BIOLOGY 1M03 Chapter Notes - Chapter 9: Oligocene, Pleistocene, Kenyapithecus
15 Dec 2012
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O18 h2o is heavier and more prevalent in warmer climates. Different techniques work for different periods: potassium-argon dating used to figure out age of volcanic rock near. Soon as animal dies c14 will convert to n14 at constant rate <40000 y: thermo-luminescence dating- high-energy particles dislodge electrons from orbit and trap them elsewhere in rock lattice. Heating a rock relaxes the bonds holding the e- and they are recaptured by the atoms giving off light. Using data of density of high-energy particles, can estimate length of time since rock ex. flint was burned: electron-spin-resonance dating- used to determine age of apatite crystals (inorganic component of tooth enamel that forms as teeth grow). Electrons are trapped in it, and subjecting to a variable magnetic field can allow estimating number of electrons trapped in the teeth. Iii: evolution of angiosperms (evolved after gymnosperms) created a new set of ecological niches. Primates were one of animals to fill these niches.
