Question

The fur colour distribution in rodent population is depicted in the graph. With the passage of time, the environment changes in such a way that light and dark spots are left with little vegetation.

Which of the following is true for the distribution of phenotypes according to natural selection?

• A. The mean will shift toward the right, and the center of the curve will be higher
• B. The mean will shift toward the left, and the center of the curve will be higher
• C. The mean will shift toward the right, and the center of the curve will be lower
• D. The mean will remain the same, and the center of the curve will be higher
• E. The mean will remain the same, and the center of the curve will be lower

Answer 1

The correct option is E The mean will remain the same, and the center of the curve will be lower

Natural selection is the process by which any favorable heritable traits become more common in successive generations while unfavorable heritable traits become less common. This acts on an organism's phenotype,which is further determined by an organism's genetic make-up and the environment where it lives. natural selection can occur with or without environmental effect and can either be directional, stabilizing, diversifying or kin selection. According to the graph in question, this is a case of stabilizing natural selection where it favors the intermediate states of continuous variation. Over time, the intermediate states become more common and each extreme variation will become less common or lost. Hence the mean will remain same but the center of the curve will be lower.