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)

Question

Responses

directional; the curve would shift to the left
directional; the curve would shift to the left

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 right
directional; the curve would shift to the right

disruptive; the curve would break into two peaks with a dip in the middle

Answer 1

The type of selection described in the scenario is directional selection, as the size of black bears shifts towards one end of the size spectrum during different environmental conditions (smaller sizes during warmer periods and larger sizes during ice ages).

As Earth moved out of an ice age and entered a warmer period, the graph of the distribution curve of black bear size would reflect this shift. Specifically, the curve would shift toward the left, indicating that smaller black bears became more prevalent.

Therefore, the correct response is:

directional; the curve would shift to the left.