Bio 113 Week 5
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This 0 page Class Notes was uploaded by Paige Brabant on Tuesday February 16, 2016. The Class Notes belongs to BIO 113 at Wake Forest University taught by Anderson, Todd Michael and Clifford W. Zeyl in Spring 2016. Since its upload, it has received 19 views. For similar materials see Evolutionary and Ecological Biology in Biology at Wake Forest University.
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Date Created: 02/16/16
Paige Brabant Class Notes Evolutionary History Memorize the 14 Major Events 1 First known biological activity methanogens archaea 38 BYA 2 Photosynthesis by Cyanobacteria generates rst oxygen 35 BYA 3 Endosymbiotic origin of mitochondria 12 BYA 4 Endosymbiotic origin of chloroplasts 800 MYA 5 Origin of animals multicellularity 800700 MYA 6 Cambrian explosion origin of major animal groups 540505 MYA 7 Earliest land plants 470 MYA 8 First known land vertebrates amphibians 350 MYA 9 Permian mass extinction 250 MYA 10 First owering plants 160 MYA 11 Earliest mammals 160 MYA 12 End of cretaceous mass extinction 65 MYA 13 Major mammalian radiation 6040 MYA 14 First grasslands 22 MYA How do we gure out this timeline Earth is 46 BYA Use halflives of the best isotopes for dating 0 Ex14C l 14N halflife 5700 years Background 0 First signs of life 38 BYA o Hydrothermal vents deep sea 0 No oxygen present it would actually be toxic to the archaea o Metabolize hydrogen sul de and produce methane as a biproduct o Ecosystems in deep sea get energy by being hosts for archaea Photosynthesis by cyanobacteria 35 BYA o Stromatdites are alternating layers of cyanobacteria and mud 0 These are the rst photosynthesizing organisms and they introduce oxygen into the environment 0 They are currently in abundance in marine bay in Australia because it has a high sodium concentration and is very hot 0 The atmosphere did not contain oxygen for millions of years still because the oxygen oxidized the iron in the sea and rusted o This is why multicellular organisms didn t emerge until 800700 MYA since they need oxygen to survive First Eukaryotic Cell 12 BYA o Mitochondira and chloroplasts descended from bacteria by endosymbiosis First fossils of multicellular organisms 600 MYA o Softbodied and marine o Dif cult to decipher between plants and animals so it is dif cult to have an exact date Cambrian Explosion 540505 BYA o Aysheia wormarthropod o Hallucingenis had spines for legs 0 Anomalocarius marine predator with eyes hard mouth parts and claws Induced the rst selection for prey to not get eaten Important Points When 02 levels were at their highest giant ying insects were present because they have inef cient circulatory systems and can only grow large with an abundance of oxygen Snowball Earth 800 MYA and the conditions lasted for millions of years 0 This is known because it is the only time when sediments don t show wave marks which shows the oceans were frozen over 0 Volcanos ended snowball earth but it is not entirely clear how ln evolutionary radiation Ex Cambrian explosion 0 Most of the diversity of a clade develops relatively quickly preceeded and followed by much slower rates of diversi cation o The diversifying lineages can be species or higherlevel taxa genera families 0 Diversi cation is ecological as well as taxanomicphylagenetic new lineages have new niches
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