It is still not fully understood why the negative selective pressure on these regions is so much stronger than the selection in protein-coding regions.
These cultivated plants lack seed dormancy because of generations of selective pressure by plant breeders and gardeners that grew and kept plants that lacked dormancy.
He believes that rudimentary symbolic communication appeared early on and created a new selective pressure that favored development of linguistic ability and hence the brain.
This imposes a selective pressure on the colonies, as the arthropods collected from these raids represent nearly half of the food consumed by the ants.
Life on the veldt was tough, and prehistoric humans' genes were constantly subjected to selective pressure in an environment where the species' survival depended on it.