Guppies living in a stream have a variety of spot patterns, some of which provide good camouflage against the stones in the streambed and others of which make them stand out against the background, allowing potential mates to see them more easily. If a predator that hunted by sight were introduced to the stream, what would be the most likely long-term consequence for the guppy population?

Question

anonymous · Answer

a. The guppy population would devise a mutation that allowed the camouflaged guppies to find mates by scent or sound.
b. The guppy population would die out since none of the guppies would be able to find mates.
c. The number of camouflaged guppies in the population would increase while the number of successful matings decreased.
d. The number of guppies in the population would decline, although most of the remaining ones would be uncamouflaged.

anonymous · Answer

i think its b

blues · Answer

Why B?

I think it's C because the total number of guppies would decrease and the total number of matings would decrease - but the number of camouflaged guppies would increase because the predator can't see them, can't eat them and they and their offspring (presuming that speckledness is a genetically inherited trait) would survive better than the visible guppies...

anonymous · Answer

that makes sense, but how would the population increase if no one is mating?

blues · Answer

The speckled guppies are mating. The predator can't see them, so there are mates for them aplenty.

anonymous · Answer

oh i get it tahnks

blues · Answer

Cool.