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Key Life Events in Earth History
•.0001 billion: homo sapiens•.003 billion: earliest human
ancestors evolve•.065 billion: K/T impact,
dinosaurs extinct,
mammals takeover
•.10 billion: flowering plants evolve•.25 billion: P/T mass extinction•.45 billion: land plants spread•.65 billion: multi-celled life•2.4 billion: oxygenated oceans•3.2 billion: Photosynthesis•3.5 billion: First life in oceans•4.5 billion: Earth forms
Effects of Continental Drift on Climate
Nature 279, 712 - 713 (21 June 1979); doi:10.1038/279712a0Albedo contrast and glaciation due to continental drift
J. GRAHAM COGLEY, Department of Geography, Trent University, Peterborough, Ontario, Canada A popular theory1,2 holds that glaciation occurs when land-masses drift over the poles and cool the Earth. However, the Earth cools on balance when landmasses bunch in the tropics, rather than over the polar caps. I suggest here that a peculiar distribution of land may thus be required during glacial periods, perhaps explaining their rarity3 and the long intervals when land was over the poles but the Earth was not glaciated4.