Variations are differences in characteristics within a species. There are two types of variations which are discontinuous variation and continuous variation.
Discontinuous variation
Discontinuous variation has distinct categories into which individuals can be placed. Discontinuous variation is controlled by one gene or a small number of genes, is unaffected by the environment and is usually represented by discrete bars in a graph. Examples of discontinuous variations are human blood group, ability to roll tongue, types of ear lobes and others.
Continuous variation
Continuous variation has no distinct categories into which individuals can be placed. Continuous variation is controlled by a large number of genes, is affected by the environment and is usually represented by a histogram in a graph. Examples of continuous variations are height, weight, skin colors and others.