Hi,
Some of my points overlap others, but here goes...
Recent observed changes in a particular human population within the last few hundred years is not the same thing a evolution (i.e., a change in the frequency of alleles through successive generations), such as changes in eye sight or even taller human beings today than the Middle Ages. Environmental factors are affecting these, such as a higher percentage of people reading or a change in diet.
Some have made comments about earlier generations indeed having eyesight problems, and I'm sure this was the case during hunter-gatherer times. In a hunter-gatherer society, the oldest individuals (those most likely having the worst eyesight) most likely have changed their group contribution to activities not requiring acute eyesight. Also, when you watch today's hunter-gatherers hunt, they hunt in groups. I can easily see the older experienced hunters in charge and evaluating tracks, while the younger "well-sighted" individuals learning this skill but also doing their part by identifying prey at great distances. Not everyone needs to have keen eyesight in order to have an affective hunting team.
Great thread.
best,
Edited by Jeff Davis, : No reason given.
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