2: Darwin and Wallace Proposed Two Theories of Evolution
1. The living organisms we see today are all related by descent (common ancestry)
2. The means by which evolution occurs is a process of ‘natural selection.’
- organisms differ from one another i.e., there is variation
- these differences are heritable, i.e. passed from generation to generation
- many more organisms are born than survive and reproduce (mortality)
- therefore, any variation that makes one offspring more successful than another will have a greater chance of being passed to the next generation (“survival of the fittest”)