ANTH 161 Exam 3

homo erectus migration

-1.8 mya: homo Erectus appears almost simultaneously in Africa and West/East Asia -evidence suggests that H. erectus probably evolved earlier than the earliest fossil we have/moved out fairly quickly -cooler climates led to the expansion of grasslands from Africa to asia (some animals followed, so humans followed them) -probably not one migration but rather a gradual flow of small bands of hominins over thousands of years -quickly moved to different climates/environments

Pakefield site, UK

-770kya -complex flake tools - likely part of the Achulean tradition -NO fossil remains

Neanderthal site: Umm el Tiel, Syria

-Mousterian point embedded in the neck of a wild donkey general evidence across Neanderthal sites: -predominantly upper leg bones (choicest cuts) -few carnivore gnaw marks, but lots of cut marks -breakage for bone marrow removal -focus on a single animal type (they have the ability to make that choice - this points to hunting, not scavenging)

H. erectus sites that provide evidence of hunting

-Olorgesaile, Kenya (900kya-700kya) -60 baboons -large, unmodified stones for throiwng -lots of Achulean tools for butchering -other sites in Spain provide evidence for hunting

Happisburgh site, UK

-UK -dated 990-780 kya -bifacial flaked stone tools -at the time, Britain was connected to Europe by a land bridge

Dmanisi, Georgia

-early H. erectus find with primitive tools (pre-Achulean, closer to Olduwan) -1.8-1.75 mya -brain size: 650-775 cc -small stature -good evidence of hunting and meat consumption - but no African game animals present

trends in human evolution: bipedal locomotion

-unique to hominins -appears early in the fossil record -is a true hominid-defining characteristic

H. sapiens encounter with neanderthals

-we definitely met and interbred with Neanderthals -Europeans/Asians have 1-2% Neanderthal DNA -people native to sub-Saharan Africa don't have any Neanderthal DNA, suggesting that their ancestors never encountered the neanderthals -sometimes, these encounters had a big impact (Eurasian version of STAT2 - viral response - is from Neanderthals), and the skin repair after sunburn is found in Asian populations from Neanderthals

human-chimpanzee last common ancestor

HC-LCA: unclear which (if any) of the fossil species that have been discovered represent the HC-LCA. the HC-LCA was likely far more similar to living apes than living humans, with sexually dimorphic canines, diet of fruit + leaves and quadrupedal locomotion

encephalization quotient

adult brain size relative to body size

hominins

humans and any species more closely related to us than chimps/bonobos. all bipedal primates that show up after the split with chimps/bonobos human ancestors are HOMININS. they exhibit bipedal locomotion (all forms of primates that habitually walk on two legs), large brains, and toolmaking abilities (tool MAKING, not using, is unique to hominins)

how are humans different from the living African great apes?

longer gestation periods, earlier weaning, slower post-natal maturation period, older age at first reproduction, and longer post-reproduction period

when did the first DIRECT ancestor of Homo sapiens appear?

about 2.5 mya in the Pleistocene epoch -when the first member of genus Homo emerged, there were at least three types of hominins living on the planet: -Paranthroupus robustus (South Africa) -P. boisei (East Africa) -A. sediba -genus Homo appears at the beginning of the Pleistocene epoch -most of human evolution took place during this epoch (this was the Ice Age, 2.5 mya - 12 kya) -series of glacial advances + retreats -increase in environmental variability producing complex + variable habitats -different adaptations among hominin populations to these new environments

which came first: bipedalism or big brains?

bipedalism

Mousterian tools

developed by the Neanderthals, made flakes using the Levallois technique of preparing cores (core prepared to a specific shape, 3-5 flakes can be taken off) -Mousterian process = Levallois technique + retouching of edges -increases variety -scrapers - useful for scraping hides (likely had other purposes as well) -name describes where the retouch happened (side scraper, end scraper, etc) -some Mousterian tools show impact on their bases (hafting) or impact (thrusting) -hafting = attaching a piece of stone to a stick to make a spear/projectile, sometimes stablized with natural gum or resin, wrapped with sinew or gut, Neanderthals may have been the first to make stone projectiles or thrusting spears

Paranthropus robustus

-2.2-1.5 mya -South Africa -brain = 520 cc sexual dimorphism present -average height: males - 3.75 ft and females - 3.2 ft -weight: males - 119 lbs and females - 88 lbs -sagittal crest larger in males -South African sites where scientists believe P. robustus used tools (isolated) -are they making or just finding/using tools? -bone tools found likely used to dig into termite mounds

Paranthropus aethiopicus

-2.7-2.5 mya -thought to be descended from A. afarensis -very small brain - 410 cc -most famous fossil is the "Black skull," found near Lake Turkana, Kenya -found by Mary Leakey -very robust face -huge molars -massive sagittal crest -what these features tell us: adapted to a very coarse diet, has huge chewing muscles + thicker enamel. this species is likely the direct ancestor to two or more Paranthropus species (robustus + boisei)

genus Paranthropus: subsistence

-2011 study studied the carbon in the enamel of teeth found from 22 Paranthropus species -it found that Paranthropus subsisted almost entirely on grasses, not solely on tubers and nuts as we previously believed

the "first family"

-Donald Johanson discovered 6-12 individuals (afarensis) who all died at the same time -cause of their death is unknown -adults and children, males and females -can study maturation, etc. -more recent A. afarensis infant found, could study baby teeth development -dentition studies of A. Afarensis children suggests slightly slower rates of maturation than modern apes (suggests a good period of dependency + emphasis on learning)

groups of early hominins from Africa (+ dates)

-Pre-Australopiths (about 7.0-4.4 mya) -Australopiths (4.2-1.2 mya) -Early Homo (2.0-1.4 mya) -early hominins may have lived throughout Africa, but we have preservation/exposure in East/South Africa

hominin evolution milestones

-by 6 mya: becoming bipedal -by 4 mya: mostly bipedal -by 2.6 mya: the dawn of technology (creation/use of stone tools) -by 800kya: control of fire -800-200kya: rapid increase in brain size -12kya: the turning point (herding, farming)

H. heidelbergensis + shelter

-first species we have evidence of shelter for -Terra Amata, France: dates to 400 kya -21 oval structures, 25-50' long -sapling posts with stone supports for central beams central hearths in each structure indicate control of fire -evidence of returning to the same place over the years

Oldowan tools

-found at Olduvai Gorge -associated with Homo habilis -pebbles with flakes struck off to make a sharp edge -about 1.8 mya -flake tools are when a flake is removed from a core, and the flake is used as a tool -hominins selected good rocks and brought them back to their site (this suggests planning and a good understanding of the properties of stone)

trends in human evolution: thicker tooth enamel

-humans tend to have thicker tooth enamel than apes, but both have much thicker enamel than other primates -BUT, thick tooth enamel was pretty widespread among Miocene apes, therefore it isn't a good way to distinguish fossil ancestors

Koobi Fora, Kenya

-in the 1980s, archaeologists discovered the first signs of an ancient fire -it is likely that our ancestors just took fire when it was there (like lightning, etc) -we aren't totally sure when/who first used fire -it is difficult to study fire because it is transient -ALSO, Wonderwerk cave (South Africa), more evidence for fire -Israel: Gesher Benot Y'aakov - phantom hearths

neanderthal adaptations to the cold

-large noses to warm + humidify cold and dry air -short and stocky bodies to conserve heat

homoplasis

a trait shared by different species due to shared functions rather than shared ancestry, i.e. it is not present in their last common ancestor

why is Homo Erectus dated terminology?

because we know that this species wasn't the first bipedal ancestor

why was cooking important in human evolution?

cooking was unquestionably a revolution in our dietary history - cooking makes food both physically and chemically easier to chew + digest, enabling the extraction of more energy from the same amount of food

tool technologies + associated species

olduwan - h. habilis acheulean - h. erectus Levallois - h. heidelberg mousterian - h. neanderthalensis

easiest way to determine bipedalism

the knee - an angled femur indicates bipedalism

expensive tissue hypothesis

hypothesis that energetic requirements of a large brain may have been offset by a reduction in the size of the liver/gastrointestinal tract. small guts need high quality food that is easy to digest, meat provided this food and supported the evolution of big brains

Australopithecus africanus

-3-2 mya -found in South Africa, Sterkfontain Quarry in 1924 (Taung Child) -cranial size around 440cc -sexually dimorphic (females about four feet, males about five feet) -moving bipedally with the ability to move in trees -body and brain like Australopithecus afarensis -reduced prognathism (flatter face) -no sagittal crest -is a "Gracile" Australopithecus - compared to other australopithecines (afarensis) - Africanus had a very slight build -diet was mostly mixed vegetables, possibly some meat -scavenging, possibly some hunting -more human-like cranium -very likely a descendant of A. afarensis -also likely on the path to the Homo genus -ancestral to Australopithecus sediba?

Raymond Dart

-discovered the Taung Child in 1924 in South Africa -he finds a fossil in a box from a limestone quarry -fossils of a young individual's face and a cast of the brain - known as the Taung Child -it was ape-like but with a few differences: teeth were more human like, and foramen magnum was underneath the skull, not at the back) -its species is Australopithecus africanus -b/c of the Piltdown Hoax, people didn't initially accept Dart's findings -

Homo erectus

-evolved around 1.9-1.8 mya in the Pleistocene -first known hominin to migrate out of Africa and populate Asia/Europe (moved Africa --> Asia --> Europe) -may be the earliest candidates for cooking (larger brain to body size, smaller teeth size, first hominin to leave Africa -- BUT, too early?) -fossil evidence stretches 1.5 million years - it is by far the most geographically widespread species apart from H. sapiens -first known human species to make hand axes (Achulean tools) -meat was a key part of their diet (early Erectus were probably scavengers, they likely evolved hunting capabilities later) -may be the earliest humans to have controlled fire -first Erectus fossils were found in 1891 in Java by Eugene DuBois (the "Java man"), dated to 1-0.7 mya -thigh bone indicated erect, human-like posture, but the skullcap indicated that its brain was much smaller than humans today + had a large brow ridge -important erectus fossils: Turkana boy, Peking man and Dmanesi skulls -cranial features: long, low skulls with robust features; prognathic lower jaw; projecting nose; widest point of the cranium is near the base of the skull; large supraorbital torus (related to mastication); post-orbital constriction (narrowing behind the eyes); nuchal taurus (bony projection at the rear of the skull where the neck muscles attach); sagittal keel -dentition: decreased molar size from Australopithecines; parabolic dental arcade over rectangular shape; larger front teeth (incisors) compared to Australopiths; -brain sizes from 750-1200 cc (larger than earlier Homo species), average = 1000 cc; the upper range is near the current lower for H. sapiens; possess a very similar asymmetry to modern humans (likely possessed the capacity for thought/language -postcranial features: very similar to modern humans; relatively longer legs/shorter arms than earlier species; obligate bipeds; loss of earlier tree-climbing adaptations seen in Australopiths -average height - 4'9''-6'1'' -average weight: 88-150 lbs -sexual dimorphism decreased - but still shown

3 big events that made South Africa the center of research on Hominin origins

1) Raymond Dart discovers the Taung Child in South Africa in 1924 2) Louis + Mary Leakey discover Zinjanthropus (Paranthropus boisei) in 1959 3) Donald Johnston discovers "Lucy," Australopithecus afarensis, in the Hadar region of Ethiopia in 1973

H. erectus sites in China

DRAGON BONE SLOPE -initially dated to 1.96-1.78 mya - very controversial date, would be the earliest erectus date -new dating: 1.8-1.4 -far flung sites show that H. erectus emerged in Africa and left before the Achulean tradition was created -bones used as medicines + aphrodisiacs in Chinese culture ZHOUKONDICUR CAVE (near Beijing) -best known H. erectus site in China -at least 40 individuals uncovered in the 1920s - lost during the war -casts were made, but we can't do tests on casts -evidence of scavenging - cut marks over bite marks

first human-like traits to emerge in the hominin fossil record

bipedal-walking and smaller, blunt canines

closest relatives/LCA

humans' closest relatives are chimps and bonobos (among the great apes), they shared a LCA about 6 mya

why is the term 'missing link' inappropriate?

it implies that there is one ancestor that uniquely forms the link/bridge between our common ancestor with the African apes and ourselves

Piltdown Man Hoax

in 1912, Charles Dawson discovers unusual human-like skull fragments. he names it Eoanthropus dawsoni - it was hailed as the 'missing link' in human evolution (this fossil turned out to be totally fake). the Piltdown Man Hoax was the idea that there was a missing link that would partly resemble a human and partly resemble an ape. there is NO missing link - that isn't how evolution works -this discovery was accepted because it fit preconceptions: near-modern intelligence + originated in Europe. it had a modern-looking cranium and an ape-like jaw, so it could be the missing link between apes/humans -in 1949, the fluorine test was applied to the Piltdown Man (fluorine test - measures the amount of fluorine that has leached from the surrounding soil into the bone). it was discovered that the skull was of a totally different age than surrounding fossils -eventually, Piltdown was found to be a fraud-skull - the skull of a modern human and the jaw of an orangutan

Australopithecus afarensis

-3.8-3.0 mya -Ethiopia (Hadar) in 1974 by Donald Johanson -most well-known species, Lucy = most famous specimen (40% complete), dated to 3.2 mya -much of what we know about this genus comes from studying Lucy -Johanson posited that she was a female based on her small size, developmentally she was an adult (probably 12-18 years at death) -many similarities to Miocene apes suggesting relatively recent divergence from these period apes -but differences suggest that afarensis may be an important ancestor of modern humans -has front teeth that are smaller than apes but larger than modern humans -molars are very large -canine teeth are smaller (no canine diastema) (not using their physical bodies for threats) -gorillas have large canines that "lock" when their mouths are closed - their jaw can't move side to side -modern humans do 'rotary chewing:' smaller front teeth facilitate the side to side motion of the jaw (helps protect dentition) -displays prognathism, but reduced -ape features: massive jaws, flaring cheekbones w/big zygomatic arches, some fossils have a sagittal crest (protrusion of bone at the top of the head, allows for the attachment of chewing muscles) -dentition analysis shows that hard/brittle foods were part of the afarensis diet -average brain size like apes, about 440 cc -post-cranial skeleton is decidedly human, clearly bipedal (hips, pelvis, legs + feet), BUT arms are longer than humans', curried fingers and a muscular upper body -much narrower birth canal than humans, their babies must have had much smaller heads at birth than humans -POTENTIAL tool use among this species

Australopithecus anamensis

-4.2-3.8 mya (oldest) -found in Kenya -fossilized remains uncovered at sites in Kenya around Lake Turkana -environment would have been forests/woodlands that grew up around the lake -ape traits: parallel molars, diastema + large canines, longer forearms -human traits: canine teeth vertical, not angled like typical ape canines; heavy tooth enamel; bipedal body structure -suggests that they are capable of bipedality, but are still active in the trees -strong jaws + heavily enameled teeth suggest that this species ate hard, abrasive foods -leg bones and big toes suggest strong bipedalism -forearm length/flexible wrists suggest that this species was an adept climber as well -appears to be a direct (or very close) ancestor of a second species of A. afarensis

Eugene Dubois

-Dutch doctor interested in human evolution and the search for fossil human ancestors -he was stationed in Indonesia in the army -first began his fossil search in Sumatra, but had no luck -he then moved to Java, where he was very lucky -1891: found 2 fossils close to each other (a large skullcap and a femur that showed upright posture) -skull cap showed largish brain: about 1000 cc (but too small to be human, which averages about 1300 cc) -he named it Pithecanthropus Erectus (upright ape-man) -would be renamed Homo Erectus -DuBois believed there was a missing species between humans/apes -instead of revolutionizing the study of human ancestors, his 1894 publication was largely ignored (b/c it didn't fit the preconception of where the ancestor would be found/what it should look like) -DuBois was embittered and locked his discoveries away until the 1920s -the two principle problems with the fact that scientists were not accepting of DuBois' finds: 1) scientists believed that a large brain size was the defining characteristic of our ancestors, and upright posture was less important (the 'missing link' was believed to have a chimp body and a human head) 2) ethnocentric ideas: Europeans believed themselves to be the most advanced, therefore origins must have happened in Europe

(human) bipedal adaptations

-FORAMEN MAGNUM: big hole in the bottom of the skull where the spinal cord and brainstem connect. it is located underneath the skull for bipeds, behind it for quadrupeds (this determines spinal orientation) -SPINE CURVES: humans + great apes both have curved spines, but they curve in different ways. human spines are a stretched-out S-shape, other great apes have a C-curve because there is only one curve in the spine. there is more stability/shock absorption granted by the S-shape -PELVIS: located directly under the trunk, so it supports a lot more weight. humans have larger and thicker pelves to support more weight. larger birth canals to accommodate big-brained babies. hip joint is reoriented forward and strengthened for wear + tear of bipedal locomotion (pelvis is more durable, thicker bone deposits @ ephemeral attachments). more muscles around the hops (we build up substantial gluteal muscles because of increased muscle attachment space) -LOWER LIMBS: longer and more muscular legs than other apes, these facilitate bipedality. knees are oriented towards the center of our bodies, and feet stay the same distance apart -FEET: big toe is aligned with other toes (non-diverging - non-opposable toe). feet are expanded (increased muscle attachment on the ball of the foot, heel and big toe). human feet are rigid, other primates have very flexible/dextrous feet. people who don't have use of their hands can be quite dextrous with their feet, but it takes a lot of practice (it isn't innate, it is learned)

Denisovans

-a newly discovered group of Homo found in 2010 in Denisova cave -dates to about 52-195kya -doesn't have a specific name because it lacks a type specimen (a fossil that is complete enough for future finds to be compared to) -humans also interbred with Denisovans across several time periods/spaces -mitochondrial DNA suggests that our LCA was 1 mya

advantages to bipedalism

-allows hominins to CARRY THINGS while walking, such as children, food, rocks + sticks to throw, running away while eating (useful for scavenging) -makes them TALLER - able to see over the tall grass in the savanna (BUT, research has suggested that hominins developed bipedality in the forests, not the savanna, and other animals just climb, stand on two feet temporarily, or fly...) -gives hominins a LONGER REACH - makes it easier to get food in high trees/bushes. BUT, there are other ways to access these fruiting trees -ENDURANCE: definite advantage of bipedalism, hominins can walk/run for a very long time without becoming exhausted. we aren't as fast as quadrupeds, but we can go much further. bipeds use much less energy (it takes less energy to cover two limbs than four). good adaptation for long walks in search of food in patchy forests. the earliest hominins may not have been fully upright (therefore they may have had less endurance). ALSO, there are other animals with extreme endurance, like camels -HEAT DISSIPATION: a vertical posture cools the body by presenting a smaller surface area to the sun, giving more of the body access to cooling breezes, and getting the face and head away from the hot ground. humans also lost their body hair and developed a lot of sweat glands, this suggests that thermoregulation was an important aspect of human evolution

isotopic analysis for diets

-analysing carbon and nitrogen in the bones of humans and animals can determine the proportion of food in their diets -carnivores tend to have more nitrogen (this is Neanderthals) -omnivores tend to have more carbon

trends in human evolution

-as humans diverged from other primates, they underwent a series of anatomical changes, including bigger brains, bipedal locomotion, thicker tooth enamel, reduced pre-molar honing, and reduced sexual dimorphism

why are teeth useful in the fossil record?

-b/c of their highly mineralized natures, teeth are the best preserved fossil elements in fossil assemblages -tooth histology is the most effective means of determining eruption ages and age at death in juvenile hominins

Homo neanderthalensis

-best known evidence dates from 130-30 kya -classic Neanderthals ("type species") date from 70-35kya -found in Europe + SW Asia -first found in the Neander Valley, Germany in 1856 -thought to be the "missing link" to apes, researchers emphasized the primitive characteristics -more pronounced dip between the brow ridges than H. erectus -skull is higher + more rounded (no sagittal keel) -faces + jaws not as massive -bigger skulls and long, long craniums -cranial capacity: 1300-1640cc -large mid-facial projection and huge nose (hypothesis is that it warms up air) -large front teeth, bony faces and large brow ridges -some have occipital buns -made Mousterian tools -shorter and stockier bodies (adaptation to the cold)

Australopiths

-best known genus (widely distributed, and most diverse of the early African hominins) -4.2-1.2 mya -the longest enduring hominin yet known -general features: bipedal, brain slightly larger than chimps, reduction in size of front teeth, increase in size of molars + enamel thickness -some of the species could be ancestral to genus Homo, but relationships to one another are not entirely clear -Raymond Dart discovered the Taung Child in 1924 and coined the term Australopithecus (southern Ape) -Australopiths are mainly found in East/South Africa -some specimens found in Chad, but we don't really understand the relationship yet

Homo neanderthalensis + H. sapiens LCA

-both fossil and genetic evidence indicate that the LCA was likely 50-200 kya -common ancestor is likely H. heidelbergensis

Levallois tools

-created about 200 cya, increasing use of prepared core technologies to make flake tools -increases standardization + efficiency -core was pre-shaped so similar sized and shaped flakes could be removed -hafted onto wooden/bone shafts, game changer in hunting -advantages: faster creation process, sharper tools, more standardized tools possible, conservation of raw materials, more cutting edge per square inch of raw material, could make tools away from the source -sites: lakeside hunting site, schoningen site, DE

pre-modern human dating issues

-date ranges 800-125 kya -too young for K/Ar dating, too old for C-14 -requires different sets of dating techniques: uranium series, ESR -problematic techniques w/ pretty large error factors possible

phylogeny

-depicts evolutionary relationships as a branching tree. not every fossil was directly ancestral to us -also, ancestor and descendant species could overlap in time. -evolutionary dead-ends have no modern ancestors

how to gather evidence of fire?

-direct evidence of fire is much harder to find than tool use (because fire is ephemeral) -so instead, we use indirect evidence (things that could have been burned by the fire, like bones; also, change in soil composition/color (ecofact); microstrategraphic analysis of ash)

Laetoli footprints

-discovered in Tanzania by Mary Leakey in volcanic ash -ash dated to 3.6 mya (dated with A/Kr) -determined to be made by A. afarensis -likely made by two individuals: 1 larger and 1 smaller -shows a bipedal "heel strike" gait: toes push off, heel put down first -close spacing of the footprints shows that the people who left them had a short, slow stride (suggests that the species had shorter legs) -only much later did hominins evolve longer legs to enable them to walk further -researchers suggest a male/female walking together -sexually dimorphic: 1 male + 1 female -males weigh 1.5x as much, about a foot taller

features of earliest hominins

-earliest hominins lack the derived features found in later hominins, and their inclusion in the hominin lineage is largely based on the reduction in canine size, absence of the C/P3 honing complex, and the presence of morphological adaptations for habitual/obligate bipedality generally found in the post-cranial skeleton, particularly the pelvis/hindlimbs -bipedality is generally considered to be the hallmark of hominins

Ardi

-female, about 4 ft tall and 100 pounds -60% of skeleton found -environment Ardi was found in: currently arid. plant and animal fossils associated with Ardi indicate that the environment was wooded -teeth: tooth enamel suggests a diverse diet of fruits, nuts, leaves, etc. (thicker enamel gives protection). blunt canines are a like modern humans', not the fangs of modern chimps. little sexual dimorphism in the teeth (suggests less violent male competition for mates and possible a high degree of cooperation among males and females) -facial profile: Ardi had a projecting lower face but much less so than other chimps. other aspects of the skull are quite different from chimps -pelvis/lower limbs: analysis of pelvis/lower limbs suggests she would have been a tentative upright walker, would have been a poor runner. very able climber and likely spent a lot of time in the trees. did walk bipedally, just not as comfortably as later humans -hands + upper limbs: Ardi had relatively short palms and fingers, so not adapted for knuckle-walking. she did not have the specialized anatomy to allow her to swing/hang the way apes do. her hands were more similar to those of earlier apes rather than modern ones -feet + lower limbs: strong glute muscles would have enabled her to stand upright fairly efficiently. feet have rigid toes - not the flexible feet of modern apes. the big toe diverges as does modern apes

advantages of fire to our evolution

-fire has been imperative to our development (allowed us to cook food, making it easier to digest; also breaks down toxins in plants and kills pathogens; and cooked foods are way more energy efficient, you get way more calories from what you eat) -evidence of regular cooking doesn't appear until 350kya-400kya in the Levant (Qesem (cave) provides evidence of a permanent hearth -keeps you warm (helped our ancestors expand their geographical range) -grants access to light and protection from predators

Orrorin tugenensis

-first SOLID evidence of bipedalism (unsure about Sahelanthropus tchadensis) -mandibular fragments, isolated teeth, and a few post-cranial elements were found in Tugen Hills in NW Kenya, dated to 6.2-5.6 mya (we are more confident in these dates because the fossils were dated with radiometric dating) -found in October 2000 - press called the find the "Millennium Man" -name means "original man" in the local language of Kenya, where it was found -dentition is very ape-like, so arguments for its inclusion in the hominin lineage coalesce around its likely habitual bipedality -lower limb bones indicate a strong bipedal locomotion (angled femurs) -individuals of this species were approximately the size of modern chimps, and had small teeth with thick enamel, similar to modern humans -very controversial as to where this species sits on the evolutionary tree, but recent study has determined that it may be more similar to Pliocene hominins (distinct from modern great apes/Homo)

Homo heidelbergensis

-first named for a specimen near Heidelberg, Germany -date: 700-400 kya -larger brain than H. erectus -higher forehead, smaller face, thinner bones, less prognathic than H. erectus, less extreme supraorbital torus, less post-orbital constriction -tall + muscular -extensive wear on teeth (using as tools?) AFRICAN SPECIMENS: -several skulls, lots of variation -600kya-125 kya -1100-1400 cc (Cranial capacity) -best site = Bodo, Ethiopia (dated to 600kya) -transitional features: large brains, has cut marks on the vault that indicate it was intentionally defleshed (cannibalism) EUROPEAN SPECIMENS: -several specimens, dating 600-160kya in France, Germany & Greece -1200-1325 cc -England - Boxgrove site (hundreds of flint handaxes - we think they hunted there) ATAPUERCA, SPAIN (Sima de los Huesos) a least 6000 hominin bones that date back to 400kya (Could be evidence of possible intentional burial system)? -made Levallois tools -first species that we have evidence of shelter for

Sahelanthropus tchadensis

-found in Chad in 2001 (well outside East Africa, where most hominin fossils are found), may be the oldest fossil hominin recovered so far (potential earliest hominin?) -suggests that human ancestors were widely distributed across the continent -age was determined biochronologically - lack of volcanic tuffs precludes the use of radiometric dating -probably 7.2-6.8 million years ago (evolving right at the end of the Miocene) -dated using biostratigraphy from Kenya (VERY tentative) -fossils recovered include a complete, but crushed, cranium, and isolated mandibular fragments + dentition -all we know is from skulls - not much in terms of post-cranial remains -position of foramen magnum suggests an upright posture/habitual bipedality (strongly suggests early development of bipedalism) -all of the discoveries/assumptions about this species are contentious - some people believe that the fossils belong to a female ape, not a male hominin -blend of ape/hominin characteristics -ape-like characteristics: brain size = 320-380 cc, huge surpraorbital torus (brow ridge), large muscle attachments on skull, elongated skull -hominin-like characteristics: small, vertical face (less prognathic), small canines with reduced honing -intermediate features: position of the foramen magnum (sort of in between apes & humans), suggests some degree of bipedality (no post-cranial finds, so foramen magnum is the only clue as to bipedality)

Australopithecus sediba

-found in South Africa in 2005 by a 9-year-old in Malapa reserve -dates to about 2 mya -brain 420-460 cc -chimp sized, long arms -much more human-like brain, face, teeth, pelvis and legs -gracile Australopithecine -possible ancestor to modern humans -not entirely sure how sediba fits into the evolutionary tree

fossil preservation in South Africa

-good preservation of fossils linked to limestone deposits -limestone forms from the skeletal fragments of marine organisms -limestone is full of cracks/fissures and is easily dissolved by rainwater -consequently, limestone deposits are often filled with caves/tunnels

H. erectus discoveries in Java

-home of the first erectus find -6 total sites have been found since in east java -erectus arrived by 1.8-1.6 mya -we think that they came via a land bridge (probably couldn't make boats) -no stone tools associated with the java sites -but how were they butchering meat? -during his excavation, DuBois collected a lot of skulls/other non-erectus fossils -we know they were eating shells for food, but also potentially using them as tools? -limited evidence of art on shells

advantages of stone tools

-hominin teeth + nails aren't strong enough to tear through tough animal skin, break open bones, etc -tools likely expanded their variety of food -weapons help chase away predators

bipedal locomotion

-hominins developed this before large brains (we used to think big brains came before bipedality) -hominins are bipedal hominoids -hominins are all forms of primates that habitually walk on two legs

trends in human evolution: reduced sexual dimorphism

-human ancestors appear to have been very sexually dimorphic until relatively late in human evolution -sexual dimorphism can't be used to distinguish human ancestors from other primate ancestors in the fossil record -some species of apes have about the same degree of dimorphism as humans do, like chimps + bonobos

trends in human evolution: big brains

-humans have extremely large brains compared to other species of primates -average size = 1300 cc -human brains didn't start to enlarge significantly until about 2 mya, which is very late in evolution

Homo naledi

-hundreds of H. naledi bones discovered in a South African cave in 2013 - largest find ever made on the continent -1500+ bones from at least 15 individuals, ranging from infants to elderly adults -puzzling combo of primitive + derived characteristics -anatomy suggests that it walked efficiently on two legs, but it had ape-like shoulders and fingers that could have helped it climb/hang from trees -remains dated between 236kya-335kya -researchers favor the idea that other members of the species disposed of bodies in the cave intentionally/repeatedly (some scientists think this behavior is too complex for a big-brained species) -wrists and hands are well-suited to tool-making, but no tools have been found with fossils

Paranthropus boisei

-hyperrobust (most prominent features of Paranthropus, even thought it didn't get the name robustus) -2.6-1 mya -brain: 515 cc -East Africa -very wide + dish-shaped face to allow for massive jaw muscles along the cheeks -molars were 4x the size of modern humans' -noticeably sexually dimorphic -the first P. boisei was found by the Leakey's in East Africa at Olduwai gorge -they found this species in the 1950s after years of work -their son Richard and his wife Maeve continued their work -this species is thought to have lived in environments that were dominated by grasslands but that also included more closed, wet habitats associated with rivers + lakes

endocast

-inside surfaces of the skull are negative impressions of the surface of the brain -sometimes they occur naturally, like the Taung Child -or they can be made with latex poured into an empty skull

lumper vs. splitter debate

-is Homo habilis really a member of our genus? it has the same brain as Australopithecines -is Homo rudolfensis its own species, or a large specimen of Homo Habilis? -some physical variations found in different geographic areas/time periods has encouraged some anthropologists to divide Homo Erectus into several species/subspecies (such as Homo ergaster, which was limited to Africa and has a higher cranial vault, smaller face and a more gracile build, and Homo antecessor (limited to Europe, modern looking face with slightly smaller brain, and asian fossils, which keep the archetypical Erectus?) or is this all one species? -lump Paranthropus into the genus Australopithecines, they are just the more robust version of this species. splitters want to split Paranthropus into a separate species from Australopithecines -in 2013, analysis of 5 erectus skulls from Dmanisi says that there are a lot of similarities to H. Habilis - lumpers say this could be one species -some scientists lump all mid-Pleistocene hominins (heidelbergensis, antecessor and rhodesiensis into one species - heidelbergensis). splitters argue that there is far too much variation between the Eurasian/African fossils to be one species -is H. neanderthalensis a subspecies of Homo, or is it its own species? we clearly could interbreed with them, so by the standard definition of species we have to be the same

paleoenvironment of the earliest hominins

-it has been posited that the origins of bipedality in our lineage had its roots in the expanding savannas of the Pliocene -however, the ecological contexts of the earliest hominins suggest that bipedalism/the expansion of the savanna may be a tenuous link -the beginning of our lineage likely occurred in more closed/wet habitats as opposed to the open savanna

idea of primitive Neanderthal

-key site: La Chappelle aux Saints, France -found in 1908, examined by Marcellin Boule in 1911 -he reconstructed Neanderthal man as being bent over and having big toes, put the fossil at 20kya -in 1957, this was reexamined - they found that the individual had developed severe osteoporosis which was making him bent over (he was an older man) -divergent toes had just been a conjecture, there was no evidence (very little in the way of post-cranial remains) -the damage had already been done - the idea of the primitive Neanderthal man was already widely accepted -these days, there is a tendency to over exaggerate the modernness of Neanderthals

island rule

-large-bodied species shrink when they get to an island and smaller species get larger -this is because of an absence of natural predators on islands, a scarce resource supply may favor smaller body sizes, and smaller individuals could probably produce more offspring

first fires started associated with hominins

-likely started by natural fires (lightning, forest fires) -flames were probably transferred from natural sources and kept alive -maybe started between 2-1.6 mya -starting fires w/o naturally occurring flames likely happened about 400kya

fossils + limestone

-limestone is frequently filled with marine fossils -it can also contain more recent fossils of organisms that fell into fissures/caves and became preserved as casts or molds, or mineralized with the limestone -South Africa - lots of limestone caves = preservation, limestone mining has exposed a lot of preserved fossils -BUT, limestone sediments cannot be dated with K/Ar, often can only be dated by using sediments containing fossils of known ages (that have been dated elsewhere) -biostratigraphy (relative dating)

Rift Valley of East Africa

-major valley formed by a fault line (place where two continental plates meet) -process of pulling apart creates valleys, exposes strata that is good for fossil recovery -the Rift Valley runs from the Afar Depression in Ethiopia through Kenya, Tanzania and Malawi

disadvantages to bipedalism

-more easily seen by predators: tallness is suggested as an advantage but it also makes us more visible to predators (BUT, lots of other animals have the same problem) -exposes soft underbelly: more susceptible to frontal assaults (where all of our internal organs are stored). most injuries to the gut (without medical attention) are fatal -we run slower: bipeds have good endurance but cannot compete with most other animals in sudden bursts of speed -reduced agility: we cannot change direction quickly, we have to run slower or make wide turns. many other animals can switch directions without significantly slowing down -lower back problems: upright posture puts a lot of pressure on the lower back. the lower back takes the entire weight of the head + torso. this problem gets more severe as you age -hernias: a hernia is the protrusion of an organ or piece of intestine through a weakness in the abdominal wall. gravity causes the guts of bipeds to slump downwards, putting pressure on the lower abdominal wall (quadrupeds' organs are more evenly distributed) -leg injuries = incapacitating: today, we have excellent protheses, so people who have lost limbs aren't disabled. in the past, leg injuries were disastrous because you couldn't walk. many quadrupeds do just fine on three limbs (they can still move), but bipeds need help when they have leg injuries -instability: humans fall, trip and slip a lot. falling leads to heavy impact, you could fracture other things

Turkish family that walks quadrupedally

-most humans were quadrupedal at one point in their lives (crawling) -there is a Turkish family that habitually walks quadrupedally, sensational journalism has suggested that this family was evidence of pre-bipedal humans -actually, they just have an anomaly in their brains that affects coordination/balance, they are incapable of regular bipedal movement

trends in human evolution: reduced premolar honing

-most living apes have sectorial premolars that sharpen their canines when they close their jaws -they also have a diastema between their teeth to accommodate for their large canine teeth -humans don't have these (reduction), but so do some fossil apes, so this can't be a good identifying feature

Homo habilis

-name means "handy man" -first fossils found by Louis + Mary Leakey's team in 1960 -upright posture, bipedal + manual dexterity - the original three requirements to be a member of the genus Homo (but walking upright is something the Australopiths did too, so the definition changed) -

Homo floresiensis

-nicknamed "the Hobbit" - evidence of island dwarfism? -lived until at least 17 kya -discovered first specimens (from a 30 year old female - LB1) in 2003 on the remote Indonesian island of Flores -about 3.5 ft tall -some dating has suggested that this species lived from 95-12 kya -unclear how this species fits into the hominin family tree -based on LB1, scientists estimate that this species weighed between 35-79 lbs, had a unique combo of ancestral + derived features -skulls resemble early Homo -teeth + jaw resemble Australopiths -study of this species' wrist bones proved that it was a separate species from modern humans -uncovered Oldowan tools in the same cave -evidence of butchering/harnessing fire in the Liang Bua cave -very small brain - 400-425 cc - originally accused of being an abnormally small H. sapiens with a variety of growth/hormonal conditions -most likely ancestor is erectus

Hunters or Scavengers?

-non meat-bearing bones were smashed open for marrow - likely scavenged from kills made by other animals -cut marks are found on the shafts of bones - already separated from other carcasses -cut marks on the core sometimes overlie carnivore tooth marks, if the hominins got there first, it would be the other way around

Ardipithecus kadabba

-older of the two Ardipithecus species -mandibular fragments, isolated teeth, and hand and feet bones were found in Ethiopia (5.8-5.2 mya) -more solid date b/c of radiometric dating -probably smaller in body/brain, similar to modern chimps -BUT, like later hominins, they have smaller canines with thick tooth enamel -the toe bone suggests bipedality - larger toe bones give a good surface to push off of when moving bidepally -originally thought to be a subspecies of Ardipithecus radius, but determined to be its own species because of its ancestral C/P3 honing complex -determined to be a habitual biped

Gran Dolina site

-oldest H. erectus site in Europe (in Spain) -remains of several individuals, occupied between 1.1mya-800kya (fairly secure dates) -recovered during railroad construction -fossils found are clearly on the transition to modern humans -tools are improved Oldowan + chopping flakes only (they must have left before the development of Achulean tools) -in Europe, there have been more tools found human remains -toothless skull - evidence of compassion -CANNIBALISM: evidence of erectus cannibalism; evidence of human/animal bones treated the same way

Homo rudolfensis

-originally classified as a large specimen of Homo habilis -large brain: about 775 cc

meat eating in hominins

-over hominin evolution, brains have increased by 300% -meat-eating was one of the most pivotal changes in our ancestor's diets that led it to many of the physical, behavioral and ecological changes that make us uniquely human -our earliest ancestors probably had diets similar to modern chimps - fruit, plant parts, nuts + insects -micronutrients from meat are so important that even small scraps of meat may be worth the energy expenditure that cooperative hunting entails -advantages to eating meat: high quality protein, marrow + fat = high calorie and nutrient rich, easy to digest -impacts of a meat-based diet: may have reduced the need for huge dentition, may have reduced the amount of time early hominins spent finding and eating food

early Homo

-post cranial skeleton similar to Australopiths -brain was about 20% bigger, 600-700 cc -reduced jaw -smaller teeth but relatively parallel molars -several varieties of early Homo - relationships not well understood -2 major early Homo species: Habilis (2.4-1.5 mya, East Africa, Kenya, Tanzania, used stone tools) + rudolfensis (2.4-1.6 mya, Kenya) -Habilis: exhibited a marked brow ridge; a short, prognathic face; a brain size of about 600-700 cc; smaller molars -Rudolfensis: exhibited less of a brow ridge; a longer, flatter face; brain size of about 775 cc; and larger molars -stone tools were a fundamental change for this species -larger brain = larger capacity for culture -stone tools = material evidence for problem solving

Genus Paranthropus

-robust Australopithecines -bodies like other Australopiths -brains are slightly larger, but within normal range -massively robust skulls with lots of bone -skulls: sagittal crest; wide, flaring zygomatic arches; huge jaws + molars

Pre-Australopiths

-seems that Ardipithicus radius may have been an early ancestor of Australopithecus based on physical natures + behavioral clues that suggest a direct lineage -earliest known direct ancestor on our lineage

fossil preservation in East Africa

-soft volcanic sediments = preservation -active volcanoes - can use K/Ar or Ar/Ar dating -Rift Valley splitting apart - exposing more fossils -everytime a volcano erupts, it leaves a unique volcanic ash based on what was inside the volcano

when do hominins/Homo appear?

-some very early forms of POSSIBLE humans appear at the end of the very end of the Miocene (probably more similar to modern Great Apes) -earliest true hominins appear in the Pliocene -the early members of genus Homo appear in the Pleistocene

most updated model for evolution: the Braided Stream model

-takes into account our inbreeding with other hominin species -depicts evolution as a series of channels that sometimes branch off etc other, but also sometimes reunite at some points -shows how species can reunite after a split from a common ancestor -highlights the importance of gene flow in our evolution for a species -discovery of human hybrids: Romanian jaw that showed human/Neanderthal characteristics

how does Paranthropus relate to us?

-the three species of this genus likely do not relate to the human lineage, separate branch of hominin tree -may have lived alongside later Australopithecines and early Homo species in Africa before going extinct

why are the Neanderthals the best known species?

-they are ancient Europeans (most paleoanthropologist are of European descent and people like to study their own people) -they are found largely in Europe (many Neanderthal remains are found in Southern France and this is a great region to conduct work in) -for these reasons, we know a lot more about Neanderthals because this is the route many researchers choose to follow

what happened to Paranthropus?

-they were highly specialized in their particular environment -very successful but was also their undoing when the environment changed -not a failure - survived 1.5 million years -modern Homo sapiens have only been around about 300 kya

Achulean tools

-tools made by Homo erectus around 1.6-7 mya -sophisticated tools crafted on both sides to be thinner and sharper (bifacial flaking) -soft hammer percussion: a secondary step where bone, antler or softer materials were used to finish the tool -probably used to butcher meat, among other purposes -prior to that, early H. Erectus used more primitive tools (like the ones found at Dmanisi), like rock flakes knapped to a sharp edge -advantages over Olduwan tools: straighter edges, thinner and sharper; specialized with a wide variety of functions, standardized tool shape (found over many sites) -required effective communication to pass along the ideas of form and design -significant forethought + planning required: had to find the right tools and conceptualize the finished tool before creating it

thirst for blood/killer ape theory

-when Raymond Dart found the Taung Child in 1924, there were small bones around the fossil that made it seem like Australopithecines were meat-eating predators -violent trauma to the head showed that hominins were actually prey -Raymond Dart believed in the thirst for blood as a driver for evolution -Killer Ape Theory - our hominin evolution was marred by violence even among hominins -Washburn (American anthropologist) believed/published that hominins spent most of their history being prey -Taung Child was likely killed by an ancient bird of prey -evolutionary history from the time we were prey is reflected in us today

apes + knuckle walking

it appears that apes developed their specialized forms of locomotion (knuckle-walking, and very flexible feet for climbing) AFTER they split from the human line. we are used to thinking of ape traits as being primitive, but they appear to be as modern as the human traits that make us different from them

Ardipithecus ramidus

-younger of the two Ardipithecus species -also found in the same region of Ethiopia as Ardipithecus kadabba, about 5.6-4.4 mya -many A. ramidus remains were uncovered from Aramis site in Ethiopia -skull fragments show foramen magnum located under the skull - degree of bipedality -partial skeleton (60% complete) named Ardi is of this species - large sample size for an early hominin (lots of fossils) -remains dated to 4.4 mya -uncovered in Aramis site -female, about 4 ft tall, about 100 lbs -Ardi shows a number of characteristics linking her to later hominins, but also has many primitive characteristics -'mosaic' of derived/primitive features suggests that it was a facultative biped, able to climb in trees effectively by palmigrade quadrupedalism

4 lifestyle adaptations that might grant a hominin entry into the genus Homo

1) an adult brain size greater than 600 cc 2) limb proportions similar to Homo sapiens (longer legs compared to arms) 3) the use of language (can be difficult to infer from the fossil record) 4) manufacture/use of stone tools

meat eating in humans vs. chimps: 4 differences

1) early humans were already consuming much larger animals, chimps only hunt smaller animals than themselves 2) early humans generally used tools to process/procure meat 3) its likely that early humans scavenged for meat, chimps don't scavenge 4) our ancestors didn't always eat food as soon as they encountered it - this delay in consumption isn't observed in chimps

two forms of hominin bipedalism

1) habitual bipeds: walking on two legs is most efficient, but they have other options 2) obligate bipeds: committed to bipedalism and cannot locomotive efficiently any other way -modern humans are obligate bipeds. the human body is designed to walk on two legs

WHY did hominins become bipedal (theories)?

1) so that hominins could carry things in two hands while walking (such as carrying children & food, sticks & rocks to throw, running away while eating) 2) SAVANNA HYPOTHESIS: efficiency of upright walking - hominins evolved this adaptation in response to climate change (as forests shrank, hominins decided to move from the trees to get to the next patch of forest and the most efficient way to do that was to move bipedally (moving on two feet is more efficient in the open) 3)

adaptive introgression

material from one species moves into the gene pool of another species, and then is selected for, so it sticks around (sometimes, these genes can become harmful)

the genus Homo

the earliest fossils of our own genus date to 2.3 mya (Homo is believed to have begun 3.0-2.5 mya). the earliest fossils are found in East Africa

orthogenesis

the oldest (discredited) model for thinking about change over time, presents a linear model of evolution in which species progress from one form to the next towards some kind of goal/ideal (the "March of Progress"). this concept made it easy to think that the Piltdown Man was a missing link, because it was halfway between an ape/human

pre-modern humans

three species included in this - heidelbergensis (primarily European, also some African + Asian), neanderthalensis (found only in Europe+ SW Asia), denisova (more closely related to Neanderthals, found in Siberia + SE Asia)

genus Ardipithecus

two species recognized: Ardipithecus kadabba (5.8-5.2 mya) and Ardipithecus ramidus (5.6-4.4 mya)