Continuous Variation

What is Continuous Variation?

Variation in which the phenotypes of a species form a range between two extremes, with intermediate values possible at any point along that range. Continuous variation is measured rather than counted, is usually influenced by many genes acting together with the environment, and produces a smooth frequency distribution when plotted. Body length and body mass are the standard Cambridge O Level Biology examples, and the correct graph is a histogram with touching bars or a frequency distribution curve.

This definition is part of the Inheritance chapter in Cambridge O Level Biology.

Concepts related to Continuous Variation

• histogram
• frequency distribution
• polygenic
• environment

Common mistakes with Continuous Variation

• “Continuous variation is controlled only by genes.” It is usually influenced by many genes and by the environment, and that combination is what produces a smooth range rather than distinct groups. Write “Continuous variation is usually caused by many genes acting together with the environment.”