Certain variations allow an individual to survive and reproduce more often than
others, so over time more individuals in the population will have the successful trait.
* adaptation - adjustment to environmental conditions: such as
a
: adjustment of a sense organ to the intensity or quality of stimulation
b
: modification of an organism or its parts that makes it more fit for existence under the conditions of its environment : a heritable physical or behavioral trait that serves a specific function and improves an organism's fitness or survival