Fitness is defi ned by an organism’s reproductive success relative to other members of its population. This success is determined by how long it survives, how often it mates, and how many off spring...

Fitness is defi ned by an organism’s reproductive success relative to other members of its population. This success is determined by how long it survives, how often it mates, and how many off spring it produces per mating. Relative fi tness assigns numerical values to diff erent phenotypes relative to the most fit phenotype.

■ Is one of these factors always the most important in determining reproductive success? Explain.