Physical Anthropology Midterm 2 Flashcard Set 3

Front 1

Laetoli footprints

Back 1

Footprints in hardened ash discovered by Mary Leakey at Laetoli (in Tanzania) dating 3.7 mya. Provide evidence for bipedality: similar to footprints produced by modern humans (but smaller and closer together)
Shows all hallmarks of human bipedalism: Toes all in one line, no opposable big toe. Clear pattern of arches like modern human feet– longitudinal and medial. Evidence of heel strike, rolling transfer of weight along lateral portion of foot.

Front 2

facial prognathism

Back 2

the degree to which the face projects in front of the brain case

Front 3

sagittal crest

Back 3

a ridge along the top of the skull that serves as the attachment point for the temporalis (chewing) muscle. associated with large mastication muscles. present in robust but not gracile australopithecenes.

Front 4

diastema

Back 4

a gap between the canine tooth and an adjacent tooth. when an ape closes its mouth, the upper canines fit into the lower diastema and vice versa. part of honing complex. **a characteristic that distinguishes apes from hominids, which don't have diastema.**

Front 5

zygomatic arch

Back 5

the cheekbone. mastication muscle inserts there, so size of zygomatics can indicate size of chewing complex.

Front 6

cranial capacity

Back 6

a measure of brain volume. the reduction in size of the masticatory muscles leads to greater cranial capacity.

Front 7

foramen magnum

Back 7

the large opening in the skull’s occipital bone, where spinal cord is attached. it is located at the bottom of the skull in bipeds, and farther up in non-bipedal species.

Front 8

bicuspid premolars

Back 8

a dental characteristic that is found in higher primates/anthropoids (including humans). bicuspid premolars have two cusps, i.e. the top of the tooth is sort of cup-shaped with one point on each side.

Front 9

parsimony

Back 9

the theory that the simplest explanation is the most likely one. parsimony is a guiding principle in drawing evolutionary trees: it says that the best hypothesis is the one requiring the fewest evolutionary changes.

Front 10

skeletal evidence for bipedalism

Back 10

-low foramen magnum
-lack of opposable big toe
-a short pelvis with blades that are oriented side-to-side (pelvises of non-bipeds are long and blades are oriented back-to-front)
-long legs and short arms
-shorter, straighter fingers and toes
-no opposable big toe
-foot has double arch

Front 11

theories for bipedalism adaptation

Back 11

-Patchy Forest Hypothesis: as forests became more fragmented toward end of Miocene, bipedalism was more efficient for locomotion over areas with few trees, and freed hands to carry food
-Provisioning Hypothesis: males whose hands were free to carry food were able to be better providers for their mates and young; this relieved some of the burden of provisioning from the mothers, who were then able to take care of more than one child at once. mothers were not receptive to mating when burden of childcare was great; this increased receptivity to mating and reduced time between births, leading to more offspring.

Front 12

Homo habilis

Back 12

-earliest Homo species, probable descendant of Australopithecus gahri and ancestor of Homo erectus
-compared to austs., has larger brain and smaller chewing complex
-fossils from 1.7 to 1.8mya
-found in Olduvai, East Turkana, and elsewhere in East and South Africa: same geographical distribution as austs.
-made and used stone tools (Oldowan tools)
-considered to represent transition from australopithecines to Homo
-name means 'handy person'
-brain size 580-650ml, larger than australopithecines but smaller than other species of early Homo
-has less broad molar and premolar cheek teeth than australopithecines

Front 13

hominid

Back 13

defined by two obligate behaviors: bipedal locomotion and nonhoning chewing.

Front 14

Homo rudolfensis

Back 14

-1.8 to 1.9 mya
-found around Lake Turkana
-slightly smaller than H. habilis specimens
-considered by some to be part of H. habilis species, not its own species.

Front 15

Homo ergaster

Back 15

Some believe that Homo erectus is a term to be used only for the fossils from Asia, and that the earliest species in Africa ought to be called by another name, Homo ergaster.
Scientists in favor of separating erectus from ergaster are doing this to position african species as ancestor of homo to exclusion of asian species: out of africa model. Not a lot of morphological support for this species designation.

Front 16

Homo erectus

Back 16

-1.8 to 3 mya, contemporary with other Homo species
-found in East Turkana
-large brains (1200-1500ml), bigger body, smaller back chewing teeth
-larger than earlier hominids
-longer legs, shorter arms
-pronounced sexual dimorphism
-considered most likely of early Homo species to be human ancestor
-earliest Homo species to be found outside Africa

Front 17

Zhoukoudian

Back 17

-archaelogical site in a cave in northern China
-northernmost site of early Homo fossils, cold climate: possible evidence of use of clothing.
-bones of 40-50 Homo erectus individuals, 400,000 to 800,000 years old
-animal and plant remains. animal bones have cut marks
-all fossils from site lost in transit
-two different interpretations of data:
*1 (discussed in book): evidence of controlled fire; cut marks in bones are evidence of tools.
*2 (more recent, discussed in ppt) fire probably not controlled; cuts in animal bones probably from hyena teeth. cave probably a hyena den, bones are of their victims.

Front 18

Dmanisi

Back 18

-site of hominid fossils in Republic of Georgia.
-fossils dated 1.5 to 1.8 mya

Front 19

Ubeidiya

Back 19

-site on the Jordan River in Israel, on a natural corridor out of Africa.
-No hominid fossils, but stone tools similar to those from East Africa (Oldowan), and many African mammal bones.
- Dated to about 1.5-1.6 myr.

Front 20

Perning

Back 20

Earliest of a series of sites on the island of Java (Indonesia). A child’s skull is dated to 1.6-1.8 mya