Explain how genetic variation and environmental pressures can lead to a change in the characteristics of a population.

Some characteristics of an individual are caused by the environment. For example, the language we use, or whether we have scars, are environmental characteristics. Other characteristics are inherited.

Here are some inherited characteristics:

Some characteristics - including intelligence, body mass and height - are the result of both environmental and inherited factors. But there is debate about the relative importance of the two types of factor in some human characteristics, such as intelligence, health and sporting ability.