Exaptation

“A structure can acquire a second job unlike the one it originally performed.”

01 / PLAINLY

What it means, plainly

An exaptation is a trait that gains a new function after arising for another function or without an initial function.

02 / CONTEXT

A little more

Exaptation separates a trait's historical origin from its current use. An existing feature can be recruited for another task and later refined by selection, without its first appearance anticipating that destination.

03 / WHY IT MATTERS

Why it matters

It breaks stories in which every part seems designed from the outset for its modern role and restores the importance of history.

04 / EXAMPLE

A familiar example

Feathers probably provided insulation or signaling before contributing to flight and later being modified for that function.

05 / LIMIT

What it does not mean

It does not mean the trait is nonadaptive today; it says its origin and current function are not the same.

06 / NOTICE

Notice it in your day

Choose a tool repurposed for another job and use it as an analogy, then note where the biological comparison breaks down.

FINAL NOTE

The idea worth keeping

Ask separately how a structure arose and what it does now; never infer a complete history from present use.

QUESTIONS / 02

Questions people still have

Is exaptation merely a change of function?

It includes traits originating for another function and traits initially nonadaptive that later become useful.

Can selection later modify an exaptation?

Yes. Once recruited, a trait can be refined by selection for its new function across later generations.