01:070:111 Lecture Notes - Lecture 17: Depauperate Ecosystem, Ordovician, Gravity Anomaly
27 Mar 2018
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Document Summary
End cretaceous- first mass extinction to be studied in depth. 11 years- extinction of dinosaurs due to asteroid. Big claims need a lot of support, need to be able to be replicated. Chicxulub crater- found by gravity anomaly mapping. The more massive and dense the object, the more force that gravity exerts on it. Pattern found similar to ripples (rings) made by areas of less and more gravity. Start with and bet 25 cents for each round. True randomness means every outcome has an equal probability of occurring. Rare- mass extinction when species experience different circumstances. Pulse versus press extinction- differ by time scale. Press- sustained period of conditions elevating extinction. Randomly depauperate- less biodiversity, less species but random pattern. Adaptively changed- lots of species went extinct but the lineages of those species have changed over time. Sorted- species that are left over are special/different.
