How does continuous variation differ from discontinuous variation?

Continuous variation shows a range of small differences, while discontinuous variation shows distinct, separate categories or groups.

Continuous variation refers to the type of genetic variation where the individuals show a range of small differences rather than distinct categories. This type of variation is usually the result of the influence of multiple genes (polygenic inheritance) and environmental factors. Examples of continuous variation include height, weight, and skin colour in humans. These traits do not fall into distinct categories but rather show a range from one extreme to another, such as from short to tall or light to dark skin.

On the other hand, discontinuous variation refers to the type of genetic variation where the individuals fall into a few distinct categories rather than showing a range of small differences. This type of variation is usually the result of the influence of a single gene or a small number of genes. Examples of discontinuous variation include blood type, eye colour, and the ability to roll one's tongue in humans. These traits fall into distinct categories, such as blood type A, B, AB, or O, and there is no intermediate between these categories.

In summary, the key difference between continuous and discontinuous variation lies in the range of variation and the number of genes involved. Continuous variation shows a range of small differences due to the influence of multiple genes and environmental factors, while discontinuous variation shows distinct categories due to the influence of a single gene or a small number of genes. Understanding these differences is crucial in the study of genetics and evolution, as it helps us understand how traits are inherited and how populations change over time.