A measure of biological fitness expressed as the total number of gene copies transmitted to the subsequent generation or the total number of surviving offspring that an individual produces during its lifetime.
In biology, Darwinian fitness or simply fitness of a biological trait describes how successful an organism has been at passing on its genes. The more likely that an individual is able to survive and live longer to reproduce, the higher is the fitness of that individual.
There are two ways through which fitness can be measured:
Absolute fitness (wabs) can be expressed as the total number of individuals, of phenotypes, or of genotypes. It can also be calculated as the product of the proportion survival and the average fecundity.