Anthro 209 Exam Material
Be familiar with the issues involved in deciding whether a given set of fossils represents one
species or more than one species, and be able to give an example of such a debate in the hominid
Differences between fossils can be due to either different species or simply high variations
within the species. These variations can include sexual dimorphism; in many cases, this can result in
characteristically more robust craniums and bodies, as well as slight changes in dentition.
We are unable to determine whether or not two individuals were able to mate with each other.
According to the biological species concept, this would make them one species. The scarcity of fossils
as well an degradation of DNA means its not currently possible to determine relatedness of fossils.
Because of this, anthropologists use physical features to see if two individuals show
considerable differences between each other. The division of species becomes arbitrary. Even
anthropologists acknowledge this through classifications of others as “splitters” or “lumpers”.
One example of this debate is within the Homo genus. Homo habilis and Homo rudolfensis have
been largely debated as to whether they are two species or just one. Homo habilis differs from Homo
rudolfensis by having a less robust face, a slightly smaller body and brain size, as well as more robust
teeth. However, both share the loss of anterior pillars, the overall increase in brain expansion, and the
further reduction of the canines.
It has been suggested that, particularly for H. rudolfensis, these traits are indicative of a late,
unusual Australopithecine. Not only do we have difficulty determining the specie-relatedness, but the
age of the fossils allows for debates regarding genus of the fossils.
Further, because these fossils are from the Homo genus officially, anthropologists are interested
in the possible use of stone tools. If H. habilis and H rudolfensis are indeed two different species, then
they likely have different adaptations and culture that accompany this tool use.
Be able to name the key defining traits and dates of the fossil hominid species we have discussed,
and the type of material culture (if any) associated with them. Pay special attention to the trends
of increasing brain size and increasing cultural capacity.
The fossil hominid species that we have discussed so far include, in order of appearance:
1. Sahelanthropus tchadensis – surprisingly flat face, thicker molar enamel, anterior
2. Orrorin tugensis – elbow and hands suggest climbing, large canine with sectorial
3. Ardipithecus kadabba – large canine, sectorial premolar, toe phalanx may suggest
4. Ardipithecus ramidus – small brain, less prognathism, no sectorial premolar, and smaller
canine. Postcranial shows bidpedal traits: os coxae have some adaptations, long arms,
stiffer foot, and dorsiflextion wrists.
5. Kenyanthropus platyops – first accepted hominid – flatter face and small ape-like molars.
6. Australopithecus anamensis and afarensis – early Australopithecines (also includes K.
platyops). They show a decrease in canine size, presence of diastema, U-shaped dental
aracade, and smaller premolars and molars than later hominids. Postcranial features
include broad, short, flared iliac blades, anterior foramen magnum, femur with carrying
angle, partial arch in feet, and short legs, strong wrists, and curved phalanges (which
suggest climbing). 7. Australopithecus africanus and Australopithecus sediba – gracile forms of
Australopithecines. They, along with robust Australopithecines (see below) have the
following traits: full incisiform canine, no canine diastema, parabolic dental arcade, and
megadontia. They also have anterior pillars, zygomatic prominence, and a small brain.
8. Australopithecus boisei, Australopithecus robustus, and Australopithecus aethiopicus –
are robust Australopithecines. They have the above traits, but also have cresting on the
skull, wide zygomatics, and higher postorbital constriction. These three features may
indicate a greater degree of chewing. Further, robust Australopithecines have large
supraorbital tori and anterior pillars.
9. Homo habilis – has a much larger brain. This is the first fossil where we see extensive
brain expansion. Other traits include less megadontia, narrower zygomatics, no anterior
pillars, and high variability between size of males and females. H. habilis has an Oldowan
10. Homo rudolfensis – possibly belongs in the same species as Homo habilis. A larger brain
and body size, as well as more robust face and teeth characterize it. See first question.
11. Homo erectus – diverse group of hominid fossils first identified 1.8 mya. Key traits of H.
erectus include: thick vault bones, heavy supraorbital torus with pentagonal silhouette,
modern limb proportions, another increase in brain size, and an Acheulean tool tradition.
12. Homo ergaster – similar to H. erectus, except is has a more lightly built cranium. Ergaster
can be viewed as the African equivalent to H. erectus.
13. Dmanisi material and Flores hominids – both indicate the high variability that existed
within H. erectus. Dmanisi material was found outside of Africa immediately after we see
the evolution of H. erectus 1.8 mya. The Flores hominids were much later, approximately
38 kya, and were very small, bipedal hominids.
14. Homo heidelbergensis – key traits of these archaic Homo sapiens include a larger brain, a
more globular brain case, heavy supraorbital torus, and a low forehead. The Acheulean
tool tradition continues.
15. The Neandertals – have a larger brain than modern Homo sapiens, as well as an occipital
bun, a low forehead, double-arched brow ridges, and midfacial prognathism. They have a
wider torso, shorter limbs, and are generally more robust. Strong use of tools, possibly in
hunting and fire (we know they definitely used fire though).
16. Modern Homo sapiens – there is no increase in brain size. There is, however, a decrease in
facial prognathism, a canine fossa, smaller jaws and teeth, and the appearance of a chin.
Early modern humans do not suddenly show all the modern traits; this happens gradually.
Extensive tool use.
Be familiar with the anatomical changes that adapt the human skeleton to bipedalism, know
when these changes arose in the fossil record, and be able to describe the differences between
the postcranium of Australopithecus afarensis and ours that suggest it still did significant
Bipedalism is the habitual movement on two legs. Modern Homo sapiens are highly adapted for
The pelvis is broad and squat compared to apes. The iliac blades are flared; this allows internal
organs to rest comfortably in an upright position. The gluteal minimus and medius stabilize the
pelvis during walking. However, changes due to bipedalism cause the diameter of the pelvic
outlet to decrease. The female pelvis is widened; the pubis angle increases and the wings of the
sacrum are widened. The legs are longer in proportion to the rest of the body. A carrying angle on the femur allows
the center of gravity to remain above the foot. Further, all joints are less flexible. This allows for
less muscular effort when standing and walking.
The feet are used for walking only. There is a strong rigid arch with a non-divergent big toe.
The arms of humans are shorter and phalanges are not curved.
The foramen magnum is moved forward. This allows the skull to balance easy and there is less
muscular effort for the neck.
The spine shows larger lumbar vertebrae to support more weight, and the S-shape balances the
torso over the hips.
Bipedal traits vary between Australopithecines and modern Homo sapiens. The os coxa in
Australopithecines shows broad, flared iliac blades, similar to humans. The foramen magnum is
shifted forward, the spine shows a lumbar curve, the femur has a carrying angle, and the foot has an
arch and no opposable toe.
However, Australopithecines have some ape-like forms. The legs are shorter relative to the arms.
The wrists are much stronger than humans, and the phalanges of both the toes and fingers are longer
and curved. These three traits suggest that afarensis still did significant climbing. Laetoli footprints
and analysis of stride length suggest that bipedalism was less efficient. Climbing perhaps provided
protection against predators.
Be familiar with the basic arguments about the origin of language and tools, and the ways in
which modern non-human primates have been used as models when studying these problems.
Language is based on a set of arbitrary symbols. Use of grammar allows an infinite combination
of words. Human language is an open system. Language in innate in humans; we have Wernicke’s
area and Broca’s area which are adapted for language.
In order to explore when and how language developed, we use evidence from modern animals,
fossil hominid anatomy, and archaeology (material culture).
Modern Animals – calls of animals have some similarities to language. Vervet monkeys, for
example, have calls that are classified as closed systems.
Extensive research has been done on apes with regards to language. Chimps were unable to
speak, because of the anatomy of their vocal tract. But, apes were shown to have good
comprehension ability. Captive apes show spontaneous learning, invention of new terms, and
consistent use of symbols. Further, they are able to teach other apes. Sherman and Austin tested
based on categories and found that apes are able to understand that symbols represent objects.
The implication for human evolution is that our ancestors had a similar capacity. Simple logic