[DSRP Evidence](https://dsrpevidence.org/)

# Exaptation—a Missing Term in the Science of Form

## Details

**Authors** Gould, Stephen Jay and Vrba, Elisabeth S.

**Year** 1982

**Publisher** Paleobiology

**Kind of work** article

**Discipline** Evolutionary Biology

**Secondary disciplines** Philosophy

**Applied** false

[Read it at the publisher](https://doi.org/10.1017/s0094837300004310) 
10.1017/s0094837300004310

## In authors' words

### What they set out to do (purpose)

To resolve the confusion in the term adaptation, which has been defined both by a feature's historical origin and by its current usefulness.

### Who or what was studied (sample)

Examples from the literature, including feathers and flight, bone, lysozyme and lactation, spotted hyena genitalia, and repetitive DNA.

### How they did it (methods)

Conceptual and terminological analysis with illustrative cases.

### What they found (results)

The authors restrict adaptation to features built by selection for their current role, and name features that are useful now but were co-opted from other origins exaptations; the shared state of fitness is aptation. Adaptations have functions; exaptations have effects. Nonaptations (by-products, correlated traits, selfish DNA) provide the raw material for later exaptations.

## Commentary

### In short

Gould and Vrba separate traits shaped by selection for their present use from traits that were repurposed, and give the second kind a name.

### Response

The central move is a distinction between historical origin and current utility (D), tied to a causal relationship between selection and the trait (R). Caveats: the paper's treatment of levels is implicit and was not developed into a part-whole framework, so S is not ticked; it is a terminological proposal rather than an empirical test.

**Patterns it shows** D, R

Shows the structure is there

**Added** 2026-10-15

**How to cite this** Gould, Stephen Jay and Vrba, Elisabeth S. (1982). Exaptation—a Missing Term in the Science of Form. Paleobiology.