Continuous variation

Definition

Continuous variation is the range of small differences we see among individuals in a characteristic, which results from the combined effect of many genes and environmental influences. It contrasts with discrete variation, where traits fall into distinct categories.

5 Must Know Facts For Your Next Test

1. Continuous variation often produces a bell-shaped curve when graphed due to the normal distribution of traits.
2. Traits showing continuous variation include height, skin color, and weight in humans.
3. Polygenic inheritance is a key factor that contributes to continuous variation.
4. Environmental factors can influence traits that exhibit continuous variation, adding to the genetic effects.
5. Mendel's laws primarily explain discrete traits but can be extended to understand polygenic traits contributing to continuous variation.

Review Questions

• What type of graph typically represents continuous variation?
• Name three human traits that exhibit continuous variation.
• How do environmental factors influence continuous variation?

Related terms

Discrete Variation: Traits that fall into distinct categories, such as blood type or flower color in Mendel’s peas.

Polygenic Inheritance: A single trait controlled by two or more genes, which often leads to continuous variation.

Normal Distribution: A statistical distribution where most occurrences take place around the mean value, creating a bell-shaped curve.