Variation refers to the unique characteristics that differentiate individuals of the same species. For example, different people can have different eye colours.
Variation between different species tends to be greater than the variation between individuals of the same species. This variation means that some organisms compete more successfully, which can drive natural selection.
There are two main categories of variation:
Genetic variation refers to the differences in characteristics that are caused by the genetic information passed down from an organism’s parents. This can include traits like eye colour, blood group, skin colour and hair colour.
When an organism reproduces, it passes on some of its genetic information to its offspring, which is why children often resemble their parents but are not identical to them.
Some examples of inherited variation are:
Environmental variation refers to differences in certain characteristics that are caused by external factors in an organism’s surroundings. These external factors can include diet, lifestyle choices, and climate.
Environmental factors determine characteristics such as:
For example, tattoos are not inherited; they are a result of a lifestyle choice that can make a person stand out from others.
Many characteristics, such as height and weight, are influenced by both genetic and environmental causes of variation. For example, a person’s genetic information, inherited from their parents, may determine their potential height or weight. However, environmental factors, such as nutrition and lifestyle, can also play a role in these characteristics.
Therefore, both genetic and environmental causes of variation play a part in determining these characteristics.