Story of the Human Body Notes PDF

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Daniel E Lieberman Story of the Human Body Notes Chapters 1,2,3,4,6. Anthropology 2 Monica Smith...

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4/2/18 Anthropology Reading Notes The Story of the Human Body Chapter 1: Introduction 

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Mystery monkey surviving in Florida, living off trash and escaping capture attempts o Used as political symbol of freedom o Makes us question where we belong, how we ought to live, etc What are human bodies adapted for o Aspects of natural selection  Variation  Genetic Heritability  Reproductive Success Adaptation o Increases chances of reproduction o Positive change to species over time o Lots of features of a species are not adaptations  Dimples As species evolve, they gain adaptations but also lose others o Humans lost climbing and running ability Mismatch Hypothesis o We have created an environment (physical and food) that we are not adapted for, and thus we are getting sick from it o Since we are a mass of adaptations over thousands of years, we have adaptations not only as hunter-gatherers, but as primates, farmers, etc. Human transitions o 1) apes transitioned to bipeds o 2) australopiths adapted to eating more than fruit o 3) 2 million years ago transition to human genus with larger brains and beginnings of hunter gatherers o 4) Hunter gatherers flourished, brains grew and bodies grew slower o 5) Modern humans with capacity for language, culture, and cooperation o 6) Agricultural Revolution o 7) Industrial Revolution

Chapter 2: Understanding Apes 

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Humans lost great agility and athletic ability when transitioning to bipeds o As we lost the ability to climb and move with great speed, we gained the use of our hands to create Human lineage links our last common ancestor (LCA) closer to chimps than to gorillas o Missing LCA is probably due to evolution in the African forests, where fossils are uncommon due to fast decomposition o Proposed split from gorillas 9 mya and from chimps 6 mya Early hominins found have many apelike features o Small brain cavity, large front teeth, long snouts o Some think they are still part of apes, but evidence (sometimes in analyzing neck features) tells us that they were most likely bipedal Differences in Bipedal Bodies o S-shaped spine  Allows for posture to be vertical  More vertebrae make for a second curve o Sideways-facing hips  Allows for stabilization while walking o Larger molars for crushing stems of plants o Feet are arched and toes can hyperextend o Early bipeds had thicker molars for crushing lower quality foods (chimps mainly eat fruit) Benefits and disadvantages of Bipedalism o Benefits  As climate changed to much cooler temperatures approximately 10 MYA, there were less trees and more open land  Bipedal walking is 4x more energy efficient  Can use hands to forage more efficiently o Disadvantages  Move much more slowly and less agile  Pregnancy is hindering Bipedalism is the source of humans, not an increase in size of brain o Advantages outweighed disadvantages  Early bipeds could still climb trees efficiently, but may have not been as fast as chimps

Chapter 3: Much Depends on Dinner 

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Australopiths o Relative proportions to chimps o Larger, flatter molars for grinding food  Climate still cooling, and fruit becoming much more scarce o Large toe more front than that of chimps, allowing for them to walk much further much easier  Slightly curved foot Fallback foods o Started digging for foods such as tubers  Underground storage organs (USOs) o Made for larger teeth for grinding  Au. Africanus had molars 50% bigger than chimps  Au. Boisei had molars twice the size o Made for very thick facial muscles and bones to anchor them Walking in search of food o Footprint evidence of a long stride like we have today  Pendulum walking with extended hips and knees o Chimps must bend legs in order to stay upright, wasting energy  Our walking is more efficient, using gravity to propel us forward o Use of simple tools like sticks and rocks to search for USOs Similarities between humans and australopiths o Toes in front with arched foot  Extended knees and hips while walking o Time spent on the ground mainly o Larger teeth than chimps for eating variety of food o Flexible lower back with a waist Evolution towards homo sapiens o Tendency to eat higher calorie, rich foods such as meat developed in the ice age starting 2.5 mya

Chapter 4: The First Hunter-Gatherers   

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Global cooling 3-2 mya (2 degrees Celcius ocean temp) sparked change Great rift valley formed in Africa, transforming it into dry landscape seen today o Formed rain shadow Hunting and gathering formed as an adaptation from the scarce food o Need cooperation and higher calorie dense foods o Use of tools developed Homo erectus evolved 1.9 mya in Africa (P 70) o Very humanlike o 40-70 kg, 4-6 ft o Entire population found in Georgia very far away o Hips flared out more to the sides than us o Females were on smaller end of human range o Faces tall and deep, with males especially had barlike browridge above their eyes o Brains intermediate in size Homo habilis (P 71) o “handy man”  Discovered in 1960  Thought to be the first maker of stone tools o Probably evolved 2.3 mya o Australopith body  Small with long arms and short legs, large cheek teeth  Larger brain with round skull o Modern hand Homo Rudolfensis o Larger brain than habilis, but had more australopith features o Probably part of Austroliphecus Homo erectus is the first ancestor we can characterize as significantly human o H Erectus mothers could not get enough calories for them and their young, most of the time 3 Parts of hunting and gathering o Gathering/hunting, cooperation, and food processing o Meat consumption began around 2.6 mya  Meat high in calories and vital nutrients  Origins of meat eating coincided with a division of labor in which females mostly gathered while males not only gathered but also hunted and scavenged. (P 74) o Food sharing also began, not only within families o Processing  Teeth poorly adapted to cutting meat  Don’t have the time like chimps to chew half a day and wait for digestion  First tools were Oldowan industry tools

Knock chips off another rock to make sharp knifelike tools Allows for meat and plants to be cut up, increasing digestion process Pounding meat and plants increases the amount of calories obtained from them  Food processing is as old as hunting and gathering H Erectus and Trekking o Longer legs (10-20% than australopiths)  Half the energy to walk o Higher arch, thicker leg bones, and larger leg joints o Trek in the sun when predators are not out  Larger surface area to cool, sweat  Only head and shoulders get direct sun  Protruding nose makes air travel further, humidifying it so that lungs don’t dry out Running o H Erectus and humans are very good distance runners o Used for gathering, but also mainly in hunting o Hunters needed to run, as their weapons were poor  Persistence hunting used, where hunter chases animal in heat until animal collapses of exhaustion o Sweat glands expanded from some areas of the body in monkeys to all over the human body  Humans lost hair and evolved sweat glands either during early homo or late Australopithecus o Legs developed for running  Takes same calories to rune at 7 or 10 minutes per mile  Gluteus maximus enlarged for stabilization  Achilles tendon acts as spring o Mechanisms to help head not jostle  Enlarged semicircular canals for balance  Nuchal ligament from shoulders to neck Tools o Developed 2.6 mya o Precision grip evident by 2 mya o Throwing necessary, and only humans can throw fast and accurately  Homo erectus has necessary anatomy: mobile waist, low and wide shoulders, horizontal shoulder joint, and highly extensible wrist (P 90) o H Erectus teeth shrunk down 25% to the size of humans Guts and brains o Humans have relatively small guts and large brains o Leslie Aiello and Peter Wheeler proposed that ratio is due to shift to higher quality diets o Brain size  Australopith: 400-550g  H Habilis: 500-700g   

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 H Erectus: 600-1000g Large brains for cooperation (strong theory of mind)

Chapter 5: Energy in the Ice Age 

Chapter 6: A Very Cultured Species 

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Hunter gatherers often hungry o Had to use cooperation to obtain food o After obtaining food, they could have social activities All humans can trace back to a population in Africa 300-200k years ago o Everyone descends from 14000 individuals o All non-Africans come from group of 3000 or so o Some have small amounts of Neanderthal and Denisovan blood due to interbreeding Modern humans show up in new areas o Europe – 40k ya o Asia – 60k ya o New Guinea and Australia – 40k ya o New World – 30-15k ya Large differences in head between Neanderthals and Humans o Humans have small faces with a chin o Neanderthals have large browridge o Human heads more spherical Middle Paleolithic o Had humans and Neanderthals, making simple tools o Made fires, cooked food, used spears  Killed mainly large animals o New tools like arrowheads, bone tools like harpoons o First symbolic art Upper Paleolithic (50k ya) o Toolmaking became easier  Mass manufacture long blades of stone from prism-shaped cores  Lots of bone tools like needles for clothing, lamps, fishhooks, flutes  Spear throwers and harpoons o Semi-permanent houses o Food developments  Small game hunting and fishing  Children and women could do it safely  Better food processing  Boiling and grinding o Art developments  Vast use of paint scenes, ornaments, and burials o Distinctive cultures  Neanderthals tried to copy human development, but lacked innovation and creativity, and thus they might have gone extinct Human versus Archaic brains

Temporal lobes bigger in humans  Increased perception (sight and smell)  Increased memory and language  Increased spirituality o Parietal lobes bigger in humans  Helps interpret and integrate sensory information  Gives us mental map  Interpret symbols, do math, and think abstractly o Prefrontal cortex maybe bigger  Helps cooperate with others and behave strategically (P 139)  Helps many aspects of hunting and cooperating in groups  Strong theory of mind  Control impulses o Longer time developing may allow for human brains to become more refined Human vocal tract is special o Brains are exceptionally skilled at rapidly and precisely controlling the movements of the tongue and other structures that modify its shape (P 142) o A retracted face gives us more acoustic variability o Humans are only species who risk choking from eating something large or imprecisely due to our airways Why Neanderthals went extinct (maybe) o Birth rate too high  If Neanderthal birth rate 1% higher in an area, Neanderthals would have gone extinct in less than 1000 years o Humans better at cooperating and changing  Environment changes us as we learn and change the environment  Causes cultural evolution Cultural buffering o Using the culture as a sense of environment to keep you alive o When deprived of technology, most of us would not survive (P 147) Changes in body from environment o Europeans got shorter over time to retain body heat o Africans stayed tall and lengthy to dump heat o Skin color obviously differed due to differing sunlight Adaptability comes from the brain o Our bodies are adapted for hunting and gathering, so is a transition to farming a mistake? o

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