BILD 3 Lecture Notes - Lecture 15: Allele Frequency, Radiometric Dating, Alpheidae
30 May 2016
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Document Summary
Isotopes: varieties of an element with different numbers of neutrons in the nucleus such as: Carbon 14 will become nitrogen because of its radioactivity. They decay spontaneously into other elements or isotopes at a particular, constant rate. Time interval after which half the atoms of a particular radioactive isotope will have decayed into the daughter isotope. For uranium dating, the clock starts when rock solidifies. We can use the uranium dating and the principle of stratigraphy to come to an absolute age of the fossils. For carbon dating, the clock starts when death happens. Experiments have shown that energy in an atmosphere of those gases can abiotically make amino acids, nucleotides, sugars. Miller and urey (1953) heated and cooled water vaper + methane + ammonia + hydrogen. If the environments differ, natural selection will change allele frequencies differently in each population (adaptation) Genetic drift will result in the fixation and loss of different alleles in the population.
