproduction can be sexual or asexual.
Classification based on photosynthetic pigments, flagella, energy reserves, cell wall composition, and chloroplast structure.
Includes Euglenoids, Dinoflagellates, Diatoms, Golden Algae, Brown Algae, Green Algae, and Red Algae.

Unicellular, with intracellular cellulose plates.
Two flagella: one transverse, one longitudinal.
Photosynthetic pigments: chlorophyll a, chlorophyll c, and fucoxanthin.
Heterotrophic via ingesting microorganisms.
Some are endosymbionts (zooxanthellae).
Asexual reproduction via longitudinal cell division.
Red tides are caused by population explosions and produce toxins harmful to aquatic life.

Unicellular with silicate cell walls.
Two groups: Centrales (radial symmetry) and Pennales (bilateral symmetry).
Move by gliding, facilitated by slimy secretions.
Photosynthetic pigments: chlorophyll a, chlorophyll c, and carotenoids (fucoxanthin).
Energy reserves: oils or chrysolaminarin.
Asexual reproduction by shell division; sexual reproduction triggered by size reduction.
Important in food webs and oxygen production.
Diatomaceous earth is used as a filtering agent.

Unicellular or colonial, biflagellated.
Cells covered with silica or calcium carbonate scales.
Photosynthetic pigments: chlorophyll a, chlorophyll c, and carotenoids (fucoxanthin).
Heterotrophic via ingesting bacteria.
Energy reserves: oils or carbohydrates.
Asexual reproduction via zoospores.
Important producers in marine ecosystems.

Autotrophic with diverse body shapes.
Unicellular, multicellular, multinucleate, and colonial forms.
Similarities with plants: cellulose cell walls, starch energy reserves, chlorophyll a, chlorophyll b, and carotenoids.
Differ from plants: lack differentiated tissues; require watery habitats.
Move via flagella; some are nonmotile.
Asexual (binary fission, fragmentation, zoospores) and sexual reproduction; alternation of generation.

Multicellular seaweeds.
Vary in size and shape.
Leaflike blades, stemlike stipes, and rootlike holdfasts.
Gas-filled bladders for buoyancy.
Photosynthetic pigments: chlorophyll a, chlorophyll c, and carotenoids (fucoxanthin).
Energy reserves: laminarin.
Asexual (zoospores) and sexual reproduction; alternation of generation.
Commercially used as thickening agents; provide iodine as a food source; act as primary producers and habitats.

Multicellular, interwoven filaments.
Attach via holdfast.
Alternation of generations.
Non-flagellated gametes.
Photosynthetic pigments: phycoerythrin, phycocyanin, chlorophyll a, chlorophyll b, and carotenoids.
Energy reserves: floridean starch.
Agar and carrageenan are used as food thickeners and additives.
Source of vitamins and minerals; ecologically important in coral reefs.

Protists that resemble fungi; saprophytic with hyphae.
Cell walls made of cellulose; cells contain centrioles.
Habitats: wet and damp areas.
Include Plasmodial Slime Molds (Myxomycota), Cellular Slime Molds (Acrasiomycota), and Water Molds (Oomycota).

Form plasmodium, a multinucleate mass that ingests bacteria and organic matter.
Under unfavorable conditions, produce sporangia via stalked structures. Meiosis occurs within sporangia, spores are produced.
Spores germinate into swarm cells (flagellated) or myxamoeba (amoeboid).
Swarm cells and myxamoeba fuse to form a zygote, which develops into plasmodium.
Example: Physarum polycephalum.

Exist as individual amoeboid cells during feeding stage.
Under unfavorable conditions, cells aggregate in response to cAMP, forming a pseudoplasmodium (slug).
The slug develops into a stalked fruiting body with asexual spores.
Spores release haploid amoeboid cells.
Example: Dictyostelium discoideum.

Resemble fungi; have hyphae (coenocytic) forming a mycelium.
Cell walls of cellulose, chitin, or both.
Asexual reproduction via zoosporangium producing zoospores.
Sexual reproduction via antheridium and oogonium forming a zygote, which develops into oospores.
Example: Phytophthora infestans.