What is the process of natural selection?

- Differences in genes lead to variation within a species

- It is in an individuals' best interest to produce the maximum amount of offspring in order to have maximum variation in the genes of their offspring as those with characteristics best suited to their environment will survive and pass on their genes

- Individuals who are less well suited to their environment are less likely to survive and pass on their genes to the next generation

- Over time, this leads to evolution in a species

Eg. Originally not all giraffes may have had long necks. There may have been lots of different Giraffes with lots of different neck lengths. Due to living in an environment where their main source of food (ie. leaves) could only be accessed in high places (ie. trees), those Giraffes with the long necks where more likely to be able to reach the food and survive to pass on their genes, where as the Giraffes with short necks would starve and die. Over time, this lead to Giraffes as a species having very long necks.