Those individuals that leave the greatest proportion of descendents in a population have the greatest influence on the heritable characteristics of the population. Thereby, characteristics that are favorable in a particular environment tend to increase in frequency. Proposition of the Theory of Evolution by Natural Selection Individual that make up a species are not identical. They show variation. Some of this variability is heritable.
All populations produce more offspring than what is necessary for replacement.
Different individuals leave different numbers of decendents. Number of descendents depend on the interaction between the characteristics of the individual and the environment of the individual. The Hardy-Weinberg Law predicts that there will be no change in gene frequencies from one generation to the next. No Mutations Violation of the Assumptions of the Hardy Weinberg Law are events of evolution. Directional Selection Disruptive Selection Fitness Fitness is measured by comparing the number of offspring produced by one genotype to that produced by another.