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ch22 1. The __________ __________ model assumes that evolution occurs in spurts, between which there are long periods of stasis with little evolutionary change. ________________________________________ 2. A _______ is a group of organisms that differs in one or more characteristics from other groups, and does not hybridize or intermate extensively if they occur together in nature. ________________________________________ 3. Recurrent isolation promotes _______. ________________________________________ 4. The phenomenon where one species diverges into many by occupying a series of different habitats within a region is called __________ __________. ________________________________________ 5. The process by which related species become more different in order to reduce competition is called ___________ __________. ________________________________________ 6. The model that assumes that evolution proceeds with slow successive change in a given evolutionary line is referred to as A. successive descent model. B. punctuated equilibrium. C. gradualism. D. the allopatric model. E. the sympatric model. 7. The type of speciation that geographically isolates populations and results in the divergence of distinct species is called ____________ speciation. A. gradual B. sympatric C. allopatric D. sexual E. adaptive 8. A type of isolating mechanism that leads to reproductive isolation by preventing the formation of hybrid zygotes is called _____________ isolating mechanism. A. hybridization B. postzygotic C. prezygotic D. adaptive E. differential 9. A type of isolating mechanism that leads to reproductive isolation after a hybrid zygote has formed is called _____________ isolating mechanism. A. hybridization B. postzygotic C. prezygotic D. adaptive E. differential 10. Which one of the following is not an example of a reproductive isolating mechanism? A. sympatric isolation B. behavioral isolation C. ecological isolation D. mechanical isolation E. temporal isolation 11. The basic unit of evolution and taxonomy is the A. ecosystem. B. population. C. species. D. community. E. niche. 12. The distinctive role of a species in nature is its A. fitness. B. adaptation. C. habitat. D. niche. E. life cycle. 13. Two groups of organisms that differ from one another in one or more characteristics and do not hybridize extensively if they occur together in nature are considered to be different A. races. B. species. C. kingdoms. D. hybrids. E. cohabitants. 14. The model proposed by Eldredge and Gould for the formation of species is called the ___________ model. A. gradualism B. punctuated equilibrium C. adaptation D. natural selection E. common descent 15. Which of the following statements describe the assumptions of the gradualism model? ... View Full Document

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