01:119:116 Lecture Notes - Lecture 10: Symbiogenesis, Cambrian Explosion, Electron Microscope
3 Dec 2017
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2nd: photosynthetic autotrophs: e from sunlight- ex: cyanobacteria: released o2. Stromatolites: bacterial mats on sedimentary layers- 3,5 bya- just heterotrophic bacteria. 3rd: aerobes: use o2-> more atp: origin of eukaryotes- oldest fossils: 1. 8 bya. An endosymbiont: cell lives within a host cell- serial endosymbiosis- mito entered first, The endosymbiont theory: mitochondria + plastids were small prokaryotes- some eukaryotic came and ate it and instead of digesting, they evolved plastids second own dna, have ribosome and undergo binary fission->> similar to prokaryotes. Evidence- both mitochondria and plastid: inner membranes have enzymes, small, have: origin of multicellularity. Cambrian explosion: 535-525 mya- fossils appear resembling modern animal, rapid evolution new animal body plans: colonization of land- 500 mya- larger forms of life on land- fungi, plants, and animals- Adaptations for life on land- prevent drying out. Topic 5- cell structure and a common evolutionary ancestor. Cells- smallest unit of life- multicellular organisms = cooperative specialized cells.
