Exaptation is a term used to refer to the process of evolution that occurs when a trait or characteristic is used for a purpose that is different from the one it was originally adapted for (Dawkins, 2004). This concept was first introduced by Stephen Jay Gould and Elizabeth Vrba in 1982 as a way to explain why certain features of organisms have remained unchanged over time, even though their original purpose has been lost or changed (Gould & Vrba, 1982). Exaptation is an important concept in evolutionary biology, as it explains why some traits are conserved even when they may not have an obvious benefit in the current environment.
Exaptation is based on the idea that certain traits are conserved because they were once adaptive, even if they are no longer used in the same way. For example, feathers were initially adapted for insulation, but later came to be used for flight (Gould & Vrba, 1982). Similarly, the wings of birds may have originally been used for balance, but later evolved for flight (Dawkins, 2004). This idea suggests that some features of organisms may be “exapted”—or used for purposes that are different from the ones they were originally adapted for—over time.
Exaptation has been used to explain the evolution of a variety of traits and characteristics, such as the development of eyes in certain animals (Gould & Vrba, 1982). In this case, the eyes may have initially been adapted for sensing light or other environmental stimuli, but later evolved for vision. Similarly, the wings of some insects may have initially been adapted for gliding, but later evolved for flight (Gould & Vrba, 1982).
Exaptation is also believed to have played a role in the evolution of human behavior. For example, the ability to use language may have originally been used for communication between group members, but later evolved to include more complex forms of communication such as rhetoric and storytelling (Dawkins, 2004). Similarly, the use of tools may have initially been used for providing food and shelter, but later evolved for more complex purposes, such as the construction of weapons or tools for scientific inquiry (Gould & Vrba, 1982).
Exaptation is an important concept in evolutionary biology, as it explains why some traits are conserved even when they may not have an obvious benefit in the current environment. This concept suggests that some features of organisms may be “exapted”—or used for purposes that are different from the ones they were originally adapted for—over time. By understanding how exaptation works, scientists can better understand the evolution of various characteristics and traits in organisms.
References
Dawkins, R. (2004). The ancestor’s tale: A pilgrimage to the dawn of life. New York, NY: Houghton Mifflin Company.
Gould, S. J., & Vrba, E. S. (1982). Exaptation—A missing term in the science of form. Paleobiology, 8(1), 4-15.