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Complete Human Biology, Behavior, and Evolution Study guide: Part 3 (90% on final)

33 Pages

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CAS AN 102

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Lecture 25 How are fossils formed? ★ an animal dies and eventually just bones remain ★ trampling, tumbling of bones may occur ★ covered by sediment ○ sand, silt, mud carried by water ○ dust or volcanic rock ★ minerals in water or soil replace bone mineral turning bone to stone (petrification) ★ later erosion uncovers fossil so we can discover it Which bones get fossilized? ★ fossils are rare and represent a small fraction of past life ★ have to have unique conditions of preservation, volcano, flood ★ teeth and jaws more likely to be recovered taphonomy: the study of what happens to the remains of an animal from the time of death to time of discovery ➔ did damage on bones occur before or after death? ➔ what happened after the animal died? did scavengers have an effect on bone? ➔ did bones get moved by water, or are the bones found where the animal died? ➔ were cut marks on animal bones due to humans or animals? stratigraphy: the study of the order of rock layers and the sequence of events they reflect ➔ sedimentary rocks are formed layer by layer ➔ over time these layers pile up on each other ➔ bottom layers are older than top layers ➔ geological processes can deform once horizontal layers James Hutton ★ uniformitarianism - geological processes in the past same as those in present Charles Lyell ★ synthesized Principles of Geology Principles of Stratigraphy ★ Principle of Original Horizontality ○ all earth’s layers are laid down parallel to earth’s gravitational field ★ Principle of Superposition ○ older layers at bottom, younger layers at top ★ Principle of Cross-Cutting ○ geological features that cut through existing layers must be newer ★ Principle of Faunal Succession ○ the earth’s animals are laid down in predictable sequences of strata that contain certain types of fauna, showing changes through time Dating Techniques ★ relative: uses stratigraphy to establish relative age ○ lithostratigraphy ■ match up rock units from different areas to get relative ages ○ biostratigraphy ■ use biological organisms with a good fossil record to get relative age ○ fluorine and Piltdown Hoax ■ 1908 - fossil found in England ■ two different bones ★ chronometric: uses an absolute clock to provide an age estimate ○ radiometric dating ■ extra neutron in carbon 14 makes it unstable, it wants to get rid of that extra neutron ■ radioactive atoms in the isotope change into stable atoms in the isotope ■ half life: the time it takes to reduce number of radioactive atoms by 50% ■ we can measure the ratio of radioactive to stable atoms to date ○ potassium-argon dating ■ potassium-argon has a very long half-life so can be used to date very old things such as volcanic rock ■ because fossil hominids are often found between layers of volcanic rock we can use this method ■ have to use a rock sample for potassium and one for argon gas ○ argon-argon dating ■ uses just argon and smaller samples ○ carbon 14 dating ■ when an animal dies, its bones contain a certain amount of 14c absorbed from the air and its food ■ after 5730 years half the original 14c becomes 12c ■ after 11460 years ¾ of the original 14c becomes 12c ■ after 17190 years ⅞ of the original 14c becomes 12c ★ calibrated relative: compares a relative technique to absolute time scale Climate Change ★ habitat analysis ○ c3 plants - trees and shrubs - make a 3 carbon compound during photosynthesis ○ c4 plants - tropical grasses - make a 4 carbon compound ○ look at ratios of these carbons in teeth to tell what animal ate and habitat ★ changes in oxygen measured in deep sea cores tells us of changes in temp and sea levels ★ continental drift ○ the position of continents plays an important role in evolution of species ■ oceans serve as barriers that isolate certain species (facilitating genetic drift, allopatric speciation) ○ continental drift is an important engine of climate change ★ the climate in which earliest primates evolved was different from that in which early humans evolved (warmer) Lecture 26 ★ flowering plants evolved at the end of the cretaceous period, led to increased insect evolution and abundance ★ asteroid hits earth - dinosaurs go extinct, small insect-eating mammals survive and flourish ★ Plesiadapiforms ○ primate-like mammals ○ had cheek teeth like those of modern primates ○ but their anterior teeth are too specialized for primate ancestors ○ didn’t have postorbital bar ○ claws ○ mostly arboreal ○ small to medium size ○ NA, Europe, China ★ Purgatorius ○ early plesiadapiform ○ less specialized, generalized teeth ○ could have been primate ancestor ○ from late cretaceous period, Montana ★ earth become warmer in eocene epoch - primates ★ Adapids and Omomyids ○ larger brains ○ eye sockets face forwards ○ complete postorbital bar ○ opposable big toe ○ nails not claws ★ Adapids ○ diurnal ○ lemur-like skulls (no toothcomb) ○ strepsirrhines? ○ ate leaves ○ relied more on smell ○ premolar and molar shearing crests ★ Omomyids ○ mainly nocturnal ○ tarsier ish? ○ haplorhines? ○ ate insects and fruit ○ shorter snout ○ small species - sharp pointed molar cusps ○ large species - flat molar teeth ★ Anthropoids ○ earth becomes cooler and dryer at end of Eocene ○ led to faunal turnover called Grande Coupure ○ adapids and omomyids go extinct ○ monkeys evolve in oligocene (58-40 mya) ○ change in climate led to new niches and new foods to exploit ○ bigger bodies ○ mandible fused ○ orbits fully enclosed ○ enabled them to chew a tougher diet ■ more force with fused mandible ■ more protection of eyes during chewing allows you to see better and avoid predators ○ Eosimias ■ early anthropoids or unusual tarsier? ■ late eocene of China (45-32 mya) ■ tiny animals, sharp cusped insect eating teeth and omomyid type ear regions ■ anthropoid-like foot bones ★ Fayum Depression ○ Egypt ○ Parapithecidae ■ first occur in early Oligocene ■ ■ ring-like ear bone ■ could be ancestor to NW monkeys ○ Oligopithecidae ■ found in late Eocene ■ small monkeys with sharp-cusped teeth and big closed orbits ■ ring-like ear bone ■ ■ earliest catarrhines? ○ Propliopithecidae ■ late oligocene ■ ■ ring-like ear bone ■ ape-like molars ■ ancestral to all catarrhines ■ first definite catarrhines ○ Victoriapithecus ■ ate hard fruits and nuts ■ small ■ probably ancestral to all OW monkeys ★ all major platyrrhine groups present in SAby the miocene ★ Primate Evolution ○ hominoids evolved a different anatomy than earlier primates ○ more suited to a suspensory lifestyle ○ relatively short trunks ○ broad chests ○ long arms ○ flexible shoulder joints ○ no tails ○ skull and teeth of middle miocene apes also show that they had a more robust and fibrous diet than the earlier proconsulids ○ related to climate change, drier, more seasonal environment produced tougher vegetation and harder seeds ○ many fossil apes and few fossil OW monkeys from the early/middle miocene ○ today we see few living apes and many living OW monkeys ★ Miocene fossil record ○ apes appear at the end of the oligocene and radiate in the miocene ○ one big change: the socket of the shoulder joint faces ventrally (toward the belly) in the quadrupeds but more sideways in apes and humans ○ African forms - 23-14 mya ○ European forms - 16-11 mya ○ Asian forms - 16-7 mya ■ Proconsul ● African form ● multiple species ● lived in rain-forest environment ● sharing same features with living humans (no tail) ● arboreal quadrupeds ■ Oreopithecus & Dryopithecus ● European forms ● Dryopithecus probably an arboreal brachiator ● Oreopithecus may have lived in a swampy habitat ■ Sivapithecus ● Asian form ● related but not ancestral to modern orangutans ■ Khoratpithecus ● Asian form ● may be orangutan ancestor ■ Gigantopithecus ● a giant Chinese ape from middle miocene to 1 mya Lecture 27 ★ Bipedalism is the primary diagnostic trait that defines all hominids ★ footprints in Africa 3 mya - human ★ BipedalAdaptation - major anatomical innovation, involves reorganization of several anatomical regions; must have provided a fitness advantage ○ Pelvis ■ the pelvis is composed of three elements ● 2 os coxae ○ each os coxa is composed of an ilium, ischium, pubis ● 1 sacrum ■ flatter, broader iliia ■ shorter pubic bones ■ more bowl-shaped pelvis ■ gluteus maximus (along with hamstrings) helps move thigh backward during walking ■ the gluteus maximus also helps stabilize our trunk ■ abductor muscles keep the body erect during walking ■ when you lift one foot, the deep gluteal muscles on the other side contract to keep the unsupported side of the pelvis from dropping ○ Femur ■ longer limb overall ■ human femur is angled - bicondylar angle or carrying angle - helps to position the lower leg directly under the body ○ Vertebrae ■ humans have distinct spinal curves to keep weight centered above pelvis ■ lower (lumbar) vertebrae are very large in humans (in order to support weight of trunk, arms, head) ■ pregnancy - increased strain on spine ● to compensate for bipedal pregnancy, human females have evolved: ○ more spinal curvature ○ reinforcement of lumbar vertebrae ○ Foot ■ the human foot has a longitudinal arch that helps to absorb shock and add spring to each step ■ humans have transverse arch formed by tarsal bones of foot ■ humans also have an adducted hallux that helps us balance ■ toe bones are short, broad, and stout, especially big toe ■ toes less curved ○ Skull Base ■ in humans, the head is centered on the spine ■ the spinal cord leaves through a downward facing foramen magnum ■ in quadrupeds, the foramen magnum faces posteriorly and is farther back ★ Scenarios of Human Evolution ○ Carrying Objects ■ prime mover: need to carry objects, food, children, tools ■ evidencet: bipedalism would have given us the advantage of being able to carry things ■ assumptions: was this enough of a selective force? ○ Long Distance Walking Efficiency ■ prime mover: need to cover large distances in search of food ■ evidence: climate change - led to greater distance between food; more efficient than knuckle walking ■ assumptions: assumes habitat changed and needed to cover long distance for food ■ bipedal humans use much less energy than bipedal apes ○ Thermoregulation ■ prime mover: need to dissipate heat on savannah ■ evidence: bipeds dissipate heat faster than quadrupeds because stand farther away from ground ■ assumptions: assumes bipedalism evolved on savannah, would this have been enough of a selective pressure to change locomotion? ○ Visual Surveillance ■ prime mover: need to see over grassland to look for foods/scan for predators ■ evidence: not much ■ assumptions: assumes bipedalism evolved on savannah; would this have been enough of a selective pressure to change locomotion? why not just stand up? ○ Bipedalism in Trees ■ prime mover: more efficient locomotion and/or feeding posture in trees ■ evidence: gibbons and orangutans stand and walk bipedally in trees ■ assumptions: assumes change in tree structure of hominin ancestor that selected for change in arboreal locomotion/feeding posture ○ Seed and Nut Gathering ■ prime mover: efficiency for feeding on seeds ■ evidence: baboons squat and shuffle when eating seeds on savannah; evolved postural changes in pelvis as a pre-adaptation to bipedalism ■ assumptions: assumes evolved on savannah; were we eating seeds? ○ Reaching Fruit ■ prime mover: need to gather hard to reach food from trees ■ evidence: evolved standing first as a feeding posture ■ assumptions: why would it lead to bipedal walking? ○ Bipedal Wading ■ prime mover: bipedal wading to obtain fallback foods ■ evidence: baboons, all apes, and humans wade to get fallback foods in delta areas, increasing evidence that these areas were an important part of landscape for early hominids; obtaining tubers and rhizomes that also match isotopic evidence of early ○ Avoidance of Predation ■ prime mover: need to move quickly to avoid being eaten ■ evidence: evolved bipedalism so could quickly move across open areas of savannah ■ assumptions: assumes bipedalism evolved in savannah, enough of a selective pressure? ○ Hunting ■ prime mover: need to stand and walk upright for hunting ■ evidence: bipedalism allows you to carry weapons and hunt more efficiently ■ assumptions: hunting seems to have evolved after bipedalism ○ Male Display ■ prime mover: need to look more imposing - threat to other males ■ evidence: chimps and gorillas stand upright during displays; leads to increased dominances and more mating opportunities ■ assumptions: why lead to bipedal walking? ○ Male Provisioning ■ prime mover: need to provision dependent offspring ■ evidence: as human infants more dependent mothers need help provisioning; walking lets you carry food back to mother and baby ■ assumptions: no evidence of monogamy with bipedalism; assumes high paternity confidence; assumes food was a type that can obtain extra to provision others; others can provision, not just males; in most foragers women provide more than 50% of calories ★ may have started off as a postural change as feeding niche changed ★ bipedal walking selected for because more efficient as needed to travel longer distances as food sources became more dispersed ★ led to secondary benefits: better for thermoregulation, could start carrying things Lecture 28 What makes a fossil a hominin? ★ paleoanthropologists use bipedalism as a diagnostic trait that defines all hominids - a bipedal member of the evolutionary lineage leading to modern humans ★ parabolic dental arcade (vs. a U shaped in apes with parallel tooth rows) ★ less prognathism ★ lose cp3 complex - sectoral premolar complex ○ p3 lower first premolar is sectoral (bladelike) which hones (sharpens) the back of upper canine; the upper canine fits into diastema (space) in lower jaw ★ thicker enamel ★ eventually develop larger brains - brain size unit of measurement is cc - cranial capacity ★ split from chimpanzees 6-7 mya Ardipithecines: Earliest Hominins? ★ Sahelanthropus tchadensis ○ skull found in Chad in 2001 by Brunet ○ 6-7 mya? ○ relatively short and flat face ○ similarities in teeth ○ somewhat anterior foramen magnum ○ large brow ridges, chimp-sized skull and brain, sagittal crest ○ 320-380 cc ★ Orrorin tugenensis ○ fragmentary remains from several individuals found in Kenya in 2001 ○ 6 mya ○ femur shows evidence of bipedality ○ lived a more forested environment than expected for early hominins ○ teeth show chimp-like features - honing complex: upper canine rubs against lower first premolar - sharpening function ★ Ardipithecus ramidus &Ardipithecus kadabba ○ Ethiopia, 1990s ○ A. ramidus - 4.4 mya; A. kadabba - 5.2-5.8 mya ○ anterior foramen magnum ○ toe bones suggest bipedality ○ canine teeth are more primitive ○ thinner enamel on molars ○ more flexible hand than what a chimp possess - not a knuckle-walker ○ bipedal on ground - quadrupedal in trees ○ doesn’t show adaptations for brachiating Australopithecines ★ beginning around 4 mya (pliocene epoch) hominids began to diversify ★ gracile and robust ★ 4.2-1.2 mya ★ mix of bipedal locomotion and ape-like features ★ small-brained creatures with lots of sexual dimorphism in body mass and a little in canine size ★ some species had specialized dietary adaptations ★ small incisors/canines relative to body size ★ herbivores and possibly some meat eating ★ East and South Africa - first discovered - (southern ape) Gracile & Robust forms - features are separated by dental and jaw morphology (dietary adapt.) Gracile Forms Robust Forms Australopithecus anamensis (EastAfrica) Australopithecus aethiopicus (EastAfrica) ★ found by Meave Leakey at Lake ★ 2.6 mya Turkana in Kenya ★ Ethiopia ★ 4.3-3.9 mya ★ maybe ancestral to later robust forms ★ evidence of bipedalism based on ★ 410 cc interpretation of bicondylar angle ★ prognathic face (like afarensis) ★ orangutan-like snout ★ large anterior teeth ★ (some say this is ardipithecus) - ★ sagittal crest transition between the two? ★ large molar teeth ★ dish-shaped face ★ flared zygomatics ★ “the black skull” Australopithecus afarensis (EastAfrica) Australopithecus robustus (SouthAfrica) ★ found in east Africa at Laetoli ★ 2-1.5 mya (Tanzania) and Hadar (Ethiopia) ★ sagittal crest and other heavy chewing ★ 3.9-2.9 mya adaptations ★ bipedal but adaptations for climbing ★ 500-530 cc ★ 350-500cc ★ 70-90 lbs ★ mix of ape-like and human-like traits ★ hand/feet more modern ★ sexually dimorphic in body size ★ “Lucy” - 3.2 mya ★ subnasal prognathism (compared to modern humans - orthognathic) ★ diastema like chimps ★ U-shaped dental arcade ★ canines less sexually dimorphic than chimps, more than humans ★ incipient cusp on premolar ★ ilium is flared - more human-like ★ 3.5 myo footprints - Laetoli - striding gait - small bipeds Australopithecus africanus (South Africa) Australopithecus boisei (EastAfrica) ★ 3.3-2 mya ★ 2.3-1.2 mya ★ firstAustralopithecus discovered ★ Mary Leakey, Olduvai Gorge, 1959 (Taung child, 3 yo) ★ sagittal crest and other heavy chewing ★ Raymond Dart recognized it adaptations ★ evidence for bipedalism, canine ★ 475-545 cc reduction, slightly expanded brain size ★ very sexually dimorphic in body size ★ faster maturation than modern humans ★ extreme dish-shaped face (ape-like) ★ hyper-robust ★ foramen magnum anterior ★ face a little flatter, canines more reduced ★ some climbing adaptations (divergent big toe) Australopithecus ghari (EastAfrica) Kenyanthropus platyops (EastAfrica) ★ 2.5 mya ★ 3.5 mya ★ Tim White, Ethiopia, 1999 ★ Meave Leakey, Kenya, 1999 ★ bigger cheek teeth and anterior teeth ★ 400-500 cc ★ proportionally longer lower limb ★ flatter, less prognathic face bones ★ no definitive postcranial fossils ★ associated with antelope bones with ★ relationship toAustralopithecines not cut marks and primitive tools clear - ancestor to homo? Australopithecus sediba (SouthAfrica) Robust forms ★ 1.98-1.78 mya ★ larger cheek teeth/very reduced ★ South Africa lime cave site (melapa) anterior teeth ★ 420cc ★ highly derived chewing machines ★ small molars and canines ★ larger attachment sites for muscles ★ brain asymmetry involved in chewing ★ nose ★ sagittal crest ★ conical thorax, upward tilted scapula ★ broad, flaring cheek bones and ★ long arms postorbital constriction to ★ ape-like foot features accommodate size of temporalis ★ hand digits not curved muscle ★ long thumb ★ molarized pre-molars ★ pelvis - bowl shaped ★ the attachment area of the temporalis muscle was larger in robust Australopithecine forms than in modern humans ★ sagittal crest for attachment of temporalis muscle ★ masseter muscle - moved forward over teeth - attaches to zygomatic - moved forward ★ dish shaped Bipedalism came first ★ early theories of human evolution speculated that humans developed large brains early in our lineage ★ people wanted large brains to have evolved before anything else because they thought our intellect separated us from lower animals ★ although the firstAustralopithecus skull was discovered in 1924, people ignored the evidence pointing to small-brained ancestors ★ instead, people latched onto finds such as Piltdown Man Lecture 29 Reconstructing Behavior ★ paleoanthropologists use fossils and associated artifacts to make inferences about early hominin behavior ★ interpreting fossils based on an analog - living species that we use as a model ★ we can analyze behaviors found in both chimps and humans: these are likely to be found in the common ancestor of humans and chimps ★ behavioral features ○ culture ■ evidence that chimps possess cultural attributes ○ tool-use ■ a lot of evidence for tool use (manipulating a natural object to achieve a desired goal) ■ associated with remains of butchered animals ■ wear patterns on animal bones - may have used as digging sticks ○ warfare ■ documented in chimps and humans ■ male chimps regularly patrol boundaries of their home regions ○ hunting ■ chimps regularly hunt vertebrates ■ hunting appears to be a cooperative effort Australopithecus was a human biped but may not have walked like us ➔ differences in postcrania: ◆ pelvic shape ◆ pelvic width ◆ angle of knee ◆ proximal femur - smaller head, longer neck ➔ retained adaptations for climbing ◆ long, curved finger and toe bones ◆ small vertebral bodies (not as stable for walking) ◆ somewhat ape-like scapula ➔ compromised biped? ◆ retained some adaptations for climbing, so not as good of a walker ➔ walked just like us? Social Structure ★ body-size dimorphism conspicuous in many catarrhines ★ a lot of sexual dimorphism ★ large differences in body mass and height between male and femaleAustralopithecines ★ high body size dimorphism, low canine dimorphism ★ implies body size dimorphism and canine size dimorphism no longer linked in hominids ★ stopped fighting with mouths - body now sexually dimorphic, especially upper body ★ because of high sexual dimorphism australopithecines were likely living in one-male or multi-male groups ★ were not monogamous or pair-bonded ★ degree of dimorphism and social structure varied likely as result of diet Birth ★ encephalization and bipedalism combine to make parturition a difficult and laborious process for human females ★ constraints of human pelvis ○ shortening of distance between sacroiliac joint and acetabulum (hip joint) ○ sacrum is opposite pubic symphysis ○ pelvic inlet is widest in transverse dimension ○ pelvic outlet is widest sagittally ○ baby must rotate 45-90 degrees to exist pelvis ★ human birth ○ human fetal head must enter the birth canal with its head in the oblique or transverse plane (sideways) ○ once head has passed pelvic inlet, rotates to align with sagittal plane so longest dimension of head is aligned with widest dimension of midpelvis ○ once the head rotates, the shoulders remain in the oblique or transverse position ○ neck is twisted ○ head emerges ○ shoulders rotate sideways ○ head rotates sideways outside of pelvis ○ top shoulder emerges under pubic symphysis ○ bottom shoulder emerges ○ doula effect - birth support - supported mothers had fewer problems and shorter labors ○ Australopithecines - difficult births (less difficult than now) Lecture 30 ★ 2.5 mya ★ environment became cooler, dryer, and more variable ★ oxygen enrichment ★ variability selection - when organisms encounter periodic remodeling of landscape and resources some populations respond to these shifting selective conditions by favoring genes and phenotypes that build adaptive versatility ○ locomotor system designed to allow a wide repertoire of movement ○ dental structure or foraging strategy that enhances a shift to newly available foods ○ large brain that is effective in processing external data and generating complex cognitive responses ○ species-specific social behaviors from which broad range of mating-systems or grouping could manifest ★ Homo habilis ○ oldest known species of the genus ○ EastAfrica ○ fossils date to 2.3-1.4 mya (tools - 2.5 mya) ○ Olduvai Gorge ■ Louis Leakey found the first Homo habilis fossil here ■ A. boisei ■ first site where hominin species are found in association ○ no sagittal crest, smaller teeth, found in close association with tools ○ skull more rounded ○ 600-700 cc - larger brain thanAustralopithecine ○ less prognathic ○ smaller molars ○ parabolic dental arcade ○ less postorbital constriction ○ Koobi Fora, Kenya - solidified new genus and species (Richard Leakey) ○ more efficient biped - longer legs, robust heel bone ○ modern biped gait, fully terrestrial ○ increased manual dexterity - long, strong thumb; short, straight fingers; broader fingertips ○ lived in savannah and woodlands ○ primarily vegetarian, somewhat more mixed diet ○ likely ate meat ○ Oldowan tools ■ Olduvai Gorge, Louis Leakey, 1930s ■ 2.5 mya ■ haphazard in design, made from locally available materials ■ core - stone source material, shows evidence of flake removal (small fragments taken from core) ■ hammerstones - use to strike core or bones? ■ presence of tools tied into the Man the Hunter paradigm - however, meat eating - association with animal bones with stone tools ● marks on bones indicate processing with tools ● sometimes before carnivores (hunting) ● sometimes after carnivores (scavenging) ○ hunting, passive scavenging, confrontational scavenging? ○ diet ■ stone tools preserved, likely still ate primarily vegetarian diet, incorporation of meat ★ Homo erectus ○ 1.8 mya ○ associated with more climatic variability ○ bigger, bigger brain ○ found outside ofAfrica ○ more advanced tools ○ Eugene DuBois, 1891 - Java ○ skullcap and femur ○ 1930s, Davidson, Black, Franz Weidenreich, Pei Wenzhong - Zhoukoudian ○ Lake Turkana, 1984 - Turkana Boy ■ 1.6 mya ■ 11-12 when he died ■ 5’3’’, likely to be 6’1’’ ■ long, linear body shape ■ 900cc ○ 750-1250cc ○ more encephalized ○ large brow ridges, low forehead, broad at skull base, occipital torus, thick cranial bones ○ switch to higher quality diet - big increase in brain size ○ dentition ■ shovel shaped incisors ■ much smaller molars ■ facial shortening ○ as tall as modern humans ○ more sexually dimorphic than modern humans ○ thicker long bones Lecture 31 ★ Acheulian tools ○ larger and more symmetrical than Oldowan tools ○ tear dropped shaped hand axes common: standardized forms ○ flaked on all sides = biface (includes hand axes and cleavers) ○ design consistent over 1.2 mil years ○ use ■ hold a sharp edge for longer ■ greater length for working edge ■ convenient size - less fatigue ■ assumed used to butcher large game ■ could be used for scraping plant material ■ digging roots, tubers, holes with small game? ○ rare or absent in EastAsia ■ didn’t need them? bamboo forests may have provided materials necessary for making tools ■ could be from earlier wave of Homo erectus that leftAfrica before Acheulean tools were invented ★ Diet ○ evidence that dramatic shift in dietary quality due to cooking of meat and vegetables ○ likely ate largely plant-based diet like apes and modern foragers ○ incorporated more meat in diet ○ evidence of butchering large game - maybe obtained through aggressive scavenging? ○ likely ate smaller animals as well ★ World Traveler ○ 1999 - Dmanisi, Republic of Georgia ■ 1.7 - 1.8 mya ■ Oldowan tools, migrated out ofAfrica with tool-making skills ■ H. georgicus? ■ earliest Homo erectus to leave Africa ■ very small skulls and brains - 630-800cc ■ within lowest range of other H. erectus ■ some skull features like even earlier Homo ■ 4’5’’ ■ were there two waves with the second wave coming from a bigger and bigger brained H. erectus? ■ one individual died with just 1 tooth left ■ must have had to have been fed soft food ■ cooking and fire? ■ Oldowan tools ★ Archaic Hominin Species ○ Homo heidelbergensis ■ 800-130 kya ■ pre-modern humans or archaic Homo ■ tricky to taxonomically classify ■ 1250cc ■ taller skull than earlier hominins ■ less protruding face ■ thinner cranial bones ■ no occipital torus ■ large, rounded brow ridge (forms arches) ■ larger brain ■ taller vault with more parallel sides (less rounded cranial vault) ■ wide nasal aperture ■ no canine fossa ■ Africa ● Kabwe, Zambia (Broken Hill) ● 300-130 kya ● 1280cc ● gracile postcrania ● defleshing? ■ Europe ● Steinheim, Germany ● 250 kya ● 1100cc ● wide parietal breadth ● thin cranial vault ■ Asia ● Dali, China ● 230-180 kya ● 1120cc ■ tools ● Acheulean hand axe ● 300 kya - Levallois technique - large symmetrical flakes ● hafted stone tools (attached to sticks) ● early wooden spears - coal mine in Germany ● 380-400 kya ■ Pleistocene epoch ■ controlled and used fire ■ built shelters and structures ■ exploited many different food sources ★ Modern Homo sapiens ○ Africa - 160 kya ○ 100-50 kya - spread throughout world ○ longer limbs ○ skeletons are less robust ○ vertical forehead ○ small face with protruding chin ○ less robust postcranial skeleton ○ small brow ridges ○ small incisors ○ pyramidal mastoid process ○ definite chin Lecture 32 ★ 1856 - Neander Valley, Germany - Homo neanderthalensis - original caveman? ○ distributed across the western part of Eurasia ○ found mostly between 130-30 kya ○ own species or subspecies ○ misperception of stooping, brutish individuals ■ a flawed reconstruction of one of the earlier complete Neanderthal skeletons discovered ■ an oversight of the fact that the skeleton had severe, debilitating arthritis ○ short, robust, heavily muscled ○ barrel-chested ○ different hairstyle ○ anatomy points to cold-adapted species ■ large nasal opening and barrel chest allow for better warming of air during respiration ■ short, robust stature conserves heat ■ limb proportions of neandertals resemble those of modern people living above the arctic circle ○ midfacial projection ○ 1245-1740cc ○ maximum cranial breadth at different positions on vault (middle) ○ side walls parallel in humans ○ teeth ■ very large, worn anterior teeth ■ shovel shaped incisors ■ small posterior teeth ■ back premolars have extra cusps ■ molars have taurodont roots ● expanded pulp cavity ● fused roots ● can sustain more wear ○ several partial skeletons recovered in site in NE Iraq ■ Kebara Cave, Israel, 60 kya ● one male, 30-45, 5’7’’, 1600cc, paralyzed right arm ● survived despite injuries - compassion and community care ■ deliberately buried their dead? ● body is moved into fetal position ● animal bones and stones buried along
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