Natural selection

• Individuals that have adaptations that are the best for the environment they live in survive to reproduce and pass their alleles on to the next generation. This is natural selection.
• Populations typically produce too many offspring for the environment, there is competition for survival. Individuals with the best adaptations will survive and reproduce (fitness).
• Passing these alleles to offspring will increase there frequency in the gene pool.
• Environmental factors are selecting agents. When they change, different phenotypes will be selected for.
• Favourable alleles will increase in frequency in the gene pool while unfavourable will decrease. If the frequency of alleles changes, evolution is occuring.
• If a population becomes reproductively isolated from other populations, it is then a new species.