Evolution : Is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction.
Natural Selection: Is the process through which populations of living organisms adapt and change.
Overpopulation: the condition of being populated with excessively large numbers.
Inherited Variation: Genetic variation is the difference in DNA among individuals or the differences between populations.
Struggle to survive: the competition in nature among organisms of a population to maintain themselves in a given environment and to survive to reproduce others of their kind.
Successful Reproduction: Is an individual's production of offspring per breeding event or lifetime. This is not limited by the number of offspring produced by one individual, but also the reproductive success of these offspring themselves.