Evolution Lab Handout2_101L

Evolution Lab Handout2_101L - Laboratory 7 Evolution...

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Laboratory 7 Evolution Biology 101L 7-1 BIOLOGY 101L Lab 7: Evolution Objectives (1) Classification (2) Evolution I. Classification Humans classify almost everything, including each other. This habit can be quite useful. For example, when talking about a car someone might describe it as a 4-door sedan with a fuel injected V-8 engine. A knowledgeable listener who has not seen the car will still have a good idea of what it is like because of certain characteristics it shares with other familiar cars. Humans have been classifying plants and animals for a lot longer than they have been classifying cars, but the principle is much the same. In fact, one of the central problems in biology is the classification of organisms on the basis of shared characteristics. As an example, biologists classify all organisms with a backbone as "vertebrates." In this case the backbone is a characteristic that defines the group. If, in addition to a backbone, an organism has gills and fins it is a fish, a subcategory of the vertebrates. This fish can be further assigned to smaller and smaller categories down to the level of the species. The classification of organisms in this way aids the biologist by bringing order to what would otherwise be a bewildering diversity of species. (There are probably several million species - of which about one million have been named and classified.) The field devoted to the classification of organisms is called taxonomy [Gk. taxis, arrange, put in order + nomos, law]. The modern taxonomic system was devised by Carolus Linnaeus (1707-1778). It is a hierarchical system since organisms are grouped into ever more inclusive categories from species up to kingdom. Figure 1 illustrates how four species are classified using this taxonomic system. (Note that it is standard practice to underline or italicize the genus and species names.) Key terms Evolution: change in the gene pool of a population from generation to generation. Natural Selection: individuals possessing heritable advantageous traits will leave more offspring, perpetuating the advantageous trait and resulting in population evolution over time. Fitness: reproductive success. Adaptation: an alteration in the structure or function of an organism (or any of its parts) that results from natural selection and which increases an organism’s fitness.
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Laboratory 7 Evolution Biology 101L 7-2 According to this system, classification was simply a useful means of cataloging the diversity of life. II. Darwin This view of taxonomy changed dramatically when Charles Darwin published On The Origin of Species in 1859. In his book Darwin presented convincing evidence that life had evolved through the process of natural selection . The evidence gathered by Darwin, and thousands of other biologist since then, indicates that all organisms are descended from a common ancestor. In the almost unimaginable span of time
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This note was uploaded on 11/15/2010 for the course BIOL 101l taught by Professor Huddleston,m during the Fall '08 term at University of Hawaii, Manoa.

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Evolution Lab Handout2_101L - Laboratory 7 Evolution...

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