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AP BIOLOGY: Chapter Twenty-Two Review Answers 
1. Species refers to groups that differ in one or more characteristics and do not naturally intergrade to any great extent. 2. A niche is the distinctive role an organism plays in nature, habitat, behavior, feeding, etc. Only one species can occupy any given niche at a time. 3. They adapt according to environmental demands and changes. 4. Forces that differ greatly produce rapid divergence. If forces are similar, there is slow divergence. 5. If populations are reproductively isolated, there may be subtle selective forces that cause one population to diverge more strongly from another, despite geographic proximity. 6. Geographical, ecological, temporal, behavioral, and mechanical isolations exist to the formation of hybrids. Prezygotic mechanisms prevent gamete fusion; postzygotic mechanisms involve embryo developmental failure or abnormalities. 7. Species hybrids are at a fitness disadvantage when the hybrids are sterile, are nearly sterile, or are less well-adapted to survive in the environment. The disadvantage to the hybrid is that they often do not survive, and if they do, they do not pass their genes on to following generations. 8. Adaptive radiation refers to groups of closely related species which evolved from a common ancestor. An example would be Darwin's finches or Hawaiian Drosophila. Isolated discontinuous habitats (such as islands or lakes) encourage adaptive radiation, because they are subject to a unique combination of selective pressures in a small place, often leading to rapid divergence among small subpopulations, leading to the development of new species. 9. Behavioral isolation maintains the integrity of the species clusters of Drosophila in the Hawaiian Islands. 10. Sexual selection is differential reproduction resulting from variable success in obtaining mates due to combat or courtship. Natural selection is the natural predominance of certain phenotypes over others in nature; the more favorable survive to leave more offspring and therefore perhaps alter gene frequencies. 11. Varied habitats in close proximity to one another and rapid changes in climate foster rapid evolution. 12. Polyploidy is an amount of genetic material greater than 2N. Parthenogenesis is asexual reproduction wherein the egg develops directly into the embryo or wherein somatic cells fuse to produce the embryo. | ||||||||||||
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