Question

Sea gulls prey on snails on the rocky sea coast. The snails vary in color from solid brown to brown and tan striped. The birds suck the soft snail bodies out of the shells and leave the shells behind on the rocks. Scientists picked up 500 empty shells and found that 400 of the shells were solid brown and only 100 were striped. Over the years, what would you expect to happen to the snail population?

Answer 1

On USA Test Prep its C.

Answer 2

Over the years, the population of solid brown snails would decrease or extinct whereas the population of striped snails may increase comparatively.

It can be explained with the natural selection.

Striped snails must have some survival advantage over the solid color snails as they account for only 20% of the snails hunted by Seagulls.

It might be hard for the Seagulls to spot striped snails as compared to the solid snails.

Consequently, striped snails would survive and reproduce easily as compared to the solid brown snails.

Thus, the population of strip color snails would increase and that of solid brown snails would decrease.