Natural Selection and Patterns of Evolution Worksheet

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Associate Level Material

Appendix F

Natural Selection and Patterns of Evolution Worksheet

Complete the worksheet writing 100- to 200-word short answers for each question. Format your references consistent with APA guidelines.

1. What is the direct evidence in support of the theory of natural selection? Include at least four examples. Paleontology shows us that organisms have changed gradually over time, as reflected in the fossil record. Biogeography shows us how new species only arise near very similar species. Similar species share a common time and place. Developmental biology shows us that an organism builds on ancestral features as it develops from a single cell. Genetics shows us that we can group species by similarity of genes.

2. Humans shape their environment in ways that other organisms cannot. Are humans subject to the same pressures of natural selection as other organisms? Why? Humans, just as all other organisms are subject to natural selection pressures. The fact is that over a period of time, unavoidable gene pool changes occur in all species. It is estimated that ever since humans branched away from chimpanzees, they have been experiencing 4.2 amino acid changing mutations on average per generation (Gould, S.J. 2002). Through a mechanism called genetic drift, gene frequencies change over a period of time, and it’s very occurrence is a phenomenon that cannot be denied. Random events cause an increase or decrease in a certain gene, occasionally resulting in gene fixation or extinction. Humans are subject to such accepted Biological phenomenon just as all other species. The ability of humans to impact their environment does not mean that they have a realistic sense of control over it, nor does it in any way prevent the occurrence of mutations in them, so the pressures of natural selection still apply to them in the varied environments that they live across the world.

3. Provide an example of convergent...
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