Chapter 17

28. The biological species concept relies mainly on ___________ to define a species. A. reproductive isolation B. morphological differences C. the presence of analogous traits D. comparative biochemical analysis

A

33 Isolating mechanisms that prevent reproductive attempts or make it unlikely that reproductive attempts will be successful are referred to as A. prezygotic reproductive isolating mechanisms. B. a lack of F2 fitness. C. postzygotic isolating mechanisms. D. Two of these are correct. E. None of the above.

A

39. A cross between a male horse and a female donkey produces a mule. Mules are an example of A. hybrid infertility. B. temporal isolation. C. gametic isolation. D. zygote mortality.

A

43. When members of a population are separated by a geographical barrier, so that no gene flow can occur between them, their gene pools can become so dissimilar that they become different species. The formation of species in this manner is called: ​(A) allopatric speciation, (B) sympatric speciation, (C) microevolution.

A

24. A major advantage of the evolutionary species concept is that it A. relies primarily on reproductive isolation to identify species. B. applies to both sexually and asexually reproducing species. C. uses morphological traits to distinguish species. D. is the same as the classic biological species concept.

B

35. Two species of the garter snake in the genus Thamnophis are found in the same geographic region. These species are not likely to meet and attempt to reproduce because one lives mainly in the water, while the other species spends most of its time on land. This is known as A. behavioral isolation. B. habitat isolation. C. temporal isolation. D. zygote mortality.

B

21. The evolutionary species concept involves the identification of certain structural traits, called _______, to distinguish one species from another. A. analogous traits B. homologous traits C. diagnostic traits D. convergent traits

C

32. A _____ is the first cell that results when an egg is fertilized by a sperm. A. spermatogonium B. gastrula C. zygote D. blastula

C

34. ________ prevent hybrid offspring from developing or if the hybrid is born, it is infertile. A. Prezygotic reproductive isolating mechanisms B. Temporal isolation mechanisms C. Postzygotic isolating mechanisms D. Two of these are correct. E. None of the above.

C

40. Norway rats (Rattus norvegicus) and roof rats (Rattus rattus) are different species. Occasionally, mating occurs if the two species are kept together in captivity. The resulting pregnancies are not successful and the embryos die. This is an example of A. mechanical isolation. B. hybrid sterility. C. zygote mortality. D. lack of F2 fitness.

C

23. All of the following statements concerning the evolutionary species concept are true EXCEPT A. an abrupt change in the diagnostic traits of fossils is indicative of the evolution of a new species. B. fossils are considered to be members of the same species if they possess the same diagnostic traits C. certain structural traits, called diagnostic traits, are used to distinguish one species from another. D. members of a species may actually have quite dissimilar evolutionary pathways.

D

29. The biological species concept is limited, and may not be applied to A. asexually reproducing organisms. B. organisms known only in the fossil record. C. species that could possibly interbreed if they lived near one another. D. All of the above.

D

31. Reproductive isolation A. means there is no gene flow between two groups of organisms (species). B. is necessary for species to remain separate. C. is maintained by certain prezygotic and postzygotic barriers. D. All of the choices are correct. E. None of the choices are correct.

E

42. Which of the following are examples of pre-zygotic isolating mechanisms? ​(A) behavioral, (B) hybrid sterility, (C) zygote inviability, (D) temporal isolation, (E) both A and D.

E