1. Some individuals are at a selective advantage over others for a given selection pressure.<br/><br/>2. The cycle repeats over many generations and thousands of years.<br/><br/>3. these individuals are more likely to pass on the advantageous allele to the next generation.<br/><br/>4. variation exixts amongst individuals in a species.<br/><br/>5. in turn these offspring are more likely to survive and pass on the advantageous allele.<br/><br/>6. individuals with a selective advantage are more likely to survive to reproduce.