The reflex to stand your ground or run away has been shaped by hundreds of thousands of years of evolution, in response to predators and other environmental threats. (moneysense.ca)
We were set on having a natural birth and letting thousands of years of evolution do its work. (babycenter.com)
They are the result of the most astonishing experiment in breeding ever undertaken — imagine speeding up thousands of years of evolution into a few decades. (aaas.org)