BIOL 1F90 Lecture Notes - Lecture 3: Genetic Drift, Hybrid Zone, Habitat
21 Mar 2018
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Document Summary
Macro-: large, can be seen with naked eye. Zygote = diploid cell created by fertilization. Compare and contrast prezygotic and postzygotic isolating mechanisms. Outline two different mechanisms of sympatric speciation. Compare and contrast the concepts of gradualism and punctuated equilibrium. Describe how the spatial expression of genes, such as bmp4 and gremlin, affects pattern formation. Species: a group of organisms that maintains a distinctive set of attributes in nature. A species is a group of individuals whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring but cannot successfully interbreed with members of other species. Reproductive isolation prevents breeding with other species. Consequence of genetic changes as a species adapts to its environment. Prezygotic barriers: prevent formation of zygote. Postzygotic barriers: block development of viable, fertile individuals. Recall: zygote is the diploid cell arising after fertilization. Less common in nature because they are more costly in terms of energy and resources used.
