ANTC23H3 Lecture : Sexual Dimorphism
Document Summary
External traits that help distinguish the sex of an individual, but are not directly involved in reproduction. Flanges and throat sac (laryngeal sac) of orangutan males. Testosterone-mediated traits (only in males who are in or past puberty) Potentially indication of if they are able to reproduce, honest indicators of male quality, dominance, etc. Sexually dimorphic trait, controlled, typically, by estrogen and other hormones. Human women whr, breast size, etc. are the same as cycling/estrus/lactating female non- human primates. Evolved via female-female competition as an indication of female quality. Amount of body fat indicates ability to successfully reproduce and have enough nutrition to be pregnant/lactate. Problem because breast size is not related to milk production or fertility success. Breast size is not largest when ovulating but during pregnancy and lactation. Differences in body size usually caused by larger size of males. Adaptive trait because it aids in mating success.
