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Source: http://www.wsu.edu/~ice_age/lecture1.doc
Gender Role in Evolution 1. What is Gender? • Sexual identity, especially in relation to society or culture. • The condition of being female or male; biological sex. •
Females or males considered as a group: expressions used
by one gender. 2. Can evolutionary biology explain anything about gender differences in humans? • Not a popular concept – Science used to justify sexism • Stereotypes from the animal kingdom, especially nonhuman primate studies – Men are “naturally” dominant and women are “naturally” submissive – Men are “naturally” philanderers and women “naturally” try to keep them at home –
Acceptance of stereotypes forces us to resign women to a life
of oppression and men to a negative stereotype of being unable to
control their libido (Fedigan 1986) 3. Sexual Selection (Darwin, 1871) – Theory explains how sex differences evolved in animals – Similar to natural selection • Relies on individual differences in the likelihood of leaving genes in succeeding generation – Different • Works due to Individual’s ability to acquire the most or best mates, not because of survival ability – Things that give an animal a sexual advantage »
Long, pretty tails in peacocks 4. Two components to sexual selection: – Male-male competition • Results in weapons – Female choice •
Results in ornaments 5. Darwin’s (Victorian Era) ideas • Selection operates almost entirely on males • Females similar in appearance and behavior to juveniles •
Equivocated about females’ power to exercise choice in
determining which males would mate 6. Darwin’s theory of sexual selection • He believed that the human female is sexually selected by the male – Behavior and appearance • He said this was the reverse of how it happens in nature –
He didn’t say why or how 7. When humans developed “morality”…. • Self control and awareness of good and evil • Developed societies based on higher mental faculties – Tools and weapons for hunting – Accumulate property • Social stratification – Marriage practices to regulate sexual behavior •
Especially women's 8. “Equal Transmission of Characters” • “Coat-Tails” theory of human evolution • Traits are selected for in the males – Women evolve by clinging to men’s coattails •
Darwin thought this explained why men were superior to women 9. “Coat-Tails” Theory •
'With many closely-allied species, following nearly
the same habits of life, the males have come to differ from each
other chiefly through the action of sexual selection, whilst the
females have come to differ chiefly from partaking more or less of
the characters thus acquired by the males.' •
--Darwin 10. “The equal transmission of characters" •
'It is, indeed, fortunate that the law of equal
transmission of characters to both sexes prevails with mammals;
otherwise it is probable that man would have become as superior in
mental endowment to woman, as the peacock is in ornamental plumage
to the peahen.” (1874) 11. Developmental Stages of Human Civilization (19c) • Initial stage of promiscuity – Darwin disagreed; no natural analogy • Universal matrilineal stage – Kinship between mothers and children only recognized – Fathers’ relationships to children not recognized • Universal patrilineal stage –
Women could return to their “natural” place in the home,
protected by men 12. Ages of Men (Cartoon) 13. Fritz Engels (1884) • Matrilineal promiscuous societies – Most likely egalitarian • Invention of agriculture brought accumulation of property – More important to men • Patrilineal descent systems – instituted to give men more control over the disposition of their property •
Including women and children 14. What happened to 19c Theories? • Darwin’s ideas on human social and racial evolution were largely dropped or forgotten – Founded on weak or incorrect evidence •
19c ideas of social evolution were refuted or discredited in
the first half of the 20th c 15. “Man the Hunter” Theory • Theory arose in the 20th century • Hunting as “the master behavior pattern of the human species.” • Hunting as catalyst for all technological, social, and intellectual achievements of human beings • Shaping force of human psyche for all time •
Some also credit gathering plant foods, but most failed to
mention any other means for procuring food 16. Sex Roles Derived from “Man the Hunter” Theory • Essentially similar to Darwin’s • Men: – Actively and aggressively procuring food and defending their families • Women: – Dependents who stay close to home and trade sexual and reproductive capacities for protection and food • Assumes that women do no hunting – Effectively omitted the female half of the species from any consideration 17. “Woman the Gatherer” • Proposed by Sally Linton in 1971 • Patterns exhibited by hominid females a logical extension of the intense mother-infant bond in all primates – Her model showed early hominid females gathering, carrying, and sharing food with their young – Earliest “containers” invented to carry young and gathered foods • Hunting of large mammals by males was a late development •
Sexual bonds and sexual exchange were not the cornerstone of
society 18. “Woman the Gatherer” • Explanation for bipedalism – Refuted earlier claims re: hunting as impetus – Need to have hands free to gather plant foods as strong stimulus for walking upright • Plants, not meat, as the most important food –
Not meat procurement focus for technological or social
innovation for emerging hominids 3 million years ago 19. The “Sharing” Model • Early 1980s – Sexual division of labor occurred late in hominid history – Early hominids had to cooperate to survive • Hovering precariously on the edge of extinction – Needed to accumulate surplus food through production – All members of the group shared all food obtaining practices and subsequent exchange – Invention of fire and projectile weaponry by late Homo Erectus marks beginning of sexual division of labor •
Division of labor a very expensive practice 20. The Primate Evidence 21. Justification Because humans are
members of the order Primates, study of our nearest relatives can
help us to understand both the ways in which we are similar to them
and the ways we are different 22. Baboon studies • 1956-1960 – DeVore and Washington • Observed common baboons in East Africa • Constructed a model of early hominid behavior •
Model was popular in the 60s and 70s 23. Baboon model • Hominids as predators and as prey • Social system of defense • Bonding and cooperation of mature males organized into a rigid dominance hierarchy • Employed an “army like” pattern of “troop movement across the savannah • Carefully structured defense formation – Females and young in the center •
System encouraged males to further distinguish themselves via
inventing weapons and hunting, and unique human traits like families
and language 24. Criticisms of the Model • The portrayal of primeval sex roles in the model are consistent with contemporary role expectations for Western men and women – Males were seen as aggressive, competitive, and protective – Females were seen as nurturing, dependent and submissive •
In other words, the theory reflects the thinking of its time 25. Chimpanzees • Evidence points to chimps as the nonhuman primate most closely related to humans – Presumably, this fact may not have been as evident or widely known at the time of the baboon study •
Chimps show patterns of rudimentary behavior that may be
similar to that of human ancestors 26. Chimpanzees • Some patterns of chimp behavior resemble those that became distinguishing characteristics of humans •
Researchers believe that chimps’ traits can give us a clue
to the general “ape-like” way
of life of early human ancestors
27.
Chimp characteristics • Form matrifocal social bonds – Males’ ties are to their matrifocal unit rather than their mate • Females are primary tool users – Food gathering – Males use tools to hunt small animals • Food sharing – Adult males share meat with older males and their female kin –
Females share surplus plant food with their offspring
28. Chimps and early hominids • Some models continue the emphasis on males as the main actors in the development of distinctive human abilities – Male chimpanzee aggressiveness and hunting patterns • Some models focus on the females as the prime movers in the evolution of food sharing and tool use –
Matrifocal social units, female tool use and food sharing–
29. Ethnographic Evidence • Using current-day hunter-gatherer societies today as a model – Some debate about whether this is logical or ethical – Modern foragers are not “fossils” of the Pleistocene •
Evidence points to people of the Upper Paleolithic making a
living as foragers or hunter-gatherers•
30. Basic features of a generalized hunter-gatherer society • Flexible • Bilaterally organized • Nonterritorial • Genealogical core consisting of both males and females • Egalitarianism •
Lack of division of labor 31. Role of women in hunter-gatherer societies • Foods acquired from hunting – only about 35% of diet • Most depend more on gathering – done by women •
Foraging women are generally capable of feeding themselves
and are not dependent on men for subsistence 32. Women don’t just gather • Studies have found that in many foraging societies, woman also hunt small game – Sometimes also hunt large game • Meat consumption of a group doesn’t necessarily define the sex roles or contributions to subsistence •
The idea of the non-productive female in early societies is
probably erroneous 33. The Tasaday • Small group of foragers in the Philippines • No outside contact until the 1960s • Egalitarian • No sexual division of labor • No hunting or trapping • Collected small animals to supplement their vegetable diet • Simple technology •
Food sharing
34. Fossil evidence for early hominid sex roles • All that remains to work from are: – Bones – Stone tools – Environmental and contextual information – Physical traces of activities • Some evidence is material, some is inferred – Inference and interpretation must occur in every description, at every level –
We use inferences and interpretations to construct models
that can be tested
35. Fossil evidence for early hominid sex roles • Early hominids lived in East Africa about 3 million years ago • They walked on two feet • They had human-like teeth – Small canines and thickly enameled molars • May have spend some time in the trees but mainly lived on the ground •
Eventually lost their hairiness•
36. What Lucy had for dinner • Inferred from teeth – Teeth are very specialized – Omnivorous – At a variety of foods, including soft fruits and fibrous plant foods – No clear specialization for meat-shearing or seed grinding or bone gnawing – Canines are relatively small •
They are larger in males in most primate species
37. Home bases • Early researchers argued for hominid “home bases” at which the females, young and elderly “hung out” and waited for the males to bring home the bacon. – Fossil evidence: caches of tools and bones • Recent work has disputed that theory – Dangerous -- Leaves hominids open to become food for carnivores, at least until the invention of fire –
Bones included both cut marks and carnivore gnaw marks
38. Hominid sex roles • Probably very little sexual division of labor – Expensive – Females probably not as immobile as some “Man the Hunter” theorists believed – Diet was probably varied and not meat-dependent •
The need for females to remain productive and mobile even
while raising young may have been the “mother of invention” for
a number of tools
39. When did humans adopt sex roles? • Big game hunting probably not a good idea for females – Hominids lived in small groups, and the loss of females of childbearing age in hunting accidents would have been a serious blow to the viability of the group – Mobility would be restricted if females participated in hunting while carrying their small children, who could also make noise at a bad time –
They would gradually stop participating and that would
eventually fossilize into a social pattern
40. When did humans adopt sex roles? • Change of environment when hominids first entered Europe – Colder conditions; meat may have become a more important food source – Onset of glaciation during the Ice Age would have exacerbated this need • Climate became much colder and vegetation much more sparse – Hunting large animals like mammoths very dangerous but not a regular source of food • Only part of the community hunted mammoths •
Rest of the community stayed near home and gathered plant
foods and small animals
41. Conclusions • Theories like “Man the Hunter” and “Woman the Gatherer” are probably inadequate to describe hominid sex roles • There was probably not a pronounced sexual division of labor • Both sexes would obtain food and share it with the rest of the group • Males probably were the major participants in big-game hunting, beginning about 100,000 years ago
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