Eukaryotes, most are unicellular, some form colonies, some are coenocytic=lots of cytoplasms
Nucleus surrounded by nuclear envelope, contain plastids and mitochondria, 9+2 flagella
Some are multicellular, relatively simple body forms.
Movement by pseudopodia, flexing over cells, gliding, waving cilia, flashing flagella
Nutrients: autotrophic/heterotrophic (photosynthesis, absorption, ingestion)
Mutualism, Commensalism: one benefits, Parasitism: one depends on the other.
Most protists are aquatic, make up most of plankton
Protists don’t develop multicellular reproductive organs.
Protists (i.e. zooflagellates): first eukaryotic cells to evolve from ancestral prokaryotes.
Eukaryotic organelles arose from symbiotic rel’s between larger cells/smaller prokaryotes
Mitochondria arose from aerobic bacteria (rRNA from mitochondria matches purple bacteria)
Cyanobacterium + host cell (primary endosymbiosis) = chloroplasts
Chloroplasts provided nonphotosynthetic eukaryotes chloroplasts during secondary endosym.
3 mems envelop chloros of euglenoids & dinoflagellates, 4 with diatoms & green/brown algae
Apicomplexans (protists that cause malaria) (Plasmodium) have nonfunctional chloroplasts
Chloroplasts surrounded by 4 membranes
Drugs that inhibit chloroplasts also kill plasmodium
Molecular & ultrastructure research
phylogenetic relationships amongst protists
Molecular data obtained for the gene that code for SSU rRNA in different eukaryotes
Ultrastructure = fine details of cell structure revealed by electron microscopy
Similar structural patterns suggest certain taxa are monophyletic
Water molds, diatoms, golden algae, brown algae = all monophyletic
Protist Kingdom =
Paraphyletic (some descendants of a common eukaryotic ancestor)
Eight Major Clades: excavates, discicristates, alveolates, heterokonts, plants, cercozoa,