Question

The weight of a newborn varies by species and ranges from 2 to 5 kg. 97 percent of newborns weighing 3 to 3.3 kg survive, but 99 percent of infants weighing 2 to 2.5 kg or 4.5 to 5 kg die. What kind of selection process is being used?

• A. Directional selection
• B. Stabilizing selection
• C. Disruptive selection
• D. Cyclical selection

Answer 1

The correct option is B

Stabilizing selection

The correct option is option B.

Explanation for the correct option:

1. Both the extreme ranges, minimum and the maximum are dying and the mid-range ie 3 to 3.3 are the ones that survive.
2. Intermediate ones are the ones that are selected and are surviving.

Explanation for the incorrect options:

Option A

1. When individuals with attributes on one side of the population's mean survive or reproduce more than the others, this is known as directional selection.

Option C

1. When both extremes are selected and the middle values die, this is known as disruptive selection.
2. Here opposite of disruptive selection is being observed.

Option D

1. It occurs due to environmental fluctuations.
2. When individuals of one side are favored followed by a selection of individuals on the other side this selection occurs.
3. Here this is not observed hence, it is incorrect.

Final answer: Therefore, the selection process being used here is stabilizing selection.