In a very large population, a quantitative trait has the distribution pattern shown in Figure 21.3.
Figure 21.3
-If the curve in Figure 21.3 shifts to the left or to the right, there is no gene flow, and the population size consequently increases over successive generations. Which of the following is (are) probably occurring? 1. immigration or emigration
2) directional selection
3) adaptation
4) genetic drift
5) disruptive selection

Question

In a very large population, a quantitative trait has the distribution pattern shown in Figure 21.3.
  Figure 21.3
-If the curve in Figure 21.3 shifts to the left or to the right, there is no gene flow, and the population size consequently increases over successive generations. Which of the following is (are) probably occurring? 1. immigration or emigration
2) directional selection
3) adaptation
4) genetic drift
5) disruptive selection

Quizplus · Accepted Answer

Directional selection and adaptation can cause a shift in the curve without gene flow, leading to changes in population size over generations.

In a Very Large Population, a Quantitative Trait Has the Distribution