ADAPTATION

Adaptation occurs when a change in a phenotype increases an animal’s
chance of successful reproduction. It is likely to be expressed
when an organism encounters a new environment and
may result in the evolution of multiple new groups if an environment
can be exploited in different ways. No terms in evolution
have been more laden with confusion than adaptation and fitness
or adaptedness. Adaptation is sometimes used to refer to a process
of change in evolution. That use of the term is probably less
confusing than when it is used to describe the result of the process
of change. In this text, adaptations are defined as characteristics
that increase the potential of an organism or species to successfully
reproduce in a specified environment. In a similar fashion,

adaptedness or fitness is a measure of the capacity for successful reproduction
in a given environment.
Not every characteristic is an adaptation to some kind of environmental
situation. Some have erroneously concluded that if a
structure is now performing a specific function, it must have arisen
for that purpose and is, therefore, an adaptation. An extreme extension
of this incorrect view is that evolutionary adaptations lead
to perfection.