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Unformatted text preview: ow do we date fossil evidence? • • Rela9ve: fossils occur in sedimentary rocks – Older rocks occur below younger rocks Geologic forma9ons of various ages are recognized, and o^en named, by the fossils they contain – Can use this to match geologic layers from diﬀerent parts of the world Absolute: – Radioisotope da9ng • E.g. carbon for fossils < 50,000 years old • 14C/12C ra9o in all living organisms is roughly constant – But when organisms die, they stop gebng 14C from the environment and 14C/12...
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This note was uploaded on 02/18/2010 for the course BIO 201 taught by Professor True during the Spring '08 term at SUNY Stony Brook.
- Spring '08