ANT3514C Exam 3

Late Miocene Hominins in Africa

last common ancestor of humans and African apes

Shrinking patches of rainforest

lead to bipedalism

two views on evolution of humankind in early 20th century

locomotion first vs brains first

Which of the following is not true about Homo naledi?

Its braincase is smaller than that of Homo erectus TRUE ANSWERS: -The postcrainia indicates that it spent time in the trees -It has yet to be dated - It has only slight post-orbital constriction -The postcrainia indicates that it was well adapted for bipedalism

Two views on Au. Afarensis and role or arborealism

Midwest Museum Group -Au. afarensis was adapted to bipedalism only -climbing features were leftovers of an arboreal past (facultative climbers but not selectively-active aspect of ecology) -selection of many agents of change, other agents have larger relative roles -evolutionary change is hard; form takes primacy function responds to form -structuralist perspective Stony Brook Group -Au. afarensis was adapted to both walking and climbing (ALL features are adaptations) (obligate climbers) -selectively active adaptations of arborealism -selection continually very active, other agents minimized -evolutionary change is easy; function takes primacy form responds to function -functionalist perspective

Cooking allows individuals to take in more calories with less food by breaking down cell walls which makes food easier to digest.

True

Proconsul

ape like dentition but monkey-like body

locomotion first theory (correct)

ape-> bipedal ape-> intelligent bipedal ape-> human

brains first theory (incorrect)

ape-> intelligent ape-> bipedal intelligent ape-> human

If Paranthropus boisei and Paranthropus robustus are both descended from Paranthropus aethiopicus, this would make the robust australopiths a true ______.

clade

Hadar Stratigraphy

fossil designations indicate specific discovery site; Lucy is labeled Afar locality

hominid (old term)

hominin (new term)

modern (clade-based) taxonomy

hominin=bipedal ancestors to humans -hominid=humans, bipeds, and African apes -hominoid=all apes

Paranthropus boisei

-1959 Mary Leakey -robust australopith- first named zinjanthropus boisei -very large cheek teeth -small anterior dentition -a human cuisinart -dimorphic

Lucy (australopithecus afarensis)

-1974 discovery by Johanson -40% complete skeleton -all one individual -mature adult -one meter tall -one bone recently identified as that of a gelada baboon (can never assume things are reported correctly)

Laeotoli, tanzania

-1978 discovery of footprints -3.6 mya -fossils similar to Hadar finds

Australopithecus bahrelghazali

-1993 -Chad -first hominin outside of East Africa rift valley -3.4-3 mya -mandible fragment and P3 -suggested derived bicuspid P3 and divergent tooth row

Australopithecus anamensis

-1994 by Meave Leakey -4.2-3 mya (oldest australopith) -2 sites near Lake Turkana (Allia Bay and Kanapoi) -cranial and postcranial remains -postcranial: advanced biped, sexually dimorphic -cranial remains: between ardipithecus and later australopiths

Australopithecus garhi

-1999 -asfaw, White and colleagues -2.5 mya Ethiopia's middle awash region -garhi=surprise -cranio-dental remains and postcranial remains -cranium: small brain, prognathic face, very large teeth -postcranium: long legs, long forearms, less than 5 ft tall -antelope remains from nearby site with cutmarks -whether garhi or another hominin is responsible; meat/marrow eating at early date--hallmark in human evolution (technology, diet)

Kenyanthropus platyops

-1999 Meave Leakey -flat faced man of Kenya -3.2-3.5 mya -west turkana -contemporary with Lucy -new genus-controversial -not in text

Hadar, Ethiopia

-A.L. 129 discovered in 1973 by Johanson -3.4 mya key bipedal features: valgus, femoral condyles modified, and patellar notch raised -found more fossils in 1974, including Lucy and First Family

Gracile Australopith list

-Australopithecus africanus -A. afarensis -A. anamensis -A. bahrelghazali -generalized jaws and teeth

Australopiths (East Africa)

-Australopiths related to Paranthropus (Kenyanthropus also related but not in text) -4.2-1 mya -all bipedal -large teeth, thick enamel, big chewing structures -chimp-sized brains -key countries: Ethiopia, Kenya, and Tanzania

Paranthropus Robustus

-Broom 1938 -2-1.5 mya -tiny anterior dentition -very large molars -heavy chewing muscles -key sites include: swartkrans and kromdraii

Piltdown Gravels

-Charles Dawson -Sussex, England -two human skull fragments found 1908 -1912 reported find to Arthur Woodward -became Eoanthropus dawsoni

Early discoveries in South Africa

-Dart recieves a crate of bones from quarry at Taung -finds one skull special -Taung Child (first African hominin discover 1924) -included endocast, mandible, and skull -key spot for discoveries

Olduvai Gorge

-East Africa -stratigraphic sections; formations contain members

Chorapithecus

-Ethiopia -10-11 mya -new species of African ape -gorilla sized -adapted to harder food

Omo, Ethiopia

-F Clark Howell -key site north of lake turkana -usno and shungura formations -A. afarensis -P. aethiopicus type specimen

Nakalipithecus

-Kenya -10 mya -body size: large, about size of female gorilla -hard object diet -likely terrestrial -likely African origin and moved to Europe -more primitive than Ouranopithecus

Australopithecus sediba

-Lee Berger 2010 -1.98-1.7 mya -cranial and postcranial -adults and juvenile -small brain 430 cc -long arms -traits of Homo: dentition, broad frontal bone, derived face, derived pelvis

Leakey family

-Mary and Lewis (richard, meave, and louise) -1930s -Olduvai Gorge significant discoveries -Mary discovered Zinj in 1959 (paranthropus boisei)

Homo habilis

-Oluvai Gorge (beds 1 and 2) -2-1.6 mya Leakey et al -handy man -tool association -passes "cerebral rubicon"= sir arthur keith set 750 cc as human threshold -reduced molar size -stone tool maker -hand bones robust and prehensile for precision and power grip -adducted hallux -hands and forelimbs indicate climbing and weight support adaptations

Robust Australopith list

-Paranthropus robustus (2-1.5 mya) -P. aethiopicus (2.7-2.5 mya) -P. boisei (2.3-1.2 mya) -specialized jaws and teeth

Piltdown Hoax

-Piltdown man was hoax -1950 -cranium and mandible were from separate individuals -fluorine dating yielded different dates/ages for both pieces -fossil braincase of a prehistoric human -modern orangutan jaw (Pongo) -Martin A.C. Hinton thought to be responsible for hoax -Charles Dawson really responsible (whole academic career built on deceit) -set back 40+ years -was deemed missing link -supported brains before bipedalism theory -also supported more local evolutionary scenario -racial bias towards evolution of intelligence in Britain

Lomekwi

-Pleistocene flintknapping -West turkana, Kenya -archaeological site -recently identified stone tool assemblage near the site where Kenyanthropus platyops was recovered -3.3 mya -in situ stone artifacts occur in spatiotemporal association with Pliocene hominin fossils in wooded paleoenvironment -predates Oldowan tool tradition by 700 ka

Osteodontokeratic Culture

-Raymond Dart's notion of human tool use -based on Makapansghat -bone, tooth and horn -A. africanus fossils associated with fauna -Audreys book African Genesis -C.k. Grain -Taphonomic studies proved it was not a hominin-produced assemblage but they were the hunted and scavenged

Rising Star Cave

-South Africa -homo naledi material found -submerged sediment trap at Malapa site contained homo remains -no clear litho/chronostratigraphy; biostratigraphy used instead

Australopithecus africanus

-Taung Child -Dart 1925 -Robert Broom and John Robinson (sterkfontein and makapansgat) -3-2 mya -high forehead -no brow ridge -flat, orthagnothic profile -decidous teeth; no diastema; smal canines/big molars -gracile build -foramen magnum anteriorly placed; bipedal -endocast 405 cc/450 adult (smaller than human but bigger than chimp) and human shaped neurocranium -key fossils of cradle of mankind

key bipedal features

-anteriorly placed foramen magnum -lumbar lordosis (lower back curved anteriorly while thoracic section is normal and cervical curved) -lengthened lower limbs -enlarged joint surface areas -short/broad pelvis (bowl shaped and rotated laterally for receiving femoral head) -valgus femur angle -realignment of gluteal muscles (chimps dont have butts) -full extension of "locked" knee joint for striding gait rather than waddling gait and standing -arched, rigid platform foot -adducted big toe (hallux) -shortened toes and elongated mind and hind foot

Raymond Dart (1893-1988)

-australian anatomist -chair of anatomy at university in Johannesburg, South Africa -student of Arthur Keith (not fans of each other)

The australopiths consist of two genera: _____________ (called the "gracile" australopiths) and ____________ (called the "robust" australopiths).

-australopithecus -paranthropus

Hominin trends

-australopithecus -> homo -larger brains (encephalization) -smaller dentition

Paranthropus aethiopicus

-black skull -1985 discovery -west turkana and Omo -2.8-2.2 mya -primitive robust australopithecene

Sir Arthur Smith Woodward

-bristish paleontologist -worked with Dawson and others at Piltdown site -recovered 7 skull fragments, corpus of mandible with two worn molars in situ, artifcats and fauna -fauna suggested Plio-Pliestocene age of Piltdown verterbrate assemblage -prepared first reconstruction of the find

Swartkrans

-cave in South Africa -Paranthropus robustus (similar to bosei)

Sterkfontein

-cave site in South Africa

key hominin adaptations

-chewing apparatus dominated by large molars and premolars, thick enamel, small-medium incisors, and non-projecting/non-dimorphic canines -somewhat enlarged and re-organized brain -elaboration of material culture -habitual bipedalism

Eurasia and Africa become attached by late Miocene

-closes Tethys sea and causes period of aridification -drier and more seasonal

Stone tools

-confer an advantage to gaining access to difficult to get to places (bone marow within the medullary cavity of long bones) -bone marrow is rich in nutrients aka brain food

Eonthropus Dawsoni

-dawson's dawn man -dethroned Neanderthals and Java Man from direct ancestry -fauna indicated late pliocene-early pliocene age -woodwards' reconstruction cranial capacity of 1070 cc -several camps did not accept authenticity and/or association of skull fragments and jaw -others did not accept Woodward's reconstruction, including Sir Arthur Keith

When considering early hominin "lifeways" based on evidence collected from fossil sites and assemblages, what can we infer?

-diet -paleobiology -paleoclimate and paleoecology -body size dimorphism

First Family

-discovered in 1975 -200+ hominin fossils -13+ individuals (9 adults and 4 juveniles) -catastrophic assemblage of individuals -3.2 mya

Orrorin (millenium man)

-disocvered 2001 -Tugen Hills, Kenya -6.1-5.7 mya -isolated teeth and postcrania -first Hominin from Kenya -Martin Pickford and Brigitte Senut -small molars with thick enamel (intermediate, in terms of occlusal morphology) -canine large and pointed -cheek teeth smaller -thickish enamel -curved phalanx -femur derived and suggests bipedalism: femoral neck heavier at base like humans apart from chimps; thicker cortex inferiorly than superiorly on femoral neck; obturator externus groove present; elongated femoral neck; well-developed gluteal tuberosity -argued by founders to be more similar to modern humans than Australopiths are based on their dentition and bipedal adaptations; Homo-like dental features led authors to suggest that the Australopiths are not ancestral to humans

paleoecology

-environment context is key to interpreting fossils -must know what types of assemblages you are studying and if they represent the original community of plants and animals

South Africa

-geologically very old and inactive -cradle of humankind characterized by karst cave systems (limestone caves) --little foot

East African Rift Valley

-geologically very young and active -one of three volcanoes that are part of mt kilimanjaro is dormant (Kibo) -snow capped peaks are melting at an alarming rate

traditional (grade-based) taxonomy

-hominid=bipedal ancestors to humans -hominoid=apes

Sir Arthur Keith

-human anthropologist and physical anthro -believed brains first then bipedalism -conservator at hunterian museum -reconstructed Piltdown Man to his liking

hominin bipedalism theories

-idea that tool carrying led to bipedal apes does not hold much weight in terms of fossil and archaeological evidence (darwin believed this but did not have fossils to study) -no evidence for systematic hunting with weapons exists -hominoid orthogrady already supposes foraging from ground-level into the trees (requires bulk of activity in mid-day sun and bipedalism likely occurred in forested areas) -"meerkat hypothesis" -male provisioning -long distance walking --all difficult to test -running after game -tracking migrating herds -sexual display -energy efficient locomotion and staying cool -predator avoidance -aquatic ape hypothesis

"protohominin" characteristics

-incipient, facultative bipedalism -thick enamel -moderate canine reduction -reduced mesiodistal molar length -shallow and thick, robust mandibles -material culture??

Molecular Clock

-late Miocene (12-7 mya) fossil record in sub-Saharan Africa is very poor, a dearth of hominid fossil material -BUT a key time period to explore divergence between humans and our closest cousins, the African apes -molecular clocks are best when used with the fossil record -most studies suggest divergence estimates: --between humans and Pan 5-6 mya --between humans and gorilla 6-8 mya

Robust australopiths

-late Pliocene-early Pleistocene deposits (2.5-1 mya) -East and South Africa -massive molars -flat, broad "dished" faces -poorly known postcranial anatomy -similar in body size to Australopithecus -hard object feeders: sagittal crest, large cheek teeth, flared zygomatic arch, dished face, and extreme postorbital constriction -woodland and open woodland habitat

Sahelanthropus (prob early hominin on line to humans and not gorillas)

-led by Michael Brunet 2002 -North-Central Africa (Chad); one of only two pre-Homo found in Central Africa -7-6 mya -a crushed cranium and isolated jaw fragments -similarities to Graecopithecus, Gorilla: orbit shape, interorbital distance, nasal aperture, cresting, enlarged molars and premolars -similarities to hominini: small, apically worn canines, short basicranium, anteriorly-placed foramen magnum, moderately thick enamel, fairly big brain (320 cc), orthagnathic

If you are a ________, you tend to view all variation as intraspecific variation and so there are few real species represented in your collection. At the other end of the spectrum, if you are a _________, you tend to view all variation as interspecific variation and so there are many species represented.

-lumper -splitter

Australopithecus afarensis

-new species combined hominin assemblages from two sites (hadar and laetoli) -4-3 mya -tall canine and diastema -cheek teeth like A africanus -thick enamel -tooth row shape unlike apes -primitive skull and dentition (P3 has single cusp like Pan) -bipedal like us, ( argued that they climbed as well?) -pelvis more splayed and horizontal -conical rib cage (inverted funnel shape) -long arms, relatively short legs (bones curved) -scapula more similar to arboreal or semi-arboreal apes rather than humans -intermediate proportions between apes and humans -a number of large carnivores existed during the entire evolutionary history of hominins (leopards, lions, and tigers in Old World today are formidable)

the 3 P's

-phylogeny -paleobiology -paleoecology

Dental wear analysis informs researchers about diet because hard foods leave _______, tough foods leave _______, and soft foods leave _______.

-pits -long scratches -nothing

LCA having material culture?

-possibly, but earliest stone tools seem to occur after origins of bipedalism -not all material culture is preserved -non-human primates use tools (chimps use sticks to hunt) -lack of evidence does not mean it does not exist

heat exposure

-quadrupeds more exposure surface area -bipeds are higher off ground where it is cooler and there is a breeze, and body is less exposed to sun

punctuated equilibrium

-rapid divergent speciation -long periods of stasis -gaps in fossil records attributed to rapid change -usually takes place in small populations

teeth and jaws

-ready made fossils -highly heritable (lots of phylogenetic info) -sensitive to selection (offers functional info)

Gracile Australopiths

-reduced brow ridge -protrusive jaw -external auditory meatus -no sagittal crest -temporal nuchal crest gets changed by encephalization

Paranthropus boisei

-robust australopith first called zinjanthropus -very large cheek teeth -small anterior dentition -"human cuisinart"

Robert Broom (1866-1951)

-scottish, trained medical doctor -paleontologist in South Africa -strong supporter of Dart's Taung Child -discovered Plesianthropus transvaalensis (adult form of Taung Child called Mrs. Ples, which was actually Australopithecus africanus)

selection of big brains

-technical intelligence: tool use and extractive foraging -ecological intelligence: complex cognitive maps needed to exploit complex environment -social intelligence: being politically and socially astute with the ability to deceive

defining hominin

-trait used to distinguish us from Pan is bipedalism -to be a hominin must show features of bipedalism -direct: features showing clear adaptations for upright walking (postcranial, especially legs and hips) -indirect: features showing upright posture, but not necessarily upright walking (cranial, spine, arms) = less reliable, more suggestive

Ardipithecus (Ardi)

-two hominin species: ardipithecus kadabba (5.8-5.2 mya) and ardipithecus ramidus (4.4 mya) -both discovered by Tim White and team in Middle Awash, Ethiopia -first thought to be Australopiths -remains of 35 individuals discovered -kadabba: more primitive and ape-like than ramidus; slightly smaller canines; wooded habitat -ramidus: long upper limb, divergent hallux (for grasping during climbing; stiff foot like human suggests inflexibility in grasping but good for bipedal propulsion), hominin-shaped pelvis (greater sciatic notch, anterior inferior iliac spine, angled ischial surface); small canines with wear on tips; no CP3 complex; anteriorly placed formane magnum; small cranial capacity; shortened pelvis suggests bipedalism; mosaic of arboreal and bipedal locomotion; gluteus maximus inserts on femur like humans; no honing complex in teeth and thicker enamel; first molar is single cusped like chimps; opposable hallux and flexible hand with curved phalanges (more arboreal features); brain capacity 300-350 cc like chimps; evidence debated over whether open woodland or more forested due to C3 and C4 vegetation stable isotope evidence; authors believe they are directly related to Australopiths but with more bipedalism and smaller habitat and smaller canines possibilities about Ardi: 1. mostly bipedal human ancestor 2. some-what bipedal chimp ancestor 3. mostly bipedal ancestor to neither 4. not bipedal and likely a chimp ancestor

Loss of CP3 complex

-upper canine fits into the diastema where they slide past P3 -P3 has one cusp in apes -the CP3 acts as a tooth sharpener -prob reduced in LCA --mesiodistal molar length is reduced --hominins have square molars not rectangular like apes

depositional environment types

-volcanic deposits -lacustrine or lake deposits -fluvial or river deposits -cave deposits (typical of South Africa) -fossil soils or paleosols -alluvial fan deposits

Last common ancestor of African apes and Hominins

Africa, about 9-5 mya

tooth enamel

not a good characteristic to use as a shared derived feature (synapomorphy)

bipedalism

not unique to humans, many other animals use bipedalism; but humans are habitually bipedal

LCA locomotion

prob more terrestrial and knuckle-walking than a quadruped or swinging from trees

Dikika, Ethiopia

remarkably well preserved 3 year old child of australopithecus afarensis

Jaw

shape of dental arcade changes with canine reduction and reduced dimorphism (u-shaped Pan to parabolic Homo)

phylogeny

study of evolutionary relationships of organisms; anatomical, molecular, behavioral traits examined in both extinct and extant taxa

mosaic evolution

the piece by piece emergence of a new form; in particular we are interested in becoming human -in the same way a mosaic is made by adding a single part at a time, the tinkering nature of the evolutionary process adds and removes piece by piece -this is how modern humans emerged

In the Paranthropus grade model, Paranthropus robustus evolved from Australopithecus africanus.

true

phyletic gradualism

uniform and slow mode of human evolution

paleobiology

when studying fossil taxa, you want to be conservative in terms of how you interpret the skeletal remains to reconstruct the biology of the taxon in question