XXXX - subsequently was lost in evolution is difficult....

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Jona Mata AP Biology – 3 rd period November 16, 2010 The Animal(s) Within Us Christiane Nüsslein-Volhard Life on Earth took many forms before the emergence of mammals and mankind. The forms evolved over time, adapting to new conditions and changing genetically and physically to become the fittest to survive in the changing environment. These genetic relationships to ancestral forms can be seen in taxonomy, in which animals are placed in phylum, classes, order, genera and species, that show the physical similarities of the group and also groups them under one common ancestor. These evolutionary relationships can also be seen in embryonic forms of animals, in which the presence of an amnion determines the grouping and relationships. Yet, in many cases, determining that the animal lacking a particular trait is more basic and that its ancestor preceded the one of the animal that has the trait or whether the trait had been present originally but
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Unformatted text preview: subsequently was lost in evolution is difficult. Thus, these uncertainties called for several criteria in the determination of evolutionary relationships. The most reliable criteria can be found through examination of molecular characteristics or, more specifically, the comparison of DNA homologous base pairs between organisms. The DNA comparisons show that a common ancestor of all organisms would be a bacteria-like cell, which had DNA for replication and a system that allowed metabolism. After time, multicellularity occurred with the rise of the eukaryotic cell as the Cambrian period allowed for growth. Genome research also indicates that, humans differ from chimps by only about one percent of the bases. Therefore, molecular biology could be successfully used to amount for evolutionary relationships....
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This note was uploaded on 12/01/2010 for the course BIOS 140 taught by Professor Webster during the Spring '08 term at DeVry Austin.

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