Biology 2581B Lecture Notes - Lecture 3: Alphaproteobacteria, Symbiosis, Prokaryote
29 Mar 2017
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Focus on transition from prokaryotic to complex life. Now think about the intermediates between these two things. A long time ago, a bacterium found its way in the eukaryotic domain. The importance of endosymbiosis: hypothetical example. Both free-living unicellular and both have a genome. Organism a feeds on b (feeding [i. e. , endocytosis/phagocytosis] is a complex behaviour and cannot be performed by most known bacteria) Organism b is undigested and inside a. B starts providing a benefit to a or vice versa. Host is a and b is symbiont. What if there was gene a that allows b to be free-living outside of a. And what if a random mutation knocks out that gene. As long as b is inside a, it is ok, but not out of a. A genetic change that increases the complexity of a biological system and that is hard to undo. Turns one way and doesn"t turn back the other way.
