Question

Paleontologists observed changes in the sizes of black bears as their environment changed. During warmer periods between ice ages, most black bears were small. During ice ages, most black bears were large. Which type of selection is this, and how would a graph of the distribution curve of black bear size change as Earth moved out of an ice age?(1 point) Responses disruptive; the curve would break into two peaks with a dip in the middle disruptive; the curve would break into two peaks with a dip in the middle directional; the curve would shift to the right directional; the curve would shift to the right stabilizing; the curve would become taller in the middle and shorter on each side stabilizing; the curve would become taller in the middle and shorter on each side directional; the curve would shift to the left

Answer 1

The type of selection described in your scenario is disruptive selection. This is because there are two distinct size categories (small and large black bears) during different environmental conditions, which leads to the potential for two peaks in the distribution curve.

As the Earth moves out of an ice age and into a warmer period, the graph of the distribution curve of black bear size would likely show disruptive selection where the curve would break into two peaks with a dip in the middle, reflecting the prevalence of smaller and larger bears while fewer bears fall into the intermediate size category.

Therefore, the appropriate response would be: disruptive; the curve would break into two peaks with a dip in the middle.