01:119:116 Lecture Notes - Lecture 2: Green Algae, Red Algae, Golden Algae
5 May 2015
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Endosymboisis: relationship btw 2 spp in which 1 organism lives inside another organisms. Throughout evolutionary history one organism has engulfed another to mutual benefit of both. Serial endosymbiosis: proposes key euk organelles evolved thorugh seq of endosymbiotic events. =phagocytosis of a bacterium by another cell: 2 key euka organelles: Mitochondria of all euka descended from 1 ca. Mitochondria arose only once over course of evolution. Group of closely related organelles of photosynthetic euka. Lineage gave rise to 2 lineages of photosynthetic protists: red algae and green algae. Host cell from primary endosymbiosis engulfed by another cell. Read algae and green algae underwent secondary symbiosis: occurred frequently. Protists are euka cells: have organelles+ are more complex than proka cells. Huge euka diversity: new data+ rapidly changing hypotheses. Root of euka tree not known: 4 supergroups diverging simultaneously from 1 ancestor. =polytomy: not correct don"t know which organisms diverged 1st. Name means the very 1st : thought to be 1st euk cells.
