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Unformatted text preview: BIOLOGICAL SCIENCE 102 ANIMAL BIOLOGY VOCABULARY &amp; NOTES 1 RADIOMETRIC DATING ISOTOPE = an element with a different number of neutrons as compared to the parent element RADIOACTIVE ISOTOPE = an isotope that gives off energy and decays into another isotope A breakthrough came with the discovery of radioacticity at the beginning of the 1900s. Scientists discovered that rocks could be timepieces -- literally. Many chemical elements in rock exist in a number of slightly different forms, known as isotopes. Certain isotopes are unstable and undergo a process of radioactive decay, slowly and steadily transforming, molecule by molecule, into a different isotope. This rate of decay is constant for a given isotope, and the time it takes for one-half of a particular isotope to decay is its radioactive half-life. For example, about 1.5 percent of a quantity of Uranium 238 will decay to lead every 100 million years. By measuring the ratio of lead to uranium in a rock sample, its age can be determined. years....
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This note was uploaded on 10/13/2008 for the course BIO 102 taught by Professor B during the Spring '08 term at University of California, Berkeley.
- Spring '08