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Download History of Life - MrsSconyersLabBiology
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History of Life Ch. 17 Fossils • Remains of ancient life • Fossils are used to analyze similarities and differences between ancient and living organisms • It shows us change over time in species Relative Dating • Puts fossils in order of time – not exact dates • The bottom layers contain older fossils Radioactive Dating • Can determine numerical age • Half-life – length of time required for half the radioactive sample to decay • Radiocarbon dating – Carbon-14 decays into nitrogen-14 – The more carbon-14, the younger it is Radiocarbon dating • Carbon-14’s half life is 5730 years • Practice – Begin with 1000g of carbon-14 – After 1 ½ life how much is left? – After another ½ life how much is left? – How much will be left after 4 half-lives? – How long is 4 half-lives?
