Variation

This lesson covers: 

1. What variation is
2. The causes of variation
3. Continuous variation and discontinuous variation

Variation

Variation means that no two living things are exactly alike.

There are always differences between individuals in a population, and these differences are called variations.

Causes of variation

Variation between individuals is caused by genetics, environmental factors, or a mixture of both:

1. Genetics - The genes you inherit from your parents are unique to you, and they code for characteristics like eye colour and blood group.
2. Environmental factors - The environment we experience impacts our characteristics, like piercings, injuries, and nutrition.
3. Genetics and environmental factors - Most variation is actually the result of a mixture between genetic and environmental factors.

For example, two individuals might have different levels of muscle due to genetics, but exercise (an environmental factor), may mean the less genetically muscular person is more muscular.

Continuous and discontinuous variation.

There are two types of variation.

1. Continuous variation
2. Discontinuous variation

Continuous variation

Continuous variation is when a characteristic exists along a full range of differences.

• Human height is an example of continuous variation.
• Height ranges from very short to very tall, with every possible height in between.
• Other continuous characteristics include skin colour, weight, and IQ.

Discontinuous variation

Discontinuous variation is when a characteristic only has specific, distinct options, or groups.

• Tongue rolling is an example of discontinuous variation.
• You are either able to roll your tongue or you are unable to roll your tongue
• Other discontinuous traits include eye colour, earlobe attachment, and blood group.