Provide a definition and an example for each of the following terms:

polygenic inheritance

Key Concepts

Polygenic Inheritance

Polygenic inheritance refers to the genetic mechanism where multiple genes (often located on different chromosomes) contribute to a single trait. This results in a continuous range of phenotypes, rather than discrete categories. For example, human height is influenced by several genes, leading to a wide variety of heights in the population.

Quantitative Traits

Quantitative traits are characteristics that are influenced by multiple genes and can be measured on a continuous scale. These traits often show a normal distribution in a population due to the additive effects of alleles. Examples include traits like weight, skin color, and intelligence, which are not simply 'present' or 'absent' but vary in degree.

Environmental Influence

Environmental influence refers to the impact of external factors on the expression of genetic traits. In polygenic inheritance, the phenotype can be significantly affected by environmental conditions such as nutrition, climate, and lifestyle. For instance, two individuals with the same genetic predisposition for height may end up with different heights due to variations in their nutrition during growth.