Difference Between Acclimation and Adaptation

Acclimation vs Adaptation

Living systems are homeostatic as they tend to adjust to unfavorable environmental conditions by minimizing strain and maintaining equilibrium. This adjustment is crucial for living organisms to survive on earth. Some of these adjustments are passed to next generations by organisms to increase survival change of their offspring. Some of these adjustments are only short term and do not pass to the next generation. Therefore, depending on their time scale and heredity, homeostatic modifications can be classified as acclimation and adaptations. Adaptations involve genetic modification and acclimation does not; so that only adaptations are passed to next generations.


Acclimations are metabolic adjustments of an individual, which may or may not require transcription of genes. These adjustments may cause significant phenotypic morphological and physiological changes in an individual, but they are not heritable. Hence, acclimations cannot be seen in population level. Unlike the adaptations, acclimations are always short term. They improve the fitness under new environmental condition and may be reversible. For example, drought hardening of plants due to moderate water stress and cold hardening of plants due to gradually decreasing temperature are two acclimations shown by plants.


Adaptation is a heritable modification in structure or function that leads to increase the probability of survival of an organism. Since it is heritable and act on allelic variation, adaptations can be seen within the population level and organisms tend to pass these favorable genes to their offspring. Unlike the acclimation, adaptation results in irreversible changes to genome. For example, thick cuticle, hairiness, and responsive stomata are considered as adaptations of plants grow in dry habitats.

What is the difference between Acclimation and Adaptation?

• In adaptation, population level is considered while, in acclimation, individual level is considered.

• Acclimation is due to the local environmental conditions acting on genetically- determined physiological responsiveness. In contrast, adaptation is caused by natural selection acting on allelic variations.

• Heritability of adaptation is genotypic, whereas acclimation is non- heritable.

• Acclimation is reversible, whereas adaptation is irreversible.

• In adaptation, response of homeostasis to perturbation is mostly plastic whereas, in acclimation, it is mostly elastic.

• Adaptations are long-term, whereas acclimations are short-term.

• Adaptations are strategic in nature while acclimations are tactical in nature.