2.23 : 遗传性

Heritability measures the genetic influence on traits or physical characteristics such as height or eye color.

Heritability can vary depending on the group and the conditions in which they live.

For instance, human height is 90% heritable, but nutrients and exercise significantly influence it.

When everyone in a group, like all children in this family, lives in a similar environment, differences in their traits, like height or personality, are more likely to stem from their genetic factors.

Conversely, if one of the children is more physically active and has a healthier diet, the differences between the siblings' physical characteristics may be due to environmental rather than genetic factors.

Historical data on physical traits further illustrate the impact of the environment. For example, the global average height of both men and women increased by around 10 cm over the past 100 years, reflecting improvements in nutrition and healthcare.