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Unformatted text preview: e organisms living on these islands are descendants of species that have emigrated there, primarily from South America. In studying the finch populations, researchers have identified fourteen species, none of which are found on the mainland. 182. The initial colonizing population of finches most likely exhibited which of the following? (A) Hybridization with bird species already existing on the islands (B) High rates of interbreeding with mainland populations (C) Increased rates of mutation to fill habitats (D) A novel behavior not seen in mainland populations (E) A smaller gene pool than that of the mainland populations 183. As opposed to the mainland, on the islands the initial colonists (finches) had the opportunity to evolve in new directions primarily because there (A) (B) (C) (D) (E) was an absence of interspecific competition was mixing of the gene pool was a higher mutation rate was higher predation pressure were higher levels of inbreeding 184. Initially, one species of finch may have settled on two different islands, maintained this separation over hundreds of years, and eventually followed divergent adaptive pathways. If these now two separate species should migrate onto a new island, they could maintain their individual species identities on this island in all the following ways EXCEPT if one species (A) hybridizes successfully with the other species (B) lives in the forests and the other in the scrubland (C) carries out different stages of its life cycle at different times than the other species (D) fails to produce viable young after mating with the other species (E) is not attracted to the other species for mating 185. Although the initial finch species on the islands may have all been seed eaters, which of the following processes minimized competition as the population expanded? (A) Selection for niche diversification (B) Development of more efficient attack behavior (C) Further emigration when carrying capacity was reached (D) Genetic drift (E) Postzygotic mating factors GO ON TO THE NEXT PAGE. Unauthorized copying or reuse of any part of this page is illegal. 56 Questions 186-188 Lymphocytes extracted from the rat kangaroo, Potorous tridactylus, were grown in culture for karyotype analysis. To obtain chromosome spreads, such as that illustrated below, lymphocytes were incubated in the antimitotic drug colchicine for 30 minutes before fixation and staining. The chromosomes depicted below are representative of the karyotype found in all of the cells of the culture. 186. Which of the following correctly describes the chromosome number in this rat kangaroo cell? (A) (B) (C) (D) (E) The haploid chromosome number is 12. The haploid chromosome number is 24. The diploid chromosome number is 12. The diploid chromosome number is 24. The triploid chromosome number is 24. 188. During S phase, DNA synthesis originates at specific sequences in the chromosomal DNA. How many sites for initiation of DNA synthesis would be expected among the chromosomes within the rat kangaroo karyotype during S phase? (A) (B) (C) (D)...
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This document was uploaded on 03/16/2014 for the course BIO 1434 at UT Arlington.
- Spring '14