Blackwell Publishing

The units of selection - Adaptation benefits . . . what exactly?


In this tutorial we will consider the ways in which adaptations can effect different levels of organisation.

Of course, there is no doubt that natural selection has produced many adaptations to benefit organisms. Most of the adaptations described in these tutorials are all adaptations that benefit the individual organism. These include

• the woodpecker's beak
• the color patterns of Biston betularia
• the mimicry of Papilio butterflies
• the camouflage of stick insects (pictured opposite)

It can hardly be doubted, therefore, that organismal adaptations exist, and natural selection can favor them. However, things are less clear cut when we consider other levels of organization.

W.D. Hamilton discusses the problem of the unit of selection.

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