BIO 124 Lecture Notes - Lecture 18: Brown Algae, Red Algae, Plastid
16 Mar 2016
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Ch 25 class notes: eukaryotes arose by endosymbiosis 1. 8 ba, mulicellularity has come up muliple imes in eukaryotes, 4 super groups of eukaryotes based on morphological molecular data. Chemical evidence (peaks and valley in chemical life in fossil record - signs) about 2. 7 ba but true fossil record is 1. 8 ba. First large, mulicellular eukaryotes were edicarian biota - pushed organismal steps forward. 600 mya irst large mulicellular eukaryote - needs more energy, needs specializaion for funcions. Greater structural complexity about 1. 5 ba and keep diversifying. Ice ages probably hindered rise of eukaryotes but prokaryotes have the ability to survive. Bacteria gives mitochondria (archaea did not) and mostly bacteria give metabolic genes that were then passed on to eukarya. Endosymbiont theory: mitochondria and plasids used to be small prokaryotes engulfed by bigger cells and they then develop a beneicial relaionship to both o o o. Endosymbiont: cell that lives within a host cell.
