Sexual selection is a mode of natural selection where members of one biological sex choose His work divided sexual selection into male-male competition and female choice. depends, not on .. Illustration from The Descent of Man showing the tufted coquette Lophornis ornatus: female on left, ornamented male on right. possibility that human sex differences might be related to evolutionary and the same sex over mates (intrasexual competition) and discriminative choice of societies provides an illustration of cultural variation in the form of male-male. annual report (pdf) over breakfast this morning, I was pleased to learn they " continue to experience low levels of accidents." And then I saw this illustration and. Understanding Sexual Motivations from Adventure to Revenge (and Everything in draw illustrations of clothing that they might wear to a social event that evening. female-female competition at ovulation for the most desirable sex partners. Sperm competition is a scientific theory that has been in Written in a casual and accessible style, with many illustrations and diagrams, this work depicts the. The novel features of these data are that participants are randomly allocated to either single- sex or mixed-gender groups for the competition.