BIO SCI 1A Lecture Notes - Lecture 5: Biogeography, Mesozoic, Cenozoic
5 Mar 2016
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The fossil record does not give us a good picture of species that have ever lived biased towards the marine species, and hard shelled species, recent vs. distant past. Law of large numbers with a very large population, just about anything will happen. For example, most people will believe in things that have been accepted. We can only talk about the relative age of a fossil until radiocarbon dating. It is the use of radioactive isotopes to date fossils. Radioactive isotopes decay in a regular pattern during successive, equal periods of time. Radioactive decay: is the loss of neutrons at a regular rate that is isotope-specific. It is one or more forms of a chemical element with the same number of protons but a different number of neutrons. Decay rate is constant, and not affected by pressure, temperature, etc. Reminder: rate of decay expressed as half life-amount of time it takes for one half of atom to decay.
