什么是 自然选择？

Intelligence wasn't maximized before the Bronze Age because ancient societies prioritized traits like strength and religiosity over intelligence. Modern emphasis on intelligence is a historically unprecedented phenomenon, as David Reich explains natural selection's dependence on societal values.

Genetic variants face evolutionary trade-offs: the TYK2 variant once protected humans against ancient diseases but became a risk factor for severe tuberculosis after its spread, revealing the inherent conflict in immune system optimization.