NAME 7. (12pts) You have been studying a population of deer mice along a creek b
ID: 3478939 • Letter: N
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NAME 7. (12pts) You have been studying a population of deer mice along a creek bed for three years now. Unfortunately, last winter it rained for 17 weeks straight and the creck was badly After the flood you set traps for your population of mice but only catch 22 of the 44 m were in your population just prior to the calculate that the average body size (total len was 15 cm, while the average body size of the mice that survived was 10 cm ice that flood. You were able to go back in your records and gth from nose to tail) of the mice prior to the flood A. What is the selection differential on body size as a result of the flood? B. Is this stabilizing, disruptive, or directional selection? C. You look back in your data and found measurements of body size for 10 pairs of parents and their offspring. You plot a regression of the average body size of offspring (y axis) on the average body size of their parents (x axis). The equation for the best fit line on this was is: y- 0.85x + b. What is the estimated heritability of body size? D. The mice that survived the flood have now reproduced. When their offspring reach adult size, what do you predict the average body size of this generation of mice will be? E. It turns out that the mice have also evolved longer legs. Give two explanations for this result (I sentence each):Explanation / Answer
A. Selection differential = 10 - 15 = -5 cm
B. Since the selection is associated with an abrupt change in environment and a particular spectrum of phenotype (shorter mice) has been selected, it is directional selection.
C. The regression of the average value of the offspring on the average value of the parent is the heritability.
Given that y = 0.85x + b.
Hence, estimated heritability = 0.85
D. Response to selection = heritability × selection differential = -5 × 0.85 = -4.25 cm
Average body size of progeny = 15 + -4.25 = 10.75 cm
E. Longer legs may have been selected because:
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