PPT 1 Protists

Protists

Eukaryotic microorganisms
Include protozoa, algae, slime/water molds

Not plants animals or fungi

Have nucleus, organelles, more complex than prokaryotes

They evolved through Endosymbiosis where a cell engulfs another cell which becomes a permanent symbiont

Usually unicellular but can be colonial or multicellular

Can be parasites, predators, or photosynthesizers

The 4 Supergroups

Excavata

SAR (Stramenopiles, Alveolates, and Rhizarians)

Archaeplastida

Unikonta

Supergroup Excavata

ventral feeding groove

modified mitrochondria

unique flagella

cytoskeleton

has multiple clades (common ancestor + descendants)

diplomonads

parabasalids

euglenozoans

Excavata Diplomonads + Parabasalids

Diplomonads have 2 equal sized nuclei

lack plastids

modified mitochnodra

multiple flagella

mostly anaerobic

mostly parasitic

How did protists evolve? Endosymbiosis

Prokaryotic cell may have engulfed a aerobic bacterium which formed an early heterotrophic eukaryote and formed a mitochondrion organelle

May have also engulfed a photosynthetic bacterium that allowed for plastids to form

We think it may have happened twice, causing cyanobacterium to be absorbed in Primary endosymbiosis, splitting off into red and green algae, where secondary endosymbiosis happened and splitting off into more species

Exccavata Euglenozoans

one or two flagella

can be mixtropic, both hetero and autotrophic