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