Evolution & Darwin

1. Evolution & Darwin If humans share a common ancestry with other primates, then we can learn about our own development understand our behaviour better by studying them.

2. Voyage of the H.M.S.Beagle • Dates: February 12th, 1831 • Captain: Charles Darwin • Ship: H.M.S. Beagle • Destination: Voyage around the world. • Findings: evidence to propose a revolutionary hypothesis about how life changes over time

3. Voyage of the Beagle

4. Darwin was fascinated by the land tortoises and marine iguanas in the Galápagos. Giant tortoises varied in predictable ways from one island to another. The shape of a tortoise's shell could be used to identify which island a particular tortoise inhabited. The Galapagos Island

6. James Hutton: 1795 Theory of Geological change Forces change earth’s surface shape Changes are slow Earth much older than thousands of years Ideas that shaped Darwin’s Thinking

7. Charles Lyell Book: Principles of Geography Geographical features can be built up or torn down Darwin thought if earth changed over time, what about life? Ideas that Shaped Darwin’s Thinking

8. Population Growth • Thomas Malthus-19th century English economist • If population grew (more Babies born than die) • Insufficient living space • Food runs out • Darwin applied this theory to animals

9. Natural Selection (Variation) & Artificial Selection • Natural variation--differences among individuals of a species • Artificial selection- nature provides the variation among different organisms, and humans select those variations they find useful.

10. Evolution by Natural Selection • The Struggle for Existence-members of each species have to compete for food, shelter, other life necessities • Survival of the Fittest-Some individuals better suited for the environment

11. Summary of Darwin’s Theory • Individuals in nature differ from one another • Organisms in nature produce more offspring than can survive, and many of those who do not survive do not reproduce. • Individuals best suited for the environment survive and reproduce most successful • Species change over time

12. Primate Evolution Darwin did not specifically address primates in His famous Origin of the Species

13. Primates are mammals that have: • Opposable thumbs • Large brain • Good, stereoscopic vision • Ability to brachiate* • Flexible elbows for hand rotation • Grasping feet * swing from tree limb to tree limb using only their arms

14. Early Primates • Appeared 60-65 million years ago • Prosimian • Small bodies • Lemurs, Tarsiers • Anthropoids • Human-like primates • Evolved in Africa

15. Hominid Evolution Lucy and Ardi VIDEO • Hominids developed 5-8 million years ago • Hominids are bipedal • First hominids were in genus Australopithecus • “Lucy” most famous fossil hominid • “Ardi” is the oldest Hominid • More modern hominids were in genus Homo Examine the Evidence: Primate skeletons: -Long fingers and toes are good for climbing trees -Short legs are helpful for moving around in trees -Wide and short pelvis suggests upright posture -Thigh bones angle in toward knees, making upright walking easier

16. More Recent Humans • Homo sapiens • (Developed 400,000 years ago) • Neanderthals • Europe arrival (100,000 years ago) • Cro-Magnon • Europe arrival (40,000 years ago) • Americas arrival (12,000 years ago)

17. Primates and Humans Power, Sex, Kindness, Grudges Chimp – (Pan troglodyte) Bonobo – (Pan paniscus)

18. What is Power? And Status? What does it mean to have it, or not to have it? Student ideas about power: … … … Student ideas about privilege: … … … …

19. Power and Status • Wealthmay be an excellent thing, for it means power, and it means leisure, it means liberty. James Russell Lowell • If those in charge of our society - politicians, corporate executives, and owners of press and television - can dominate our ideas, they will be secure in their power. Howard Zinn • When I see how we treat one another; the war, the crime, the inhumanity... I wonder a million years ago whether we crawled out of the slime or were asked to leave. Milt Abel • Wild animals never kill for sport.  Man is the only one to whom the torture and death of his fellow-creatures is amusing in itself.James Anthony Froude

20. Discuss... • Think about the ways in which you have or use power: • At home – over younger brothers/sisters • At school – over team/committee members • Your community – over the street-kid • Globally – over the enslaved cocoa-bean picker • Why do humans have a lust for power; is it nature or nurture? • E.g. In the 1970s human behaviour was seen as cultural, not natural. So, to make people ‘better’, change the culture.

21. Primate Power Relations • What does great ape (chimp, bonobo, gorilla, orangutan - our closest relatives) behaviour tell us? • E.g. Chimps – hierarchy/status is all important • Male power is always up for grabs – determined by who can beat whom [Female status is recognized, not contested] • Coalitions are necessary – Power relations!

22. Arnhem Zoo: Liut, Nikkie, Yeroen • Three males in the Arnhem Colony, Arnhem, The Netherlands • Alpha males display aggression, hair on end, hitting any who don’t move away in time – Keeping track of those who don’t bob & grovel with pant-grunts • When the older Yeroen was Alpha, the stronger Liut challenged – After 3 months of being chased up trees, feigning injuries to get support...Yeroen eventually showed the required submission • The next year, Yeroen teamed with Nikkie – How? Yeroen exploited tensions among younger males by watching disputes flare, then stepping in to support one side. • Built relationship with Nikkie - lots of • grooming time – Liut knew and regularly • charged in to break it up • Eventually, Liut submitted to the new • Alpha: Nikkie

23. Nikke & Yeroen’s Reign • Ruled as a team for 4 years ... • Benefits of status: for female chimps, food; for male chimps, prestige and sex - Yeroen could have any • Over time, a bolder Nikkie restricted Yeroen’s benefits – A split! - Liut took over as new Alpha • Soon Nikkie & yeroen teamed up again – tension in the colony increased • In times of leadership tension, chimp males stay close – “Keep friends close, enemies closer” • One night, the three would not separate when escorted to night cages – Nikkie & Yeroen ganged up on Liut – killing & emasculating him • In the morning , the colony refused to eat breakfast – Nikkie was chased up a tree by a female ally of Liut’s

24. Humans and Status Recognition • Japan – the depth of greeting bow signals men-women, and senior-junior family rank differences between men and women, and senior • Saddam Hussein had his underlings greet him with a kiss on his armpit • Larry King Live – King would adjust the timbre of his voice to that of high-ranking guests; low ranking guests adjusted their timbre to match King’s – • In all 8 US Pres. Elections 1960-2000, popular vote went to the one who held his own timbre • For the Physical Anthropologist – Power Relations are ingrained in human cultures

25. Patrols, Raids, and Death Squads • Xenophobia - Fear and contempt of strangers or foreign peoples • Humans and chimps are xenophobic – they are the only animals in which gangs of males expand their territory by deliberately exterminating neighbouring males (Rwanda) • Is warfare in our DNA? • One aspect of human behaviour chimps cannot illuminate is something we do even more than wage war... maintain peace

26. Some Questions If human drive for power and status is part of evolutionary history, are we doomed to live with strife and injustice? What would humans be like- what would be lost – if we did not pursue power and status? If we are to put a check on the drives of our ‘inner ape’, how can we do this?

27. Bonobos – The Politics of Sex "Sex is there, it's pervasive, it's critical, and bonobo society would collapse without it," he said in an interview. "But it's not what people think it is. It's not driven by orgasm or seeking release. Nor is it often reproductively driven. Sex for a bonobo is casual, it's quick and once you're used to watching it, it begins to look like any other social interaction."

28. Bonobos and Sex A zoo keeper used to working with chimps is introduced to bonobos, and accepts a kiss from one of his new primate friends. For chimps, a kiss is friendly vs. sexual. The zoo keeper was taken aback when he felt the bonobo’s tongue in his mouth! For bonobos, erotic contact mixes freely with everything else they do. E.g.- sex is used every day to iron out ‘wrinkled relationships’ (= make-up sex) Most of their sexual activity has nothing to do with reproduction. It frequently involves member of the same sex – there are no exclusively hetero- or homosexual bonobos

29. Bonobo Sex and Society Sex is very casual and well-integrated with bonobo social life Female chimps are swollen (genital) less than 5% of adult life...Female bonobos are in this state close to 50% Young females present themselves to males who have food – after sex, they share To put a halt to infanticide (well documented among chimps and gorillas), bonobos evolved a female dominated, sexualized society in which paternity is a mystery Females are dominant – a male has status (i.e. access to food and sex) according to the status of his mother (the Alpha male is the son of the dominant female)

30. Making Love, Not War • Peaceful mingling between bonobo groups (Note: female bonobos migrate) contrasts with how chimp groups interact • Bonobos show the ways in which peaceful relations can evolve: intermarriage, gene flow between groups, makes deadly aggression counter-productive • Darwin believed that ethics/morality grew out of cooperative impulses and impulses that might harm the group on which we depend for survival – on learning reciprocity (De Waal, p. 207) • While human warfare exceeds the chimps’, human inter-group relations also exceeds the bonobos’ • Our societies are never completely competitive, never completely peaceful

31. Physical Anthropology Conclusion What we can learn by observing the relatives who share almost all of our DNA

32. What is Uniquely Human? • List some qualities/characteristics that clearly differentiates us from the great apes:

33. Is it...Sympathy? • Chimps – who cannot swim – have drowned trying to save other chimps • After a fight between two chimps, others would console the loser • Rhesus monkeys, given the chance to get food by pulling a chain that would also give an electric shock to a companion, will starve themselves for several days

34. Possible Implications • Physical/Biological Anthropologists argue that human morality grew out of these types of behaviours • Evolutionary Biologist Marc Hauser proposed in Moral Minds that the brain has a genetically shaped mechanism for acquiring moral rules • Anthropologists do not argue Chimps have morality, but rather that human morality would be impossible without certain emotional building blocks that are at work in chimp/bonobo/monkey societies • To console requires empathy and a level of self awareness that only apes and humans possess

35. Is it...Reconciliation? • If two chimp males fail to make up, female chimps will often bring the rivals together – as if sensing that the discord makes the community worse off • Sometimes females will head off a fight by taking stones out of the males hands • Chimps (and others, like macaques monkeys) have a sense of social order, and sometimes act for the greater good of the group • This is a significant precursor of human morality

36. Is it...Reciprocity? • Chimps are more likely to share food with those who have groomed them • Capuchin monkeys show their displeasure if given a smaller reward than a partner did for performing the same task • Empathy, peace-making, following social rules, and reciprocity are the basis of sociality • Human sociality adds two levels of sophistication: • human societies enforce moral codes more rigorously – with rewards, punishments, and reputation building • they also apply a unique degree of judgment and reason

37. Disagreements • Evolutionary Biologist George Williams dismisses morality as an accidental by product of evolution • Psychologists object to attributing any emotional state to animals • Philosopher Immanuel Kant believed morality must be based on reason, while David Hume believed moral judgments proceed from emotions • More recently, Jesse Prince argued that moral sentiments are shaped by culture, not genetics

38. Concluding Points • Anthropologist’s work challenge the idea that there is a uniquely human behaviour • Anthropologists and moral philosophers have recently begun a dialogue about human morality and its origins • From an evolutionary point of view, primate social behaviour suggest how human social behaviours and ethical codes may have developed