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 left
directional; the curve would shift to the left

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

Answer 1

directional; the curve would shift to the left

As the climate warms, smaller bears are favored, so the mean body size shifts toward smaller values (a leftward shift in the distribution).