Dictionary > Adaptation


adaptation definition

n., ˌædæpˈteɪʃən
The process or the state of adjusting or changing to become more suited to an environment; the trait as a result of the process

Adaptation Definition

In biology and ecology, adaptation refers to the process of adjusting in behavior, physiology, or structure to become more suited to an environment. It may also be defined as the state reached by the biological population undergoing adjustments or changes. It may also pertain to the trait that made the species a better fit to the environment. The trait is referred to as the adaptive trait.


The term adaptation came from the Latin “adaptō”, meaning “I fit” or “I adjust to”. It is a common word in ecology and evolutionary biology. The organism tends to undergo changes to become more suited or fit to its environment. Adaptation differs from acclimatization. Both terms are about changes. However, acclimatization is the physiological adjustment to the new conditions but it does not entail increasing species diversity as adaptation does. For a trait to be considered as an adaptation, it has to be heritable, functional, and increases fitness. (Ref. 1)

According to Charles Darwin’s theory of evolution by natural selection, the organisms adapt to their environment so that they could persist and pass their genes onto the next generation. In the ecosystem, several species co-adapt, and in so doing they also co-evolve. Take for instance the symbionts in a lichen association. The algal and fungal components tend to co-evolve together as the absence of one implicates death. The dependence on each other’s existence means they have to adapt together, survive together.

Adaptations are essential to the species’ survival. The adaptive traits that the species will acquire through time may be structural (i.e. physical adaptive traits), behavioral (e.g. vocalizations, courtship rituals, nesting, and mating), or physiological (e.g. developing resistance to diseases or to toxic chemicals). (Ref. 1, 2)

Other Definitions

In neurology, adaptation refers to the decline in the frequency of firing of a neuron. In ophthalmology, it is the ability of the eye to adjust to various light intensities by regulating the pupil of the quantity of light entering the eye through the pupil.


  1. Defining adaptation. (2020). Berkeley.Edu. https://evolution.berkeley.edu/evolibrary/article/0_0_0/misconcep_06
  2. Adaptation. (2020). Berkeley.Edu. https://evolution.berkeley.edu/evolibrary/article/evo_31

Further Reading

©BiologyOnline. Content provided and moderated by BiologyOnline Editors.