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Often one or more changes may occur abruptly in some attributes of a group of animals, with the aid of which the group may get adapted to a changed environment. Such change may not be beneficial under the existing conditions. Such adaptation is known as Pre-adaptation or Prospective adaptation (Simpson, 1958).
On the other hand, the [...]

Adaptation is the modification or change in the structural, functional and behavioural attributes of an organism for better survival and to cope with existing environmental conditions.
Adaptations allow the animal to suit to the environment for better survival in the struggle for existence. It allows the animal to proceed through the evolutionary pathway.