Answer to Question #159824 in Biology for avantae n mccoy

Question

 A major point of understanding natural selection is that not all organisms in a population get to reproduce. Consider the term fitness as used in biology. How does this term relate to natural selection? 

Answer 1

Fitness is the quantitative representation of natural and sexual selection and describes individual reproductive success. Fitness can be defined either with respect to a genotype or to a phenotype. Natural selection can cause a change in allele frequencies, with fitness-increasing alleles becoming more common in the population.