Natural Selection

Natural selection is a mechanism in evolutionary biology, whereby organisms with advantageous traits for their environment are more likely to survive and reproduce. This process actively contributes to the gradual transformation and diversification of species by favoring the propagation of beneficial adaptations within a population over time.

Peppered Moth (Before)

The peppered moth, Biston betularia is a classic example of evolution by natural selection. Before the industrial revolution, most peppered moths in England had light-colored wings that helped them blend in with lichen-covered tree bark.

Peppered Moth (After)

As pollution darkened the trees, darker-colored moths became better camouflaged and more likely to survive and reproduce. Over time, the frequency of the dark-colored moths increased while the light-colored moths decreased. This shift in characteristics demonstrates how natural selection can lead to changes in a species over time.