Natural Selection and Genetic Modification

Darwin and Alfred Russel Wallace both independently developed the theory of evolution by natural selection.

Darwin's theory of evolution by natural selection:
1. There is variation within a population (caused by mutations and sexual reproduction)
2. Individuals with advantageous characteristics are more likely to survive
3. These individuals are more likely to reproduce and pass on their alleles
4. Over many generations, the proportion of the population with the advantageous trait increases

Evidence for evolution: fossil record, antibiotic resistance in bacteria, comparative anatomy.

Speciation occurs when populations of the same species become isolated and evolve differently until they can no longer interbreed.