Biology 1002B Lecture : lecture notes
10 Feb 2012
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Scottish geologists james hutton argued that slow and continuous physical processes, acting over long period of time,produced earth major geologic features. Hutton s gradualism , the view that earth changed slowly over its history. In environments where oxygen is scarce, decomposition does not occur and even soft-bodied organisms may be preserved. Radiometric dating involves the use of isotopes and sometimes allows actual ages (with error bars) to be associated with different rock strata. Isotopes decay at steady rates ; thus, rocks containing isotopes can be dated when the amounts of isotopes can be measured and the rates of decay are known. To date sedmentary fossils , scientists determine the age of volcanic rocks from the same strata. Anagenesis i s the accumulation of changes in a lineage as it adapts to changing environments. Cladogenesis- the evolution of two ore descendant species from a common ancestor.
