anth exam 2

what are the theories associated with the origin/evolution of bipedalism as well as the components seen in the forms of bipedalism used by modern humans

what are the theories associated with the origin/evolution of bipedalism as well as the components seen in the forms of bipedalism used by modern humans

theories of evolution: -may have facilitated transferring food from one place to another -Tool use may have favored two-legged walking (weapons or carrying implements) -Long-distance travel may have been made more efficient

• Energy efficiency in walking

• Reduced heat stress during walking

advantages of bipedalism (in terms of striding bipedal gait and morphological changes presumed to be associated with endurance running or ER relative to other forms of locomotion used by other apes)

-thermoregulatory advantage: allows us to move about during hottest parts of the day -Femoral Bicondylar angle in assoc. w/knee joint-- closer to line of action of human center of gravity [COG] –helps in providing greater balance during human unipedal stance during bipedal walking

• due to humans having a striding bipedal gait, we have smoother movement flow

• biped chimps have a waddling gait, which causes bent hips and knees

• endurance running: stabilized foot arch, enlarged heelbone, balanced hear, low wide shoulders, short snout, narrow chest, large hip/knee/anide joints

what trace fossils used to verify bipedalism in the Au.? what are their dates?

Au. afarensis:

• 4-3.5 mya

how does thermoregulation change with respect to bipeds vs quadrapeds, and what aspects of thermoregulation facilitate bipedal running?

• in bipeds, thermoregulation allows us to move during the hottest parts of the day -small part of the body is actually exposed to the sun - running may be facilitated by the large butts (3 gluteal muscles used in running); short toes; long achilles tendon; long lower limbs, short forearms

• quadrapeds encounter more solar regulation and less wind than bipeds; does not allow them to move during the day's weather peak

the diversification of different hominin forms seen in the fossil record between 2-3 mya

- Au. africanus, 3-2 mya; discovered in South Africa 1924 by Raymond Dart; not initially accepted as human ancestor

what are the site locations of major hominin forms discussed in class?

- Lucy (Au. afarensis) - 1974, Hadar - footprints that most likely belong to them found in Laetoli in 1976 - Au. anamensis - 1960s-1990s, Lake Turkana, Kenya - Nutcracker Man (Zinjanthropus boisei or Paranthropus boisei) - 1959, Olduvai Gorge, Tanzania - Paranthropus robustus (Au. robustus) - 1930s-1950s in South Africa

what are the general cranio-dental features that help to distinguish the 'paranthropines' from the australopithecines?

paranthropines - small brain (400cc) - compound temporal nuchal crest - huge sagittal crest - broad, dished face - very large post canine teeth - masticatory muscles - eat tough/hard to process foods australopithecines - tiny anterior teeth and HUGE posterior teeth - large brow ridges - post-orbital constriction

what is the shape of the dental arcade of said forms and how are they distinguished from living chimps

paranthropines - very large post-canine teeth - molars are the size of a nickel australopithecines - thick dental enamel

what is the time frame for the emergence of the Homo genus?

3-2.5 mya

why are homo habilis and homo rudolfensis sometimes considered junk species?

both species have a lot of detached parts, which makes it hard to determine certain aspects of the construction

what is the time for the appearance of the Homo ergaster (African Homo erectus)?

1.8 mya in Africa

where in Africa are some of the earliest fossils of Homo found?

East African Rift Valley South Africa Chad Kenya Ethiopia

which fossil hominin appears to have been the first to have left Africa and lived in other portions of the Old World?

Homo ergaster

what are 3 South African limestone cave sites associated with early fossil hominids, including early Homo?

Taung Swartkrans Sterkfontein

what are the key cranial and post-cranial characteristics that help to distinguish early forms of Homo from the earlier species of Australopithecus

homo - From the neck down they all look the same - Small cranial capacity - Low forehead - Pronounced brow ridge (supraorbital torus) - large posterior teeth - not as large as Peranthupus - Thick cranial vault bones - Sagittal ridge - Cranial capacity - Broad base of skull australopithecus - knee joint

what are the implications of the WT-15000 fossilized skeleton and aspects of its skeletal characteristics that represent 'new' adaptive features?

-Large body size and brains size -Tropical body type -Tall and with narrow hips -Projecting external nose -Large number of anatomical regions that would have facilitated the ability to run - endurance running - compared to lucy -WT: large butts (3 gluteal muscles) - use gluteus maximus (ascending and descending, and running), long ligament from cranial vault to pelvis (acts as a shock absorber undergoes compression and releases), plantar arch also acts as a shock absorber during running, relatively short toes - foot stability (joint stability and joint mobility dif.) used in combination with other parts of our foot that allows a change of gears (diff. Running speeds), long achilles’ tendon (shock and energy), long lower limbs, short forearms - engage in running (efficiently move effortlessly) -When walking there is always one foot on the ground, but in running there is a no contact faze briefly - when hitting the ground the body is absorbing, but toeing off releases that energy -Comparison of anatomical traits in au. Afarensis to H erectus that may facilitate endurance walking and endurance running -Suggestion is to hunt animals for their meat

how may eat-eating have influenced gut size and brain evolution in early Homo members?

made guts smaller than expected and brains larger than expected

distinguish several of the key features/evidence used in the debate regarding whether early Homo relied primarily on scavenging, hunting, or both in the acquisition of meat as part of its diet

• cut marks not equivalent to hunting

  • Hominins too small and too poorly encephalized to hunt

  • Scavenging

  • Probably both

  • Questions concerning primary access to carcasses

what are the distinctions between scavenging fresh kills from the carnivore guild vs scavenging for carrion

how has taphonomy been used to distinguish primary access to carcasses vs secondary access, and how have taphonomic studies fueled the debate regarding scavenging vs hunting in earlier Homo

taphonomy: the study of what happens after death - discerns marks from teeth vs cut-marks from stone tools - what is eaten and what isn't - Elements that are left are parts of the body that are more dense and difficult to process - left with bones

what are the series of 'firsts' in terms of behavior and migration associated with H. erectus

• first appear in Africa 200-300 kya

• spread out of Africa to Europe and Asia and temperate zones

• created bifacial tools aka Acheulean Industry

what are the key H. erectus sites found in the Old World, including Dmanisi?

• Dmanisi - Homo ergaster (1.8 mya)

• East and South Africa - H. habilis

• East Turkana

  • KNM ER 140 (well-known H. habilis)

what is the evidence used to suggest social care in H. erectus?

• periapical abscess in the right mandibular incisor area

• enentulous (loss of teeth) someone had to feed them

box 11.1

what are the various stone tool forms associated with the Oldowan tool industry?

• Chopper–for bashing

• Flakes: used to cut up material (plant, prey, etc); knocked off cobblestone

• Hammer stone: used to bash an item and became smooth from its continuous use

• Discoids

• Polyhedrons

• Heavy duty core scraper

what are the hypotheses associated with the idea that handaxes were used to butcher animals?

• increased use of meat and use of bifaces

what were the ideas associated with the hypotheses that complex foraging has shaped hominin life histories?

• complex foraging shows evidence for extraction

  • requires intelligence and learning--larger brains, long juvenile period, increased longevity

extractive foraging vs. collecting food resources

extractive:

• termites and honey and tubers

• requires intelligence and learning

• reduced dimorphism

• large brain

• long juvenile period

• increased longevity' food resources:

• fruit and leaves

why is meat-eating suggested to favor food sharing

food sharing (tolerated theft) small prey usually isn't shared large prey shared with other members of group males share meat sources with the community

how are 'tolerated theft' and meal sharing closely related but still distinct?

tolerated theft:

• mothers with infants (if a child steals its mothers food, that is tolerated because the mother is caring for the infant) meal sharing:

• small prey usually isn't shared

• large prey shared with other members of group

• males share meat sources with the community

how does prey body size facilitate/discourage meat sharing in chimps?

small prey: usually not shared large prey: usually shared within the community

what is the evidence from Swartkrans for extractive foraging and the prey extracted in earlier hominins

termite extractive foraging

what are the distinctions between the posterior and anterior dentition w/ respect to paranthropines

very large post canine teeth nickel sized molars

-Be familiar with how morphological aspects of the dentition and the cranial morphological complexes associated with chewing provide information regarding primate diet and the quality of their foods.

-specialized vegetarian diet involving much chewing and grinding

• Small bodied primates consume higher quality, higher energy foods

• Larger bodied primates able to consume lower quality, lower energy foods

  • Bunodont - low rounded molar cusps

how does diet composition and patchy food distribution influence aspects of extractive foraging

Diet - tough foods or hard to process foods - Would have needed large muscle mass to chew - muscles of mastication - Sagittal crest seen in mammals with small brain case, large teeth and jaws, and powerful jaw muscles - Origin of temporalis muscles along midline of skull connecting to the crest

what is meant by Central Place Foraging and its impact on human food sharing

the probability of occurrence of an animal decreases with the distance to the central location

gracile vs. robust

• Balanced dentition of gracile forms suggests greater omnivory

• Tiny anterior and huge posterior teeth, sagittal crest, and large brow ridges of robust forms suggest a specialized vegetarian diet involving much chewing and grinding

-Know the characteristics of the Oldowan lithic industry.

Flakes, hammer stones, cores Chopper–for bashing Flakes: used to cut up material (plant, prey, etc); knocked off cobblestone Hammer stone: used to bash an item and became smooth from its continuous use Discoids Polyhedrons Heavy duty core scraper

-Know the primary characteristics of the Acheulean lithic industry inclusing the unique features of a handaxe.

Appears 1.75 mya Biface: hand ax, cleaver Hand axes have a teardrop shape More standardized than Oldowan tools Made by Homo erectus No real innovation in design for >1my Oldowan tools did not disappear Ancestors were still able to find some use of these tools Uses for the hand ax Butchering larger animals Dispensing flake tools Woodworking Acheulean Industry remained unchanged for nearly 1 million years

-Know the basic cranial features associated with Homo erectus.

From the neck down they all look the same Small cranial capacity Low forehead Pronounced brow ridge (supraorbital torus) large posterior teeth - not as large as Peranthupus Thick cranial vault bones Sagittal ridge Cranial capacity Broad base of skull Very little variation associated w postcranial skeleton of homo erectus from skull down Projecting external nose Suggestion that later forms of H. erectus exhibit large differences that can be attributed to regional variation East African H. erectus have thinner cranial vault bones East Asian H. erectus has a more projected external nose