AP Biology Notes - Ch. 25 & 26

AP Biology Notes - Ch. 25 & 26 - Text Analysis...

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Text Analysis Questions Chapter 25 1. Distinguish between phylogeny and systematic. List ways systematic has added to phylogey. Phylogeny is the eviolutionary history of a species or a group of related species. Systematics is the study of biological diversity in an evolutionary context. Phylogeny is the subgroup and systematics is a larger group. For both phylogeny and systematics, fossil records are significant for examination. 2. Explain why the fossil record is incomplete. For a fossil to be formed and to be discovered, the situations need to coincide, which has a low probability. The organism has to die in a suitable condition and preserved until it is discovered. Also, not all organisms become fossilized. 3. Explain the problems that convergent evolution causes for phylogeny. Give an example. Convergent evolution creates problems for paleontologists using evolutionary patterns in taxonomy, or the categorization and classification of various organisms based on relatedness. It often leads to incorrect relationships and false evolutionary predictions. 4. Describe the importance of molecular homologies and how they are evaluated. Describe three types of DNA which is evaluated and how each provides a different picture for systematic. A species' evolutionary history leaves signs in its DNA and the proteins that DNA codes for. Two species that share a DNA base sequence (and also the specific protein coded for) probably have a common ancestor. Usually the DNA base sequence will be slightly different between the two, as each species will have accumulated different mutations once they separated. The number of mutations can be used to indicate how closely related the species are. It can also be used as an indication of how long ago they became separate species. In fact a common genetic code is shared by all species. This shows that natural selection reuses genes and structures that have worked well in the past.All living organisms have their instructions for reproducing and operating encoded in a chemical language using four bases, adenine (A), cytosine (C), guanine (G) and thymine (T). Combinations of the bases specify which amino acids the cell uses in making proteins for use in cell functions. The fact that every living species carries the same genetic code indicates a common single ancestor at some point in the distant past. 5. Describe the role of systematic with taxonomy. Systematics uses taxonomy as a primary tool in understanding organisms, as nothing about an organism's relationships with other living things can be understood without it first being properly studied and described in sufficient detail to identify and classify it correctly. Scientific classifications are aids in recording and reporting information to other scientists and to laymen. The systematist, a scientist who specializes in systematics, must, therefore, be able to use existing classification systems, or at least know them well enough to skillfully justify not using them.
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This note was uploaded on 10/01/2011 for the course BIOLOGY 1510 taught by Professor --- during the Spring '11 term at Georgia State University, Atlanta.

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AP Biology Notes - Ch. 25 & 26 - Text Analysis...

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