Citation:
Vestigial structures are anatomical features or behaviors that no longer seem to have a purpose in the current form of an organism. These often functioned in a way that was important for the organism's ancestors.
The process by which different kinds of living organisms developed and diversified from earlier forms during the history of Earth.
The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
A change or the process of change by which an organism or species becomes better suited to its environment.