2Protists Protists – eukaryotes; more complex than prokaryotes. 1st – unicellular - called protists – in 1 big kingdom (Protista)Protista - unicellular eukaryotes that are not plants, fungi, or animals.
6Protists divided into 3 categories. 1Protozoa- ingestive, animal-like.2Absorptive, fungus-like protists.3Algae -- photosynthetic, plant-like protists.Most move with flagella, cilia at some time in life cycle.Flagella - extensions of cytoplasm.
8Cilia shorter, more numerous than flagella. Both move cell with rhythmic power strokes, like oars of boat.Reproduction and life cycles highly varied among protists.
9http://sja. ednet. ns. ca/fixed%20protista%20worksheet_files/image006
10Some reproduce asexual; can shuffle genes through syngamy (union of 2 gametes. Others primarily asexual; can reproduce sexually occasionally.Many protists form resistant cells (cysts) - can survive harsh conditions.
12Protists found wherever there is water (oceans, ponds, lakes); also damp soil, leaf litter, moist terrestrial habitats.Protists - important parts of plankton, communities of organisms that drift passively or swim weakly in water.
16OriginEvolution of eukaryotic cell led to development of unique cellular structures and processes.Smallness of prokaryote limited amount of metabolic activity.Evolution of multicellular prokaryotes - cells specialized for different functions.
18Some form groups that had specialty or have compartments for each activity (evolution of eukaryotes) Plasma membrane infolded, creating organelle membranes in eukaryotes.Chloroplasts, mitochondria evolved from endosymbiotic relationships.
20Serial endosymbiosis - mitochondria and chloroplasts - small prokaryotes living within larger cells. Ancestors of mitochondria - aerobic heterotrophic prokaryotes.Ancestors of chloroplasts - photosynthetic prokaryotes.
28Plastids diversified because of endosymbiotic relationships. Secondary endosymbiosis -heterotrophic protist engulfed algae containing plastids.Led to diversification of plastids (including chloroplasts).
433KinetoplastidsKinetoplastids (Kinetoplastida) have single large mitochondrion associated with unique organelle (kinetoplast)Kinetoplastids symbiotic, include pathogenic parasites.Trypanosoma causes African sleeping sickness.
49Red tides caused by dinoflagellates in bloom. Color comes from pigment they produce.Produce toxins deadly to predators and humans.1 species - carnivorous; produces toxin to stun fish, then eats flesh.
545ApicomplexansApicomplexans - parasites of animals; some cause serious human diseases.Spores (sporozoites) - infectious.Plasmodium - protist that causes malaria; spends part of life cycle in mosquitoes, part in humans.
627StramenopilaIncludes heterotrophic and photosynthetic protists; presence of numerous fine, hairlike projections on flagella.Heterotrophic stramenopiles – oomycotes - water molds, white rusts, downy mildews.
64Water molds important decomposers, mainly in fresh water. Form cottony masses on dead fish.Some water molds parasitic, growing on skin, gills of injured fish.White rusts and downy mildews parasites of terrestrial plants.
729SeaweedLargest marine algae - brown, red, and green algae - seaweeds.Inhabit intertidal and subtidal zones of coastal waters.Body of seaweed – thallus - consists of rootlike holdfast + stemlike stipe - supports leaflike photosynthetic blades.
8210Rhodophyta Red algae - no flagellated stages in life cycle. Red coloration visible due to accessory pigment phycoerythrin.Red algae (Rhodophyta) - most common seaweeds in warm coastal waters of tropical oceans.
84Some species that live down deep have special pigments - allow them to absorb blue and green wavelengths (only ones that penetrate bottom).Most red algae multicellular - some reaching size large enough to be “seaweeds.”
8811ChlorophytaGreen algae (chlorophytes) named for grass-green chloroplasts - similar to plants.Most of the species chlorophytes live in freshwater.Most green algae have both sexual and asexual reproductive stages.
97Most heliozoans (“sun animals”) live in fresh water. Skeletons made of glass.Foraminiferans, (forams) almost all marine.Shells have pores in them.Pseudopodia extend through pores for swimming, shell formation, feeding.
9912MycetozoaMycetozoa (slime molds or “fungus animals”) neither fungi nor animals - protists.Slime molds feed and move via pseudopodia but comparisons of protein sequences place slime molds close to fungi and animals, not amoeba.
103Cellular slime molds (Dictyostelida) straddle line between individuality and multicellularity. Feeding stage consists of solitary cells.When food scarce, cells form aggregate (“slug”) - functions as unit.Dominant stage - haploid stage.