With respect to the genes controlling body size, the results of the experiment suggest that
a - VCE - SSCE Biology - Question 21 - 2003 - Paper 1
Question 21
With respect to the genes controlling body size, the results of the experiment suggest that
a. after 25 generations there was no genetic variation.
b. for the firs... show full transcript
Worked Solution & Example Answer:With respect to the genes controlling body size, the results of the experiment suggest that
a - VCE - SSCE Biology - Question 21 - 2003 - Paper 1
Step 1
a. after 25 generations there was no genetic variation.
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Answer
This statement is incorrect. The results of the experiment indicate that selection may have acted on the existing genetic variation but does not imply the absence of genetic variation.
Step 2
b. for the first 25 generations there was no genetic variation.
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Answer
This statement is also incorrect. Although the smallest flies were selected, this does not imply a lack of genetic variation; there could still be variation within the population allowing for that selection to occur.
Step 3
c. selection between generations 25 and 35 had a significant effect on average body size.
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This statement is correct. The reversal in selection, where larger flies were selected, likely led to an increase in the average body size over those generations, reflecting a significant effect.
Step 4
d. if selection for small body size continued after generation 25, average body size would continue to fall.
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This statement is plausible. Maintaining selection pressure for smaller body size would likely lead to a continued decrease in average body size, as the selection process favors smaller individuals.
