Biology 3466B Lecture : Evolution Notes
3 Feb 2012
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Animals living in shallow, marine environments are more likely to fossilize. Fossilization is more likely to happen to molluscs because they live in marine environments and they have hard shells. Describing macroevolution: paleontology there are many types of fossils and these fossils can be dated in two ways. Relative is the sequence in which organisms were present on earth. Absolute is how many mya the animal lived and can be determined using radiometric dating and looking at layering in rock strata. Transitional forms, which are links between animals, may be missing, and this can obscure patterns because not everything is going to fossilize. The fossil record should show evidence of transformations in progress. Transitional species should show a mix of features, including traits typical of ancestral populations and novel traits seen later in descendants. Transitional fossils document the past existence of species displaying mixtures of traits typical of what are today distinct groups of organisms.
