Why Natural Selection Has Limits

Natural selection has limits, even when a trait would seem helpful. Organisms that fit their environment better are more likely to survive and reproduce. But evolution does not always produce perfectly adapted organisms.

One limit is that natural selection can only work with genetic variation tha...

Natural selection can produce striking adaptations that closely fit organisms to their environments, such as camouflage that protects butterflies from predatory birds.

However, natural selection does not always lead to ideal adaptations. Several factors constrain the outcomes of natural selection and prevent organisms from achieving...