Biological Anthropology Final

Bones and teeth absorb all of the following from the soil in which they are buried

Radioactivity, electrons, fluorine

earliest possible hominid

Sahelanthropus tchadensis, Orrorin tugenesis, Artdipithecus (Ar. ramidus & Ar. kadabba)

Paleobotany & Palynology

can recreate plant life of the time by studying plant fossils (paelobotany) and pollen fossils (palynology); indicates which food species or habitats might've been available

perimortem

changes happen at or around time of death

postmortem

changes occurred after death

The cranial cresting of the robust australopithecines was due to

chewing and neck muscle attachment

The cranial capacity of the australopithecines was similar to that of modern

chimpanzees

Many paleoanthropologists consider themselves to be "lumpers" when it comes to fossil specimens, and only recognize a small number of fossil hominid species. This means that they must accept a high degree of intraspecific variation. What is one explanation for the intraspecific variation that we see in the fossil record?

sexual dimorphism

Neandertal Cranial Morphology

-1200-1740 cc w avg. of 1478 cc -occipital bun -long cranial vault (lack high forehead; max bredth in the middle) -large, shoveled incisors -large nose large face -arched brow -inflated cheeks -midfacial prognathism -retromolar space -receding mandibular symphysis (lack of chin) -extreme wear on teeth (incisors worn down bc used as tools)

Relative Dating Techniques

-tells you age of one thing compared to another (w/out actual date) 1. Superposition - relies on stratigraphy (deeper is older); tells relative ages within one area, but doesn't tell ages relative to another area unless you have continuous geologic layers (lithostratigraphy) 2. Biostratigraphy (aka faunal relation) - when animal fossils at a site can be compared (index fossils); helps determine relative ages between sites 3. Chemical Tests - can determine whether set of fossils is from the same time period (ex: fluorine dating); compare bones and teeth from same site to see if from same time period

Homo erectus Hypotheses

1. H. erectus was a single world-wide species -all fossils resembling H. erectus (1.8 mya - 300 kya) across world are lumped into one species that evolved in Africa, colonized the OW, and was ancestral to H. sapiens 2. was several species -fossils divided into species in different geographic regions; 3 main species discussed are H. ergaster in Africa, H. erectus in Asia, H. antecessor in Europe -in scenario, only H. ergaster are ancestral to living humans and 2 other species went extinct 3. all fossils beyond early Homo (H. habilis, H. rudolfensis, H. garhi) are Homo sapien -H. erectus should be abolished and all its fossils should be classified as Homo sapien, as a diverse polytypic species that spreads around the globe and slowly develops into modern humans around the entire world

3 stages of forensic investigation

1. recover remains (using archaeological techniques) 2. Laboratory analysis 3. report findings (and/or testify)

Evidence Ardi found in Woodland

1. stable carbon isotopes indicate C3 plants (trees & shrubs) 2. fossilized plants and pollen include hackberry trees, figs, palms 3. browsing ungulates (those that eat twigs and leaves) were found rather than grazing (those that eat grass) 4. Monkeys in area were colobines, which are exclusively arboreal in Africa

Most modern human genes have a coalescence time within the last 200 thousand years, and the most genetic variation of modern humans is found in people of African descent. These facts best support which hypothesis for modern human origins?

African Replacement

Candidates for Homo genus ancestor

Au. afarensis & Au. africanus (gracile Australopithecines), Au. garhi

When primates started to evolve

Cenzoic Era - climate was cool and dry due to asteroid hitting Earth and sending up dust and ash to block sun's rays so herbivores starved b/c many plants died, and carnivorous dinos died b/c didn't have prey ---> niches opened for small insectivorous mammals like our primate ancestors

Neandertal Sites

Engis in Belgium Feldhofer La Chapelle-aux-Saints La Ferrassie

A half-life is the amount of time that must pass before all the electron traps have been filled with electrons

F

In superimposition dating techniques, items that are found at lower strata are younger.

F

The best dating technique for recent organic material is K/Ar dating

F

The crest on the top of the typical robust australopithecine skull is known as the compound temporal-nuchal crest.

F

We are 100% confident that species such as Sahelanthropus tchadensis and Orrorin tugenensis were bipeds.

F

occipital torus

H. erectus

As we saw in the film, Ape to Man, Piltdown Man was initially accepted as a human ancestor because it fit the preconceived notion that

Large brains evolved first

Neandertals needed a lot of calories to function on a daily basis. We know that they met their caloric needs by eating a lot of

Meat (even possibly cannibalism) large fauna and marine resources

Johan Fuhlrott

Neandertal skullcap

Which was the oldest tool industry found in Africa?

Oldowan

England

Piltdown skull and mandible

Eugene DuBois

Pithecanthropus (Homo) erectus skullcap

Indonesia

Pithecanthropus (Homo) erectus skullcap

The "carrying hypothesis" for the origin of bipedality is problematic because

Some apes use facultative bipedalism and carry things for short distances, so it would not be the only reason to walk upright exclusively.

Australopithecines only lived in Africa.

T

Stable carbon isotopes can tell us whether an ancient habitat was forest, grassland, or desert.

T

bipedal locomotion makes humans unique in the animal world

T

Which skeletal feature of Ar. ramidus indicates that this species was capable of bipedal locomotion?

a flaring illium

Biological profile

age, sex, ancestry, height/weight, and disease/trauma

Au. garhi is a good candidate for the Homo ancestor because of its timing and location, limb proportions, and

association w/ tools

hominid

bipedal ape

Another name for a "supraorbital torus" is

brow ridge

Advantages of AR Theory

emphasizes AMH competitiveness, explains relatively uniform morphology seen in humans today around the world, AMH spread around world and outcompeted others, which would explain basic skeletal homogeneity of Homo sapiens both cranially and postcranially

Advantages of MRE theory

emphasizes human gene flow and explains regional variation, AMHs interbreed and share culture, regional variation explained because different pockets of humans evolved in situ with local environmental conditions, fossils show transitions and archaeology shows shared tool industries between AMHs and Neandertals, no evidence for an abrupt takeover in fossils or archaeology and Neandertals share DNA with Eurasians -seems feasible b/c: accounts for regional continuity, have less genetic diversity than chimpanzees (indicating we're a young species)

stable carbon isotopes

give hint about habitat and plant types of past - can be measured from bones of animals; 3 different types created by plants depending on their photosynthetic pathway (shrubs = C3 pathway, grasses = C4 pathway, arid environment plants = CaM pathway) ---> investigate which isotopes animals ate, and thus, what general habitat the animal lived in

Australopithecus africanus had derived skull features compared to A. afarensis including

larger brain and smaller teeth

The transition from the australopithecines to early Homo demonstrates

less of a reliance on chewing musculature

provenience

location in time and space (or can't determine how old it is)

One feature of Ardipithecus ramidus that indicates this species probably spent time in the trees is

long flexible fingers, short thumbs, mobile wrist and divergent hallux

Au. afarensis was not constrained by the need to give birth to large-brained babies. For this reason, its pelvic morphology may indicate __________ advantageous bipedal walking compared to modern big-brained humans.

more

Retromolar space

neandertal

occipital bun

neandertals

Assimilation Model

proposed that accept an origin of AMH in Africa, but consider that during spread of modern humans around the world they interbred with populations that they encountered -some level of African influence w assimilation most probable (an African origin WITH interbreeding)

Dating Techniques

relative dating (superposition, biostratigraphy, chemical tests), absolute dating (radiometric dating, K/Ar dating, electron traps [thermoluminescence, electron spin resonance])

Archaic Homo sapiens

-600-500 kya -increased brain size 1200 cc, more parallel cranial vaults, less prognathism, less post-orbital constriction, rounded occiput (back of skull) -retained some ancestral traits: large faces, inflated cheeks, supraorbital torus (brow ridge), sagittal keel, occipital torus, lack of chin ---> = "archaic" -widespread: Africa, Asia, Southeast Asia, Europe -Archaics in Africa: Bodo (skull from Ethiopia, 600 kya, 1300 cc, scalped), Kabwe (skull from Zambia, 125 kya, 1280 cc, retained ancestral traits: huge supraorbital torus, occipital torus, sagittal keel,huge teeth, associated w/ Acheulean tools (normally associated w H. erectus), but very late we see Levallois Flaking (a neandertal technique) -Archaics in Asia: Dali, Maba, Jinniushan, Yunxian, Narmada skull, Ngandong site

Early Stone Tools (2.5 mya)

-Au. garhi found w/ associated stone tools and butchered antelope bones, however, Homo habilis is traditionally known as tool-maker -first tools discovered at Olduvai Gorge (dating to 1.8 mya), hence tool tradition = Oldowan Tools -later discoveries found tools dating back to 2.5 mya -earlier tools found at Middle Awash in Ethiopia and are associated w/ Au. garhi - tools very primitive (stones w/ flakes knocked off): material used: basalt and quartzite

Raymond Dart

-Australian neuroanatomist working in South Africa and med student brought him Taung Child (most of a face, mandible, and half brain endocast) from Taung lime works site -junvenile; ~3 yrs. old -450 cc brain (comparable to gorilla) -named Australopithecus africanus (southern ape of Africa) -Evidence: 1. canine - wearing from the tip and no evidence of honing 2. foramen magnum - directly below skull 3. human-like brain - pattern of brain organization 4. Not ape ecological zone - open savanna environment, not tropical forest -criticisms: went against prevailing ideas of human evolution that brain expansion came before bipedalism, human evolution assumed to have occurred in Europe or Asia (NOT Africa), expected human-like ancestor not ape-like ancestor; fossil was far too young to be a human ancestor (evolved relatively recently), couldn't base entire species on one juvenile

Glacial & Interglacial Periods [indicated in fossils]

-Oxygen isotopes (16O and 18O) that can be observed in shells of marine invertebrates to see which it has more of - more 18O = glacial period (colder); more 16O = warmer periods -Reveals temperatures of past and relates to ocean levels, which are lower when much of the water is locked up in glaciers (during ice ages) and oceans levels rise as glacial ice melts

Australopithecus africanus (3.5-2.0 mya)

-South Africa -derived skull and dental traits compared to Au. afarensis (reduction in cranial cresting, canine size, prognathism, loss of diastema, larger brain (450-550 cc), & more consistent w parabolic dental arcade) -postcranium similar in size and morphology with Au. afarensis

Sahelanthropus tchadensis

-The earliest pre-australopithecine species found in central Africa with possible evidence of bipedalism -found in 2002, in Chad, Central Africa -320-380 cc -flat face, massive brow ridges, small brain, small non-honing canines (lacking canine/first premolar, or C/P3 honing complex), lacking diastema (space between the teeth for canine of opposite jaw to fit) -foramen magnum in a more inferior position, but skull crushed so impossible to know -still debated whether or not it is a hominid, and can't know for sure without indication of type of locomotion

Neandertal Behavior

-[Krapina in Croatia] bones processed like animal bones: 2 main interpretations of behavior are A) group was cannibalistic and bodies were being butchered for meat OR B) practiced some kind of reburial or mortuary technique -evidence for care of elderly (Shanidar in Iraq) -Mousterian Tools (characterized by Levallois flaking technique): Middle Stone Age (Africa) or Middle Paleolithic (Europe) -Neandertals at St. Cesaire (France site) associated w Chattelperonian tools (usually associated w AMH and Upper Paleolithic) -Tools: more evidence of shafting of spear points and more varied tool types, more blade surface per amt. of stone, evidence of retouching, use of softer materials; -Levallois Flaking Technique shows manufacturer had an image in mind of what tool should look like and had a procedure to make the tool consistently -Moldova in Ukraine - circle of mammoth bones; hearths; shelters, burial of dead and use of grave goods -interbred with modern humans and couldn't have been separate species

antemortem

-changes that occur before death; indicated by evidence of healing or bone remodeling (scar tissue)

Neandertal Postcranial Morphology

-characteristic morphology influenced by cold climate of glacial Europe and harsh living conditions -robust w/ thick long bones (wide) -short distal limb segments, limb proportions typical of modern populations living in colder climates -damage to skeletons w a lot of head/neck injuries likely from hunting injuries -most right-handed and exhibited laterality like pro tennis players - likely from thrusting spears -highly carnivorous

Debate: Hunting vs. Scavenging (early Homo)

-were ancestors hunting prey themselves or butchering carcasses left by large carnivores? -can get hint of whether ancestors hunted or scavenged by whether stone tool marks are on the meaty parts of bone (like thigh) or the less meaty parts (like ankle) b/c carnivore would eat meaty parts and therefore scavengers would likely go for parts untouched (leaner parts, such as bone marrow)

***Splitting

-would divide early Homo into 2 or more species -necessitates figuring out relevant morphological criteria and being consistent with how fossils are divided -some have divided material using different aspects of cranial morphology w/ discordant results (i.e., not consistent between groups); only thing that's consistent in any splitting scenario is that 1470 and 1813 never end up in the same group ---->(For this course:) -ALL material from Olduvai Gorge and small gracile forms from Koobi Fora (including 1813) = Homo Habilis -large forms from Koobi Fora (including 1570) are Homo rudolfensis

K/Ar dating is an example of

A radiometric dating technique

We have good evidence for obligate bipedalism by the time we see A. afarensis, including Lucy, in the fossil record. Compare the A. afarensis femur and tibia, pelvis, and sacrum to those of modern humans and chimpanzees. Describe three features (1 from the femur and tibia combined; 1 each from the sacrum and pelvis) that indicates Lucy and her species was bipedal. Pick one of these features and explain why it is an indicator of bipedality. Be specific and reference your lessons or textbook for correct terminology for each feature.

First, the femur is angled away from the midline, which indicates weight distribution that is consistent with bipedal locomotion. In addition, the tibia is wider near the knee, which also supports the likelihood of bipedal locomotion. Next, the sacrum is broad. Lastly, the pelvis, which is the strongest indicator of Lucy's bipedality, is bowl-shaped with ilia that are strongly flared and laterally facing. To elaborate on the pelvic characteristics, the pelvis is bowl-shaped in order to support the viscera during bipedal locomotion. In addition, the ilia are laterally facing, which is necessary for bipedal locomotion, which requires this arrangement for appropriate muscle attachments for the swing phase of bipedal walking.

Homo erectus

-1.8 mya fossil record from East Africa find multiple hominid morphologies: Au. boisei (robust australopithecine), Homo habilis, and Homo rudolfensis (highly variable early Homo), and Homo erectus (bigger-brained, smaller-faced cousins of early Homo species) - all lived at same place during same time, but only H. erectus persisted ("evolutionary winner") -1.8 mya - 300 kya -2 main differences: larger brain (980 cc avg.); smaller face and teeth -stage of human evolution between early Homo groups and "archaic" Homo sapiens -earliest evidence found in Africa: Kooba Fora in Kenya, Olduvai Gorge in Tanzania, Swartkrans in South Africa -first hominid to migrate out of Africa (to Asia & Europe): b/c glacial action; lived during Pleistocene primarily, which was last major ice age so glaciers advanced and revealed land bridges - traveled quickly to Southeast Asia -different tool culture: Acheulean hand axe

Eugene Dubois

- Dutch anatomist surgeon who wanted to find missing link for idol Ernst Haeckel -found specimens from Southeast Asia (Central Java) -found skullcap from Solo River -Trinil 2, Trinil 3, Pithecanthropus (ape-man) erectus, Trinil 1 (teeth)

Petralona Skull

-1230 cc, mosaic features: long broad face, broad nose w broad interorbital distance like Neandertals, long low cranial vault, large nuchal area w a torus like H. erectus -interpretations: mosaic of Neandertal facial features combined with more erectus-like vault morphology (intermediate between the 2 groups)

Australapithecus afarensis (3.9-2.9 mya)

-2 sites: Hadar in Ethiopia (Lucy) & Laetoli in Tanzania (preserved footprints) -Lucy (AL 288-1) - AL = afar locality; skeleton 40% complete and demonstrates mix of derived and ancestral traits (ex: long arms w humerofemoral index of 85) -Laetoli footprints: fossilized in volcanic ash dating 3.6 mya and thought to have been made by 3 individuals - big toes adducted, estimated height is short (tallest 4'9'') -Dikika in Ethiopia: remains of 3 yr. old girl dating 3.3 mya - evidence indicates spent time in trees: scapulae shaped like a gorillas and phalanges were curved -->MORPHOLOGY: -Teeth - maxillary teeth (upper jaw) were intermediate between earlier and later species; canines smaller than living apes, but still sizable compared to AMH; had diastema; dental arcade was parallel (rather than parabolic as in AMH); molars large and enamel thick, indicating diet of difficult to chew foods -Cranium - skulls quite primitive; 400-500 cc; subnasal prognathism (snout); crests of skull similar to chimps: sagittal (top of skull along sagittal plane) and compound temporal-nuchal (from sides of skull to back), related to chewing and muscle attachments -Pelvis and Legs - obviously from biped; ilia strongly flared, laterally facing, and bowl-shaped; sacrum broad, pubis shortened; knee is valgus (away from midline), and are longitudinal arches in feet; however... long curved fingers and toes, short legs and long arms ---> 2 main interpretations of pelvis interpretation or mosaic morphology: 1. Stony-Brook Camp - active selection to maintain. ape-like morphology and still spending significant amt. of time in trees; pelvic morphology interpreted as being LESS efficient for bipedal locomotion b/c orientation of iliac blades would've necessitated a flexed hip/bent knee walking posture 2. Lovejoy (Kent State) Camp - they were superbipeds b/c not constrained by having large-brained babies so free to be better adapted to bipedalism; arrangement of pelivs and femora more advantageous compared to AMH; ape-like characteristics just evolutionary "hold-overs"; features more important for walking selected first -->QUESTION OF SEXUAL DIMORPHISM: -fossils show range of body sizes; largest seems to be twice the size of the smallest -some interpret as male/female sexual dimorphism, but would be higher than any other primate -many intermediate size fossils; no way to distinguish gender -possible male/female sizes are quite variable w overlap like AMH -large sexual dimorphism would indicate intense physical competition between males, but lower sexual dimorphism would indicate greater cooperation among males, and would make sense w reduced canine size in early hominids

Ardipithecus

-2 species: Ar. ramidus & Ar. kadabba

Ardipithecus kadabba

-5.8-4.4 mya (on earlier [5.8] side) -scant remains (difficult to determine locomotion) -more primitive with larger canines

Pleistocene Technology

-typical technology of H.erectus -Acheulean hand axe characterized by bifacial retouch; tools sharp on 2 edges, and were retouched or sharpened when they became dull -made of better materials than Oldowan and were standardized to all look same -Oldowan + Acheulean tool technologies = Early Stone Age or Lower Paleolithic -represents a period of stasis for 1.5 million years -possibly first to make art - figurines

Match the characteristic with the fossil population/species most often associated with it. You may use each answer more than once, but there is only ONE correct answer for each.

- Widest part of skull is very low: H. erectus - Huge premolars and molars: Robust Australopithecines -Large nose: Neandertals -Flaring cheeks: Robust Australopithecines -Midfacial prognathism: Neandertals

Ardipithecus ramidus (Ardi)

-complete skeleton -found in Aramis, Ethiopia -5.8-4.4 mya (on later[4.4] side) -ape-like features: small molars, thin enamel, arms for climbing, opposable hallux -hominid features: bipedal pelvic shape, small canines, more inferior foramen magnum -300-350 cc -prognathic face (has snout) -minimal canine dimorphism, but robust canines -molar enamel thickness between humans and chimpanzees, indicating omnivorous or frugivorous diet -hands and feet adapted to climbing; hands have long flexible digits, short thumbs, mobile wrists (not adapted to knuckle-walking); foot has divergent hallux and slightly elongated digits (helped w climbing trees), inflexible midfoot and toe-off using second toe, indicating Ardi was capable of bipedal locomotion -pelvis = most definitive anatomical feature: iliac blades are short, broad, and flaring => indicates bipedal locomotion -great sciatic notch, and an anterior inferior iliac spine, which are found only in bipedal apes -lower pelvis more primitive (more like chimps than humans) - ischia indicate an orientation of hamstrings for climbing, and pubis is elongated like modern nonhuman apes ----ilia demonstrate bipedalism while lower pelvis is more primitive -paleoecology is woodland, not savanna (remains found in woodland)

Australopithecus anamensis (4.2-3.9 mya)

-discovered by Maeve Leakey at Kenyan sites of Kanapo and Allia Bay -teeth intermediate between Ardi and Au. afarensis: --primitive dental features: U-shaped dental arcade (parallel rows of teeth) and large anterior teeth; --derived dental features: large molars, thick enamel, small canines (but some evidence of honing); size variation in teeth and mandibles, indicating sexual dimorphism -locomotion: tibia shows definitive bipedal features such as enlarged proximal end (robust platform) and a proximal morphology (distinctively similar to AMH) and relates to articulation between tibia and femur indicating an angled femur -habitat: riparian forest (riverine) w areas of woodland or grassland -most fossils damaged by carnivores -morphology overall represents mix of derived and ancestral features; very similar to Au. afarensis, but is more primitive so it is a separate species

Australopithecus garhi (2.5 mya)

-discovered in Middle Awash region of Ethiopia -450 cc brain -prognathic face -large canines -sagittal crest -teeth were large front to back, and had some cranial cresting -humerofemoral index 80 (derived limb proportions) -associated w stone tools and animal bones - used stone tools to butcher antelopes --> therefore, large brain isn't required for tool use and manufacture -possible candidate for Homo genus ancestor

Piltdown Forgery

-fit British view of evolution that large brain thought to have evolved first -mandible was ape-like - was from an orangutan w teeth of jaw filed down to match wear on skulls and bones stained to match each other -4 decades after discovery hoax was revealed -shortly after, redemption of Dart's theory and ideas (1950s) - more fossils like Taung found and Les Gros Clark & Robert Broom supported Dart

Australopithecus

-found in East and South Africa -parabolic dental arcade (like AMH) -larger brain (~480 cc) -split into 2 lineages: robusts (sometimes placed in genus Paranthropus), and non-robusts -4.2 mya origin and persisted until 1 mya -coined by Raymond Dart after finding Taung child skull

Orrorin tugenesis

-from Tugen Hills of Kenya -discovered in 2000 -from 6 mya -teeth and various postcranial bone fossils -body size similar to modern chimpanzee and is adapted for climbing -proximal femur and pattern and thickness of bone hint weight distribution of animals and discoverers believe femur indicates that it walked upright, but isn't conclusive b/c don't have other bones

Atapuerca 5

-from cave Sima de los Huesos dates to 500-600 kya -big nose, midfacial prognathism, inflated cheeks, arched supraorbital torus, large cranial capacity (1390 cc), retromolar spaces

Lumping

-higher degree of morphological variation -fewer branches in family tree (streamlined number of species), but each species is highly variable -would have to find a way to account for Homo habilis variation in Koobi Fora material (1813 & 1470) - some say sexual dimorphism, but that would be very extreme

Evolutionary trends that set Homo genus apart from their Australopithecine predecessors

-increase in brain size (680 cc avg.) -more rounded skull -smaller, less prognathic face -reduced jaw musculature -smaller teeth (especially molars and premolars) -thinner enamel -parabolic dental arcade (only some Austroliphs had) -decrease in sexual dimorphism -more consistent tool users

Steinheim Skull

-intermediate between H. erectus and later archaic H. sapiens

Anatomically Modern Humans (AMH)

-rounded, vertically-sided cranial vault w a high maximum width, and no significant brow development -face and teeth reduced in size and there's a prominent chin -cheeks have a canine fossa (unliked inflated cheeks of Neandertals) -postcranium less robust and long bones are longer and thinner -more advanced culturally

Homo erectus Morphology

-sagittal keel (on the top of head like bottom of boat) -long, low cranial vault (no high foreheads) -supraorbital torus (brow ridge) -supratoral sulcus (dip in bone above brow ridge) -alveolar prognathism (face juts forward in region of teeth) -no chin (receding mandibular symphysis or front of mandible) -teeth smaller than earlier Homo but larger than AMH - shovel-shaped incisors in certain geographic areas --->cranial and dental features reflect greater tearing and biting w/ incisors and canines and less heavy chewing w/ molars -body size increased -increased sexual dimorphism than AMH but. less than preceding species -widest part of cranium was low on skull (shape of skull from back is pentagon)

Absolute Dating Techniques

-tells you an actual date +/- a margin of error 1. Radiometric Dating - radioactive isotopes decay into non-radioactive isotopes at known steady rates (ex: radiocarbon dating - directly dates organic material using half-life) 2. K/Ar Dating - used to date volcanic rocks or minerals; radioactive K in volcanic rock decays (at known rate) once lava or ash cools 3. Electron traps - when buried in soil, object will incorporate radioactivity from the soil in the form of electrons into its crystalline structure, and these electrons fill up "traps" in structure, and can be used to date based on how full traps are -used to date "tricky" sites that fall outside range of radiocarbon dating and below range of K/Ar dating -a) thermoluminescence (TL) - trapped electrons emit light when heated - amt of light can be measured -b) electron spin resonance (ESR) - dating of tooth enamel

The oldest material that can be reliably dated using the radiocarbon method is how old?

40 kya

Early Homo Fossils at Olduvai Gorge (Tanzania & Koobi Fora, Kenya)

1. 1960: -Louis and Mary Leakey found cranial and mandible bones here; Au. boisie had already been discovered here but these were unlike OH5, but specimens dated to same time (1.75-1.85 mya) -bones indicated increased brain size and smaller teeth & face compared to Australopithecines -Homo habilis ("handyman") named in 1964 - interpretation criticized b/c believed teeth were in range of Australopithecines and brain estimates unreliable b/c missing pieces of OH 24 skull 2. Early 1970s: -Richard Leakey working at Koobi Fora (Kenya) found mandibles and isolated teeth dating back to 1.8 mya that were smaller than range of Australopithecus and were considered to be Homo -small brain sizes of 510 cc (ancestral trait), but also small face and teeth (derived traits) -morphology represented by skull KNM-ER 1470 w/ large brain (752 cc) and from 1.75 mya - more specimens w/ larger brain case found at this site -problem w/ specimens: show derived trait of much larger brain, but also show ancestral trait of a huge palate and large teeth, also larger face (any Homo supposed to have small teeth); morphology unusual and only aspect that's Homo-like is large brain size --->controversy over this species based on 2 skulls: KNM-ER 1470 & KNM-ER 1813 - possible to have been more than one species living at this time and location 3. 1986: -Donald Johanson & Tim White surveyed Olduvai Gorge for new material and found skeleton, which was assigned to H. habilis --> OH 62 because its date - 1.8 mya, location, & dental morphology -humerofemoral index = 95 - more ape-like than Au. afarensis and arms almost. as long as legs

Modern Human Hypotheses

1. African Replacement Theory (AR) - modern humans recently speciated from earlier hominid species; AMH already a new species before leaving Africa, then migrated to other areas and replaced archaic populations; 1st appeared in Africa and abrupt change in morphology, technology, and behavior when AMH arrived to replace archaics around world; no regional continuity in morphological features outside Africa and all morphological features must be traceable back to Africa; wouldn't expect to see any genes between AMH and archaic populations 2. Multiregional Evolution (MRE) - H. erectus migrated out of Africa, and ever since then there was gene flow b/c no population was isolated afterward; would've allowed some regional features to develop like shoveled incisors in Asians, and Neandertal features in Europe; transitional fossils should be all over the world; evidence for regional continuity in morphological features; predicts shared tool technologies between AMH and archaics, and genomes of AMH and archaics would overlap; predicts no consistent geographic patter of appearance in modern humans; polytypism of modern humans is same today as it was in past

Robust Australopithecines (genus: Paranthropus)

1. Au. aethiopicus (2.7-2.5 mya) -East Africa, 410 cc, KNM-WT 17000 (Black Skull) -extreme cranial cresting (heavy chewing apparatus), subnasal prognathism, small brain, sagittal crest, compound temporal-nuchal crest, flaring zygomatic arches -huge post-canines (premolars and molars) and small incisors and canines -no postcranial remains so don't know about body 2. Au. boise (2.3-1.2 mya) -East Africa, 500-550 cc -Leakey's excavations at Olduvai Gorge (1930s) -sagittal crest, flaring zygomatic arches, small incisors and canines, huge premolars and molars -"nutcracker man" -OH5 in 1960s - first hominid to be radiometrically dated: ~1.85 mya -no postcranial remains 3. Au. robustus (2.0-1.5 mya) -South Africa, 500-550 cc -cranial cresting, huge post-canine teeth, small incisors and canines, large chewing muscles, flaring zygomatics -no postcranial remains -SK 54 nicknamed Leopard Lunch - leopards may be reason why hominids found in caves because drop victims there bc they eat and store carcasses in trees which grew above cave shafts --->2 problems for paleoanthropologists: 1. if cave ceiling collapses, bones get crushed and distorted; 2. bones found at lower strata than they actually lived so date interpretations mistakenly older ---Overall, robusts weren't different in body size from others, just were more robust in skulls and teeth; robust features = adaptation for chewing, probably nuts or seeds, which could've been fallback foods

Hypotheses for Bipedality

1. Carrying - perhaps long-distance carrying of objects was key, and long-distance travel w bipedalism was more energy efficient -apes and gorillas can walk short distances bipedally 2. Ecology & Energetic Efficiency - says forests dwindled so hominids needed to travel between patches of forest for food and shelter --> energy saved would be used for finding more resources, investing more in offspring and reproductive success, and passing on genes for anatomical changes associated w bipedalism; - dont know how efficient earliest bipeds were 3. Hunting - came down from trees to hunt more efficiently -no evidence of hunting w earliest bipeds; chimpanzees hunt effectively as quadrupeds 4. Provisioning Hypothesis - early hominids were pair-bonded, and long gestation, growth periods, and lifespans resulted in a need to devote more time to care for fewer young - led to male provisioning, which increased reproductive fitness of both sexes, and increased survivorship rate of offspring; bipedal locomotion would've benefited males for getting food -in early hominids, extreme sexual dimorphism -> non-monogamous mating system; boils down to long-distance transport of food, whether by males or both sexes 5. Thermoregulation Hypothesis - combines known climatic changes in Africa in late Miocene from wet and hot to cool and dry (i.e., expanding savanna) w/ advantages of bipedal locomotion: standing upright reduces SA exposed to solar radiation, increases amt. of wind that body is exposed to to stay cool (in newly forming savannas) ------don't know original driving force behind bipedalism, only know the advantages: freeing the hands and making it easier to cool the body

Bipedal Skeletal Features

1. Head: Inferior Foramen Magnum - directly below (inferiorly to) skull because head is on top (not in front) 2. Spine: S-shaped - has 2 curves instead of one; has lumbar (lower) curve to support weight of the torso 3. Center of Gravity: Middle of Pelvis 4. Pelvis: Broad Iliac Blades - human pelvis is short and broad w broad iliac blades (hips); bowl-shaped and supports viscera 5. Pelvis: Lateral Iliac Blades - iliac blades face laterally (to the side), which has to do w muscle attachments and swing phase of bipedal walking 6. Sacrum: Broad - has to do w reorganization of the pelvic musculature and bones 7. Femur: Angled - human hip broader than nonhuman so femora need to angle inward to keep knees underneath the center of gravity - means theres an angle of the femur => valgus knee 8. Tibia: Robust Platform - body weight carried on 2 legs so knee joint more robust to support greater amt. of weight; thick and platform-like 9. Food: Adducted Hallux - big toe adducted (pulled toward midline) and non-opposable; relatively short and straight toes 10. Foot: Longitudinal Arch - human foot built for springy steps and using energy efficiently as we propel ourselves forward on 2 feet; arch helps convert potential energy (compression of arch) to kinetic energy (when we push off with our toes)

5 Principles of Stratigraphy (study of the distribution of Earth's layers)

1. Superposition - younger geologic layers found on top of older 2. Original Horizontality - layers of Earth were originally laid down parallel to Earth's surface (flat), and any non-horizontal layers must have been altered after 3. Lateral Continuity (Lithostratigraphy) - states that geologic layers extend in all directions; allows for comparisons across wide spaces even if geologic layers are interrupted 4. Cross-Cutting Relationships - says that a geologic feature must exist before you can cut across it (ex: a candle being inserted into a layered birthday cake where the candle is the youngest layer - interrupted existing layers) 5. Faunal Succession - tracks the series of animal fossils through geologic layers w the deeper fossils being the older ones (----> each layer may have a particular fossil that's very common and then may signify a certain layer and thus a certain period of geologic time => index fossils)

Phases of Bipedal Walking ("controlled falling")

1. Swing Phase - propulsive push from the big toe 2. Support Phase - bodyweight supported by one leg 3. Touch Down - stopping of swinging leg and heel strikes ground 4. Toe Off - cycle continues w other leg

Early Archaics in Europes

2 Categories: 1. Early (late erectus/archaic H. sapiens) - Homo heidelbergensis or antecessor 2. Late (Neandertals) - H. neanderthalensis or H. sapiens neanderthalensis

What to do with Early Homo?

2 solutions: 1. Lumping "early Homo" fossils into one species OR 2. **Splitting them into 2 or more species

Climate and environment changes at the end of the Miocene potentially influenced our ancestors' shift from quadrupedal to bipedal locomotion. How would you describe these changes?

A significant cooling of the earth occurred in the late Miocene, which caused some areas of the tropical forests of Africa to dry out and and become savanna grasslands. At some point the quadrupedal primate morphology shifted to select for features that aid in bipedal locomotion to allow for faster more efficient long distance travel between patches of forest.

Stone tools are part of the lower paleolithic, and systematic stone tool production appears in the fossil record around 2.5-2.6 million years ago. These early stone tools are called Oldowan. If you look at the "Time line of human evolution" in the back cover of your textbook, figure 10.32 (Hominin Lineages), or compare the dates of fossil specimens from the lessons and your textbook, you will notice that there are several named species alive at 2.5 mya. Provide a list of species that were present at around 2.5 mya. Which of these species is most likely to have first made Oldowan tools? Why? For what purposes might the Oldowan tools have been used?

List of species present around 2.5 mya: Australopithecus garhi, Australopithecus aethiopicus, Australopithecus africanus, and Homo habilis. Homo habilis is most likely to have first made Oldowan tools because they were found at the same site, which was concluded by the Leakeys who coined the name 'Oldowan Complex' based on their work at the excavation site at Olduvai Gorge. However, there is evidence of tool use that dates back to 3.3 mya. Oldowan tools were likely used for food processing such as removing meat from animals, smashing bones to access protein-rich marrow, or even possibly for digging into the ground for accessing termite mounds or edible roots.

The stratigraphic principle of cross-cutting relationships says that a geologic feature must exist before you can cut across it

T

There is debate about how much sexual dimorphism existed in Au. afarensis. Some scientists think this species had a higher magnitude of dimorphism than any living primate species. Other scientists think that males and females were highly variable and overlapped in size as they do in modern humans.

T

You must know a fossil's provenience in order to properly date it

T

Raymond Dart

Taung skull and endocast

South Africa

Taung skull and endocast

Much of the information presented in the film, Ape to Man, is our best guess of how these extinct human species would have lived. The film makers took some artistic license with some of the details. Which of the following could NOT easily be determined from the fossil remains themselves, and would have had to have been "extrapolated"?

That Homo erectus had developed sweat glands

Compare the skulls and dentition of Australopithecus afarensis , a gracile australopithecine, to both the modern human and chimpanzee. Look at tooth size, dental arcade shape, prognathism, and brain size, or any other traits you read about in the lesson.

The brain size (small) and the canine size (large) are more primitive and ape-like. The maxillary teeth are an intermediate between earlier and later species (canines are smaller than living apes, but larger than later hominids). They also exhibit a diastema between the lateral incisor and canine, which is lacking in modern humans. The dental arcade is parallel, which is characteristic of apes rather than humans (parabolic). In addition, their molars are large. Lastly, the skull exhibits a more pronounced zygomatic arch. Overall, for these reasons, I believe that A. afarensis is more similar to the chimpanzee than to a modern human.

The Pithecanthropus (Homo) erectus femur from Java showed evidence of a severe break and subsequent healing during the lifetime of the individual. The interpretation of this healing was what?

The individual lived with a family who helped him survive despite the injury

Compare the skulls of the robust australopithecines ( A. robustus, A. boisei, A. aethiopicus) to the gracile australopithecines A. afarensis and A. africanus. Describe two morphological features found on the robusts that we do not see in the gracile specimens. What do you think these features indicate about the robust australopithecines' diet?

Two morphological features found on the robusts that are not seen in the gracile specimens are huge post-canines (premolars and molars), and flaring zygomatic arches. These features indicate a heavy chewing apparatus, which means that the diet of these robust species likely consisted of nuts and seeds that required serious force to process for consumption. As mentioned in the lecture notes, this could have been a "fallback" diet because the preferred food source was sparse or unavailable.

In the electron trap absolute dating technique known as thermoluminescence, when does the clock start measuring the age of the object?

When the object is heated

Which of the following most likely indicates hominid hunting (versus scavenging) in the fossil record?

stone tool cut marks underneath carivore tooth marks of meaty parts of the animal.

Paleontology

study of prehistoric life; can see what animals lived and died during timeframe

Europeans of the early 1900's considered Africa ______ to be the site of human evolution.

too primitive

What is one reason that we have a difficult time pinpointing the dates of fossil sites in South Africa?

the provenience is not well established for many fossils discovered over a century ago