Biology 3466B Final: Final Exam Notes
Document Summary
Transitional fossils document the past existence of species displaying mixtures of traits typical of what are today distinct groups of organisms. Radiometric dating is a method of measuring the ration of parent isotope to daughter isotope in a rock sample since unstable isotopes emit particles at a constant clock-like rate. Age of rock = (# of half-lives that have elapsed)(# of years it takes for a half life to elapse) Potassium argon method half-life of potassium = 1. 3billion years. Rapid diversification and appearance of almost all animal phyla. Climate not well know, prob warming from cold, ice covered. Ice melts, ocean levels rise, oceans cover much of n. a. There is increasingly strong evidence that small-bodied bilaterally symmetric animals were present prior to the cambrian explosion. Compared to animals present earlier in the fossil records, the hallmarks of the cambrian fauna are: Most of the animal phyla living today make their first appearance in the fossil record during the cambrian.
