AnthropologyEvolution

PrimatologyHuman AncestryPhysical variation

EVOLUTION• 8th C/19th C: Evolution was a viable theory• C. Linneaus (1707-1778): classified plants & animals

in a systema naturae which placed humans in the same order (Primates) as apes & monkeys

• J. B. Lamarck (1744-1829): species were not fixed in form. Acquired characteristics could be inherited.e.g. giraffes

• G. Cuvier (1769-1832): Catastrophism: changes in the earth & fossil record. E.g. Noah’s flood

• Hutton & Lyell: Uniformitarianism - Natural forces constantly shape and reshape the earth. Species evolved thru natural selection

EVOLUTIONCHARLES DARWINOrigin of Species by Means of Natural Selection (1859)The Descent of Man (1871) • Natural Selection (variety, heritability, differential

reproductive process). • Primate origins (similarities between apes and

humans)

• Charles Darwin and Alfred Wallace – mechanism of Natural Selection

Every specie consists of various individuals, some of which are better adapted to their environment than others (Variation)

Offspring inherit traits from their parents (Heritability)

Since better adapted individuals produce more offspring through time than the poorer adapted, the frequency of adaptive traits increases in subsequent generations. (Differential Reproductive Success)

Sources of Biological Variation Genetic Recombination – A unique offspring is produced by a shuffling

of the parents’ genes.

Random segregation - sorting of chromosomes in mieosis (the process by which the reproductive cells are reproduced).

Crossing-over - the exchange of sections of chromosomes between one chromosome and another.

Mutation – change in the DNA sequence (chemical substance which controls heredity). Ex. Galactosemia caused by recessive gene and usu. result in mental retardation and blindness.

Genetic Drift – refers to random processes that affect gene frequencies in relatively isolated population

Gene Flow – genes pass from one population to another through mating and reproduction

QUESTIONSDo you think the theory of natural selection

is compatible with religious beliefs?How might the discovery of genetic cures &

the use of genetic engineering affect the future of evolution?

Why do you think humans have remained one species?

BIPEDALISMHuman beings are proficient in the mode of locomotion known as bipedalism or walking on two legs. Imagine that you have been hired to write copy for an “owner’s manual” of the human body. On a sheet of paper, provide detailed instructions for standing from a seated position (without using the hands) & moving forward for about 5-10 feet using only the legs.

Primatology• We can infer how and why

humans diverged from the other primates

Common Features of Primates• Two bones in the lower part of the leg and in the

forearm• Collarbone/Clavicle• Flexible prehensile (grasping) hands• Stereoscopic vision• Relatively large brain• Only one (or two) offspring at a time• Long maturation of the young• High degree of dependence on social life and

learning• Reproductive system

TYPES• Prosimians: pre-monkey ; depend more on smell for

information; have mobile ears; whiskers, longer snouts and fixed facial expressions.

• Anthropoids: have rounded braincases; reduced,

nonmobile outer ears; and relatively small, flat faces instead of muzzles; have highly dextrous hands.

• Lesser Apes (Hylobates) : Gibbons and Siamangs

• Great Apes (Pongids) : Orangutans, Gorillas, and Chimpanzees

• Sexual dimorphism – males are larger, have longer canines, more aggressive than females• Capable of surviving in arid and seasonal• Ischial callous on their bottoms

Hominoids vs other monkeys• Longer brains especially the cerebral cortex• Fairly long arms, broad trunks, no tail• Hands are longer than other primates• More bipedal• Dentition is unique, molars are flat and rounded• Gorilla and Chimpanzee have proteins and DNA

similar to humans; use tools; ability to learn sign language

• Diverged from a common ancestor. 5-6 MYA

Humans• Bipedal • Human brain, particularly the cerebral cortex, is the

largest and most complex• Human females may engage in sexual intercourse at any

time throughout the year • Human offspring has a proportionately longer

dependency stage• Human behavior is learned and culturally patterned.

(spoken, symbolic language and the use of tools to make other tools)

• Humans have a division of labor in food-getting and food sharing in adulthood.

Human features related to Bipedalism

• Tool making• Enlargement of the brain• Prolonged period of infant dependency• Sexual division of labor• Food sharing

HUMAN ANCESTRYAustralopithecines

Homo HabilisHomo ErectusHomo Sapiens

Homo Sapiens Sapiens

AUSTRALOPITHECINES• the 1st man-apes of Africa; 4.5 million yrs.ago• adapted to light woodland or savannah living• with herbivorous dentition; food-crushing molar teeth.• almost fully bipedal but probably retained an acrobatic nimbleness

in tree climbing • many were small and very strong for their size.• brain size: 300-500 cm

• Raymond Dart’s “Taung baby” (A. Africanus) possibly the missing link. 1st fossil hominid discovery South Africa in 1924. Relatively large brain size. Teeth were of human type. Foramen magnum – opening at the buck of the skull thru which the spinal cord emerges, was below the brain case

• Fossil “Lucy” (A.Afarensis). by Tim White and Don Johanson in 1974 in Ethiopia; seen to be a hominid, since the knee and pelvis were characteristically human.

HOMO HABILIS• The making of human kind

• Olduvai tools : HH crosses the threshold from man-apes to humans..tool-making

• Expansion of brain size that allows the development of characteristically human intellectual, linguistic and social attributes and finer manipulative skills. The process of becoming human in a biological and social sense is called homonisation.

• Habilis means “handy” or “dextrous”; label by Louis Leakey in 1964 to the hominid remains associated with the earliest tools at Olduvai.

• Brain size: 500-850 cm

• Lighter jaw; decrease in incisor size• Fossils in Eastern Africa

HOMO ERECTUS• Tools, Hunting , Fire

• Hairless, erect posture, smaller face, teeth & jaw due to cultural innovations: discovery of fire & Acheulian tool)

• Tool makers and users; e.g. Acheulian hand axe ( East Africa and Israel; 1.6 Ma;

• Turkana boy – oldest and most complete skeleton of a single early human; West Turkana, Kenya; 1984; skeletally fully modern, bigger than HH

• Larger brain size – early Java man 600-800 cm; late H. erectus volumes were as much as 1250 cm.

• Represents a steady change in becoming mentally, socially and culturally more human. (Evidence of hunting and gathering; travelling & carrying would put a pressure on bipedalism

HOMO SAPIENS• Multi-regional hypothesis: H.sapiens had risen all over

the world with perhaps gene flow linking one group to another and conserving the genetic integrity of a specie. Fitted with the racial ideas of five ancient races (Bushmen, Negroids, Caucasians, Mongoloids, and Australoids).

• H. Sapiens Neandertahalensis: Neander River in Germany. They were upright and un-apelike; stocky and muscular; enlarged pelvis

• Mousterian tool kit (refinement of an earlier Levalloisian method)

HOMO SAPIENS SAPIENS• Type specimen is Cro-Magnon man, dated at 30Ka, from

France; taller and finer-boned than Neanderthals; the last European cavemen had impressive cave art at places in France and Spain; ritual burial sites reveal the devt. of jewelry, colored beads, and ivory bracelets.

• Cultural take-off (Art, Language, Hunting, etc.)

• As culture picked up and passed on ideas, the human species’ power over its envt. increased beyond the normal energy and physical limits of a hominid, setting the scene for the dawn of agriculture and the earliest civilization.

What happened to the Neanderthals?• Neanderthals and modern humans co-

existed in Europe and Middle east for 20k or 60k yrs.

• Possible causes:• Interbreeding• Genocide• Extinction

Theories about the Origins of Modern Humans• Single Origin Theory: modern humans emerged in

Africa and spread to other parts of the world• Multiregional Theory: modern humans emerged

into various parts of the world, becoming the varieties of humans today• Fitted with racial ideas of five ancient races

(Bushmen, Negroids, Caucasians, Mongoloids and Australoids)

• Intermediate: There may have been some population replacement local continuous evolution and interbreeding

Physical Variation• Looks at how and why population

physically resembles or vary from each other

• 1400’s concept of race developed and became fixed in the 1700’s

• Common classification: white, black, yellow race

• Concept of race has greatly influenced humanity and even the thoughts of 10th century’s most vicious criminal• Hitler’s Aryan race• Apartheid in S. Africa thrived due to the belief that blacks

belonged to an inferior race• European expansion was based on the “white man’s

burden” percept. The early phrase of colonialism thus coincided with the rise of racism

• Many beliefs about race, however are mythical in nature: Negroid (dark, tightly curled black hair), Australian Aborigines (dark wavy and sometimes blond hair)

• Race is more of a social cultural construct than a biological fact, superior or inferior culture to skin color but not hair color

Processes in Human Variation• Adaptation: genetic change that gives it carriers a better chance

of survival and reproduction than those without the genetic chance to live in the same environment

• Acclimatization: involves physiological adjustments in individuals to environmental conditions• Tanning – an acclimatization among white skinned people

when exposed to high levels of solar radiation is related to adaptation

• Influence of the cultural environment: culture can alter the environment• Inca, Andean society practice head binding to create physical

variation• Hebrew, Abraham and all males had to be circumcised as a

sign of covenant between them