Original: "What was new was Lubbock's... insistence that, as a result of natural selection, human groups had become different from each other, not only culturally, but also in their biological capacities to utilize culture".
Simplified: "What was new was Lubbocks... insistence that, as a result of natural selection, human groups had become different from each other, not only culturally, but also in their biological capacities to utilize culture".