Features are like feathers: you never know how they will be used

We now know that many dinosaurs had feathers. However, this doesn’t mean that all feathered dinosaurs could fly: it is believed that feathers first evolved for insulation rather than flight, and developed over millions more years to provide lift as well as warmth.

Feathers are an example of exaptation: a term proposed by Stephen Jay Gould and Eilsabeth Vrba in 1982, to describe the phenomenon of something that evolved for one purpose, and has been adapted by evolution to serve another purpose. Other examples include the development of two of the bones that formed part of the reptilian jaw to become the malleus and incus, essential parts of the mammalian ear: we hear with bones that reptiles use to eat.

Exaptation is a useful concept in technology too, and we do not have to wait millions of years to see it in action: human ingenuity acts faster than evolution. For example, take the powerful computing devices we carry in our pockets and call ‘mobile phones’.