Evolutionary mechanisms

The evolution of species occurs when the genes of the individuals that constitute it change in a population. These variations can be produced by:

• Changes in the proportion of alleles in the population.
• Entry of new alleles into the population, by mutations or by the arrival of individuals from other populations.

The evolution occurs for these reasons: 

• Genetic variability.
  • Mutations.
  • Genetic recombination.
  • Genetic drift.
  • Gene flow.
• Natural selection.