PCRQ R Week 5_ 24W-LIFESCI-7B-LEC-1 Genetics, Evolution, and Ecology

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May 15, 2024

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3/28/24, 12:31 PM PCRQ R Week 5: 24W-LIFESCI-7B-LEC-1 Genetics, Evolution, and Ecology https://bruinlearn.ucla.edu/courses/178453/quizzes/1003133?module_item_id=6462708 1/4 PCRQ R Week 5 Due Feb 8 at 8am Points 2 Questions 8 Available until Mar 22 at 11:59pm Time Limit None Allowed Attempts 2 Instructions This quiz was locked Mar 22 at 11:59pm. Score for this attempt: 2 out of 2 Submitted Feb 8 at 2:22am This attempt took 5 minutes. Question 1 0.25 / 0.25 pts Correct! They arose allopatrically because they diverged when separated into two islands. They arose sympatrically because they are on the same peninsula. Question 2 0.25 / 0.25 pts This quiz covers reading from Chapter 21. A researcher finds two closely related species of rodent, A and B, living sympatrically on a coastal peninsula. Geological analysis suggests that higher sea levels in the past have occasionally cut off parts of the peninsula, with the lower parts of the peninsula being under water and higher parts becoming separate islands. Did species A and B arise sympatrically or allopatrically? Disruptive selection is a key component of sympatric speciation because it acts against the homogenizing effect of gene flow between the diverging populations. Imagine a case in which a bird population is undergoing disruptive selection on bill size in response to the availability of seeds to eat.
3/28/24, 12:31 PM PCRQ R Week 5: 24W-LIFESCI-7B-LEC-1 Genetics, Evolution, and Ecology https://bruinlearn.ucla.edu/courses/178453/quizzes/1003133?module_item_id=6462708 2/4 Correct! medium-sized bills. large bills. small bills large bills and birds with small bills. medium bills and birds with large bills. Question 3 0.25 / 0.25 pts Correct! gene flow between populations prevents genetic divergence in sympatry. gene flow between diverging populations is strong in allopatry. related species are always found in allopatry rather than in sympatry. vicariance events are common. disruptive selection between forms of traits in sympatric populations is always very strong. Question 4 0.25 / 0.25 pts The birds' environment contains large and small seeds, as no medium seeds are available. Assume that a bird's ability to eat a seed is a direct function of its bill size (large bills are good for large seeds, and so on). You would expect to see a decrease in birds with __________________ . Most speciation is allopatric because: An ancestral population is split into two different gr oups, and they no longer interbreed after separation. Consider the graphs. Whic h graph correctly illustrates the number of genetic differences that would be seen between the two populations?
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