Protists The first Eukaryotes
Origin of Eukaryotic Cells Endomembrane system- developed from infolding of plasma membrane. Evolutionary advantage? compartmentalization, microenvironments, increased membrane surface area
Endosymbiotic Theory Inside together living. Plastids and mitochondria are a result of the endocytosis of bacteria by larger cells of the lineage that become eukaryotes. All eukaryotes got mitochondria only some got chloroplasts.
Endosymbiotic Theory Evidence 1) C & M have their own DNA ( circular, no histones) 2) C & M have their own ribosomes (small like bacteria) 3) C & M have 2 membranes (outer like eukaryote, inner like bacteria) (homologous transport proteins) 4) C & M replicate on their own 5) Endosymbiosis observed where prey or parasites become mutualistic symbionts
Endosymbiotic Algae
Importance of Protists Large component of photosynthetic plankton Diatoms, dinoflagellates, Many are Endosymbionts Cause human disease: Giardia (hikers diarrhea), Trichomonas (STD), Trypanosoma (sleeping sickness), plasmodium (malaria), Secondary endosymbiosis of red or green algae create chloroplasts with 4 membrane layers
Protists = Eukaryotes that are not Plant, Animal or Fungus 1) Most are unicellular 2) None have true tissues (so not plant, animal or fungi) 4) Some animal-like(ingest food), some plant-like(photosynthetic ) some Fungus-like (absorptive) 5) Paraphyletic group so not a kingdom (share a common ancestor but does not include all the descendants of that ancestor)
Amoeba Structures to know A) nucleus B) contractile vacuole removes water C) food vacuole D) pseudopod B C A D
Euglena A) flagella B) reservoir C) contractile vacuole D) pellicle : (contractile memb.) E) eye spot A B E C D
A) contractile vacuole B) food vacuole C) macronucleus D) micronucleus E) pellicle F) cilia G) oral groove H) gullet G H
Amoebozoans Move by flowing cytoplasm into projections of cell membrane called pseudopods false feet Example: Amoeba Branch that lead to Metazoa & fungi (animals)
Most primitive Clade Parabasalids & Diplomonads T.vaginalis Giardia STD hiker’s diarrhea Anaerobic or low O2, mitochondria primitive/lacking Form cysts to survive hostile environments
Cilliates Have trichocysts and cilia Earliest example of ‘true’ sexual reproduction = conjugation Example : Paramecium
Dinoflagellates Phytoplankton with flagella Chloroplasts resemble green or red algae Secondary endosymbiosis
Dinoflagellates Some bioluminsecent Some endosymbionts in Cnidarians Dinoflagellate blooms: Caused by high N +P level May result in Red tide May result in Eutrophication
Apicomplexans apical complex of microtubules All are Parasites use microtubules to pierce host Don’t move on their own Are carried by a vector Plasmodium sp. cause Malaria live inside human Red Blood Cells
Diatoms Yellow/brown Algae 2-part silica shells Important in phytoplankton food chain Important oxygen producer Diatomaceous earth
Diatoms = Carbon sink Diatoms are able to use Bicarbonate as a carbon source. Diatoms sinking to ocean floor act as a sink for carbon.
Brown Algae Brown pigments absorb wavelengths of light that reach deeper into the water. Largest multicellular algae Sargassum kelp
Sargasso Sea
Algae parts…
Oomycotes (egg fungi) Saprobe Stramenopiles (absorb food) parasites & decomposers Lost chloroplasts Rusts water molds
Chlorophyta Green algae (chlorophyll) Most similar to plants Unicellular …Desmids Multicellular…filamentous algae & volvox Complex life cycles
Red Algae Red pigments absorb wavelengths of light even deeper in the water. (green & blue) phycobilins Used to make thickeners & agar Multicellular Complex life cycles
amoebozoans Complex life cycles Closest to Animals and Fungi All have pseudopods Free-living Amoeba, slime molds, & parasites Free-living & Slime molds important decomposers
Plasmodial Slime mold
Cellular Slime Molds - cAMP