Final answer:
The largest response to selection in a population occurs in scenario 2, where heritability is 0.5 and the selection differential is 0.9, leading to the greatest product of these two factors.
Step-by-step explanation:
The scenario that will produce the largest response to selection within a population is scenario 2, where -H₂ (heritability) = 0.5 and S (selection differential) = 0.9. The response to selection (R) in a population is estimated using the formula R = -H₂ × S. Therefore, it is important to consider both heritability and the selection differential to predict the response to selection.
The term heritability (-H₂) refers to the proportion of phenotypic variation in a population that is due to genetic variation among individuals. Heritability can range from 0 to 1, with higher values indicating a greater contribution of genetics to the observed variation. On the other hand, the selection differential (S) represents the difference between the mean phenotype of the selected parents and the mean phenotype of the original population. It measures the strength of selection, with larger values indicating stronger selection pressure.
When considering the response to selection (R), the key is to look for the highest product of -H₂ and S, as the response is directly proportional to both these factors. In the provided scenarios, scenario 2 (-H₂ = 0.5; S = 0.9) yields the highest product (0.5 × 0.9 = 0.45), indicating that this scenario would lead to the largest response to selection. This means that when selection is strong (high S) and a significant portion of the variation is heritable (substantial -H₂), the population will experience a rapid change in the traits being selected for.