An organism's phenotype is the sum of its observable characteristics from it's anatomy to its behavior. It is the physical expression of the organism's genes or "genotype". Early study of biological species focused on an organism's phenotype to characterize it and group it with organisms with a similar phenotype. However, in modern biology, its importance has been lessened by the focus on an organism's DNA to establish its relationships with other organisms.
Most species exhibit multiple phenotypes of at least one characteristic, but these phenotypes are all limited, such as human skin color and hair color.
Phenotypes exclude any characteristic that cannot be traced to a genetic cause, such as those caused by injuries.