Quotes About Selection pressure

The large male penis is a product of female choice in evolution. If it were not, males would never have bothered to evolve such a large, floppy, blood-hungry organ. Ancestral females made males evolve such penises because they liked them.

The likelihood that, in attacking a member of your own species, you will get hurt is a powerful selection pressure that disfavors indiscriminate pouncing or lashing out.

Marc Kirschner and his Berkeley colleague John Gerhart.20 They wondered whether modern creatures have cellular and developmental mechanisms with the characteristic of what is called evolvability. That is, do they have the ability to generate heritable phenotypic variation? And is the characteristic of evolvability itself under selection pressure? That is, will biological systems that produce more phenotypic variations that can be passed on to their offspring be more