Stand Up and Look Around: Walking Erect

In an upright animal, eyesight becomes more important than the sense of smell. When the male genitals and female breasts became more visible, sexual attraction began shift­ing from the sense of smell to visual stimuli. In an upright posture, the male genitals are rotated to the front of the body, so merely approaching someone involves displaying the genitals. The human male has the largest penis of all primates—the chimpanzee penis averages about three inches, and the gorilla’s half that (Margulis & Sagan, 1991). I phallus Because male confrontation often involved acts of aggression, the phallus—the male

Term used to refer to the penis as a symbol of symbol of sex and potency—became associated with displays of aggression. In other

power and aggression.

words, upright posture may have also contributed to a new tie between sexuality and ag­gression (Rancour-Laferriere, 1985).

The upright posture of the female also emphasized her breasts and hips, and the ro­tation of the female pelvis forward (the vagina faces the rear in most quadrupeds) also resulted in the possibility of face-to-face intercourse. Because more body area is in con­tact in face-to-face intercourse than in rear entry, the entire sensual aspect of intercourse was enhanced, manipulation of the breasts became possible (the breasts are sexual or­gans only in humans), and the female clitoris was much more easily stimulated. Only in human females does orgasm seem to be a common part of sexual contact.

Question: Do female primates experience orgasm?

Yes, some do, though it is relatively rare compared to human females. Female primates rarely masturbate, though occasionally they stimulate themselves manually during intercourse. Bonobos (pygmy chimpanzees) do have face-to-face intercourse on occasion and may reach orgasm. However, most chimpanzees engage in rear-entry intercourse, a posi­tion that does not favor female orgasm (Margulis & Sagan, 1991).

About 200,000 years ago, Homo sapiens appeared on the scene. We do not know much about how these early ancestors behaved or what they believed. However, an­thropological evidence suggests that they developed monogamous relations and lived in fairly stable sexual pairings (Margulis & Sagan, 1991).

Timeline: Television

1927 1930 1939 1946 1947 1950

Philo T. Fransworth develops the first black-and-white television set. © Bettmann/Corbis	The Association of Motion Pictures devises a rating code to govern events portrayed in motion pictures.	Television makes its debut when the Radio Corporation of America (RCA) brings it to the World’s Fair in New York City. Here the first televised presidential debate with Franklin D. Roosevelt is shown.	First color television set is presented to the Federal Communications Commissions (FCC).

Life among early humans tended to be exceedingly difficult, with high infant mor­tality, disease, malnutrition, and a harsh environment. Living conditions began to im­prove about 11,000 years ago, when human beings discovered agriculture and began to settle down into permanent communities. Because women typically did the gathering, they understood plant life better than men. Women therefore probably first discovered how to cultivate plants, generally considered one of the two greatest discoveries—with harnessing fire—in the history of humankind.