Scientists have worked out many examples of natural selection, one of the basic mechanisms of evolution.

Natural selection can produce impressive adaptations that help organisms survive and reproduce. A few examples are shown below.

Behavior can also be shaped by natural selection. Behaviors such as birds’ mating rituals, bees’ wiggle dance, and humans’ capacity to learn language have genetic components and are subject to natural selection. The male blue-footed booby, for example, exaggerates his foot movements, an adaptation that helps him attract a mate.

In some cases, we can directly observe natural selection occurring. Very convincing data show that the shape of finches’ beaks on the Galapagos Islands has tracked weather patterns: after droughts, the finch population has deeper, stronger beaks that let them eat tougher seeds.

In other cases, human activity has led to environmental changes that have caused populations to evolve through natural selection. A striking example is that of the peppered moth, which may have either light or dark coloration. During the Industrial Revolution, when air pollution darkened tree trunks, dark-colored forms were favored because they were better camouflaged and so became more common. When pollution was later reduced, light-colored forms rebounded and became more common. Natural selection triggered by human activity can often be observed and documented.