Final answer:
To conclude that the average increase in height represents an evolutionary change, we would need to show that it is heritable and that taller individuals have a reproductive advantage.
Step-by-step explanation:
The increase in average height of humans over historical times can be considered an evolutionary change if certain conditions are met. We would need to show that this increase is heritable, meaning that it is passed on from one generation to the next through genetic variation.
We would also need to demonstrate that taller individuals have a reproductive advantage over shorter individuals, leading to the spread of the genes associated with taller height in the population over time.
Studies have shown that height is influenced by genetic factors, with estimates suggesting a heritability of around 80%. This means that a significant portion of the variation in height among individuals is due to genetic differences.
Additionally, certain genetic conditions that affect growth and development have been found to contribute to shorter stature. This suggests that there is a genetic component to height.
In terms of reproductive advantage, it is possible that taller individuals are perceived as more attractive and have higher chances of finding a mate, which can increase their reproductive success. However, other factors such as health, socioeconomic status, and access to resources can also influence reproductive success.