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Evolution

Evolution. Alan Ward. Evolution. Evolution. Formation of the Earth. Geochemical dating places the Earth ’ s age at 4.6 billion years. The oldest rocks:. SW Greenland – Itsaq Gneiss Complex (3.86 billion years old). Volcanic Carbonate Sedimentary .

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Evolution

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  1. Evolution Alan Ward

  2. Evolution

  3. Evolution Formation of the Earth Geochemical dating places the Earth’s age at 4.6 billion years The oldest rocks: SW Greenland – Itsaq Gneiss Complex (3.86 billion years old) • Volcanic • Carbonate • Sedimentary Western Australia – Warrawoona seriers; Towers formation; Pilbara supergroups South Africa – Swaziland supergroup

  4. Evolution Dinosaurs Plants invade the land Cambrian explosion Decline in phytoplankton Explosion of phytoplanckton Proterozoic first eukaryotes Stromatolites and cyanobacterria Archean Oldest fossils Oldest rocks from Isua Supercrustal Group Hadean Formation of the earth

  5. EvolutionWays of studying the origin of life

  6. Evolution Essential characteristics of Life Replication Catalysis Boundary layer RNA World Early cellular life Modern cellular life proteins take over as catalysts DNA takes over replication

  7. RNA World Replication and Catalysis Self-replicating, catalytic RNA molecules Ribozymes Modern examples RNA Self-splicing mRNA RNAse P protein Ribosomes 50S ribosome

  8. The cell – a boundary layer Lipoprotein vesicles Schrumet al., (2010) The origins of cellular life. Cold Spring HarbourPerspectBiol . Origins of Life Sunject Collection

  9. Essential characteristics of Life Energy generation FeS H2S + CO2 CH3SH FeS/NiS CH3SH + CO CH3COSCH3 CH3COSCH3 + Pi CH3CO-P + CH3SH Proton Motive Force or Substrate level phosphorylation

  10. Warm little pool

  11. RNA WorldThe ribosome is a ribozyme

  12. DNA evolution • replication infidelities • effectsof external and internal environmental mutagens (UV, O2, mutagens, …) • DNA rearrangements • acquisition of genetic information

  13. Replication- Taq polymerase

  14. Replication- Bacterial genome

  15. Lateral Gene Transfer Estimated rate of acquisition by lateral gene transfer 31 kb/Myr Point mutations introduce 22 kb of variant DNA per Myr Total acquired DNA since divergence of E. coli and S. enterica100 Myr ago 3Mb DNA different by LTG between E. coli and S. enterica 803 Kb Escherichia coli (compared to Salmonella enterica) Bacterial genomes are sampling rather than accumulating sequences, counterbalancing gene acquisition with gene loss Lawrence JG Ochman H (1997) Amelioration of Bacterial Genomes: Rates of Change and Exchange. J MolEvol (1997) 44:383–397

  16. Lateral Gene Transfer

  17. MacFadden BJ (2005)Fossil Horses— Evidence for Evolution. Science 307, 1728 – 1730

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