Deck 10: The Earliest Hominins

Question 1

Fossil candidates for the "first" hominins include

A) Pan, Pongo, and Hylobates.
B) Sahelanthropus, Orrorin, and Ardipithecus.
C) Paranthropus, Homo erectus, and Homo ergaster.
D) Homo heidelbergensis, Neanderthals, and Homo sapiens.

Answer 1

B

Question 2

Based on fossil evidence, what is the relationship between the evolution of bipedalism and large brains in hominin evolution?

A) Bipedalism preceded large brains by millions of years.
B) Large brains preceded bipedalism by millions of years.
C) They co-evolved.
D) The first hominins had large brains and were quadrupedal, while later hominins had small brains and were bipedal.

Answer 2

A

Question 3

Which of the following statements correctly describes the distribution of cortical bone in the femur?

A) It is diagnostic of locomotor patterns.
B) It can be used to estimate body weight.
C) It cannot be measured in fossils.
D) It tells you how strong a species was.

Answer 3

A

Question 4

Between 4 and 2 Ma we see some of the distinctive features that differentiate hominins from apes. These features include

A) evidence of bipedal locomotion.
B) small posterior teeth (molars and premolars).
C) large canines.
D) the loss of a tail.

Question 5

Genetic data indicate that the last common ancestor of humans and chimpanzees lived about

A) 2 Ma.
B) 5 Ma.
C) 12 Ma.
D) 8 Ma.

Question 6

The cortical bone on the femur of ________ has a humanlike pattern of thickness.

A) Sahelanthropus tchadensis
B) Ardipithecus kadabba
C) Orrorin tugenensis
D) none of the these

Question 7

Compared with great apes, Ardipithecus ramidus was characterized by ________ molar enamel and ________ canines.

A) thicker; larger
B) thicker; smaller
C) thinner; larger
D) thinner; smaller

Question 8

Senut and colleagues argue that Orrorin tugenensis is likely a hominin on the basis of what evidence?

A) features of the base of the skull
B) footprints preserved in volcanic ash
C) features of the femur
D) features of the spine and ribs

Question 9

Bipedalism may have evolved because it allowed hominins to

A) keep cool in savanna environments.
B) plant and cultivate food.
C) travel easily in the trees.
D) swim as well as travel on land.

Question 10

During the late Miocene, which of the following occurred in Africa?

A) It became warmer and wetter.
B) It had an expansion of dense forests.
C) It experienced less rain and was more seasonal.
D) It shifted farther north.

Question 11

Ardipithecus ramidus is apelike in that it had

A) small molars.
B) thick enamel.
C) a forwardly placed foramen magnum.
D) a femur that angles inward.

Question 12

Derived human traits that distinguish modern humans from apes include

A) facultative bipedalism.
B) a short juvenile period.
C) a large brain-to-body-size ratio.
D) less body hair.

Question 13

The oldest hominin is

A) Australopithecus.
B) Sahelanthropus.
C) Zinjanthropus.
D) Pithecanthropus.

Question 14

Humans have

A) a femur that descends vertically from the pelvis.
B) a knee joint that is not slanted or angled toward the midline of the body.
C) cortical bone that is evenly distributed around the femur.
D) a divergent big toe.

Question 15

Which of the following statements is true of Orrorin tugenensis?

A) It was quadrupedal.
B) It was ancestral to Sahelanthropus tchadensis.
C) It is dated to 4 million years ago.
D) It lived in a mix of woodland and savanna.

Question 16

Surprising findings regarding Ardipithecus ramidus include

A) limb proportions like those of modern great apes.
B) specialization for below-branch feeding.
C) limb proportions like those of monkeys.
D) hands that are similar to those of African apes.

Question 17

Compared with the dentition of chimpanzees, Sahelanthropus tchadensis had

A) larger canines.
B) upper canines that are not sharpened against the lower premolar.
C) thinner enamel.
D) larger incisors.

Question 18

The transition from hominoid to hominin occurred during a transition from

A) forest to savanna.
B) savanna to forest.
C) cold to warm climates.
D) a single continent (Pangaea) to multiple continents.

Question 19

Among the pre-4-Ma fossils from Ethiopia that some paleoanthropologists include in the hominin family, ________ has a canine that sharpens itself against the first premolar.

A) Sahelanthropus tchadensis
B) Ardipithecus kadabba
C) Orrorin tugenensis
D) Ardipithecus ramidus

Question 20

The very first hominins date to about ________ years ago.

A) 60 million
B) 6 million
C) 600,000
D) 60,000

Question 21

Which of the following is a feature associated with bipedal locomotion?

A) femurs parallel with the midline of the body
B) arched feet
C) a narrow and long pelvis
D) a foramen magnum positioned more posteriorly (toward the back of the skull)

Question 22

Australopithecus africanus shares which of the following traits with humans?

A) more air pockets in the skull
B) canines that are less dimorphic
C) more prognathism
D) similar height

Question 23

Which of the following bones can provide evidence that a fossil animal was bipedal?

A) humerus, fingers
B) a hand with an opposable thumb
C) ear bones (related to balance)
D) pelvis, femur, skull

Question 24

The first lower premolar of chimpanzees has ________, the first lower premolar of humans has ________, and Australopithecus afarensis had ________.

A) two equal cusps; no cusps; a small and a large cusp
B) one cusp; no cusps; two equal cusps
C) one cusp; two cusps; no cusp
D) one cusp; two cusps; a small and a large cusp

Question 25

Relative to hominoids in general, hominins tend to have

A) thin enamel.
B) thick enamel.
C) a parallel dental arcade.
D) three premolars.

Question 26

Australopithecines were

A) prehominin apes from the Miocene from which hominins evolved.
B) toothless wonders from the late Cretaceous.
C) bipedal primates.
D) primates with brains larger than hominoids.

Question 27

The fossil specimen known as "Lucy"

A) is a 3.2-million-year-old australopithecine.
B) is a complete skeleton.
C) was not bipedal.
D) was named after the Peanuts character.

Question 28

The Laetoli footprints show that Australopithecus afarensis was

A) an efficient biped compared with humans.
B) an inefficient biped compared with humans.
C) about as equally efficient a biped as humans.
D) not bipedal.

Question 29

Australopithecus garhi had

A) large molars, similar to those found in Paranthopu.
B) small molars similar to modern humans.
C) chimpanzee-like teeth.
D) no diagnostic cranial bones but several postcranial bones.

Question 30

Which of the following skeletal features indicate(s) arboreal adaptations?

A) long lower limbs
B) eyes moved toward the side of the head
C) curved fingers and toes
D) reliance on the sense of smell

Question 31

Australopithecus afarensis was

A) sexually dimorphic.
B) a stone-tool manufacturer.
C) monogamous.
D) older than Ardipithecus ramidus.

Question 32

Australopithecus africanus is most similar to which of the following species?

A) Australopithecus afarensis
B) Australopithecus boisei
C) Ardipithecus ramidus
D) Sahelanthropus tchadensis

Question 33

It is likely that Australopithecus afarensis

A) matured rapidly, like chimpanzees.
B) had a brain size three to four times bigger than those of chimpanzees.
C) made and used stone tools to scavenge meat.
D) lived throughout West, Central, East, and South Africa.

Question 34

Bipedalism may have evolved because it allowed hominins to

A) keep warm.
B) sit upright.
C) harvest food from small trees.
D) run.

Question 35

Au. Afarensis has a sciatic notch similar to that of

A) chimpanzees.
B) humans.
C) Old World monkeys.
D) gorillas.

Question 36

Australopithecus anamensis and ________ may be part of a single lineage spread over a long period of time.

A) Australopithecus afarensis
B) Paranthropus aethiopicus
C) Australopithecus africanus
D) Homo rudolphensis

Question 37

A femur from a bipedal primate ________ than that of a quadrupedal primate.

A) has more torque
B) is shorter
C) is angled inward more
D) is angled outward more

Question 38

Bipedalism may have evolved from hominin ancestors that were

A) above-branch quadrupeds.
B) below-branch, suspensory primates.
C) vertical clingers and leapers.
D) amphibians.

Question 39

Features showing that Australopithecus afarensis is a hominin include

A) a large brain.
B) the lack of a tail.
C) bipedalism.
D) thin molar enamel.

Question 40

Derived features of Australopithecus afarensis include

A) bipedalism.
B) a large brain.
C) a tail.
D) prognathism.

Question 41

Which known member of the genus Australopithecus is most like an ancestor to later australopiths and even of our genus, Homo? Support your suggestion with information about features of the hominins noted in the chapter.

Question 42

What can be said about the phylogeny of the early hominins?

A) The absence of an agreed upon phylogeny of hominins makes it impossible to understand early hominin evolution.
B) Only recently have we developed a secure and agreed upon phylogeny of early hominins.
C) We do not have a secure, agreed upon phylogeny for early hominins, but we can still understand the general patterns of early hominin evolution.
D) The most obvious pattern indicated by early hominin evolution is the early increase in brain size and slowing down of maturation rates.

Question 43

Isotope analysis of Australopithecus teeth suggests that these hominins ate

A) C₃ plants, probably including forest fruits and leaves.
B) primarily C₄ plants, suggesting that most Australopithecus lived in open grassland.
C) mostly C₃ plants early on, shifting to mostly C₄ plants over time.
D) an even mixture of C₃ and C₄ plants, suggesting no change in diet for millions of years.

Question 44

________ is a hominin with a wide, flat face and small teeth with thick enamel, dating to 3.5-3.2 Ma.

A) Orrorin tugenensis
B) Ardipithecus ramidus
C) Australopithecus afarensis
D) Kenyanthropus platyops

Question 45

Which of the following statements is true of Paranthropus aethiopicus?

A) It is the most robust of the robust australopithecines.
B) It retains many primitive characteristics of Australopithecus afarensis.
C) It shares many derived characters with the genus Homo.
D) It is the direct ancestor of genus Homo.

Question 46

Which genus of early hominins had huge molars for extremely heavy chewing?

A) Paranthropus
B) Australopithecus
C) Kenyanthropus
D) Homo

Question 47

What was the diet of the robust australopiths? What are the anatomical features associated with their diet?

Question 48

Imagine you have found a skull with an ape-size brain, sagittal crest, very large back teeth, and large cheekbones. Based on this information, this is most likely a specimen of

A) Australopithecus afarensis.
B) a robust australopith.
C) Australopithecus africanus.
D) a modern human.

Question 49

Which of the following statements is true of Paranthropus robustus?

A) It was about 1.3 meters tall and bipedal.
B) It was not fully bipedal.
C) It had very small molars.
D) It had very large incisors.

Question 50

Australopithecus africanus's maturation rate was estimated by

A) the cranial suture closure.
B) the long bone suture closure.
C) relative tooth eruption.
D) relative nail growth.

Question 51

Evidence that the robust australopithecines ate hard foods includes

A) the browridge.
B) the nuchal crest.
C) flared zygomatics.
D) a small brain.

Question 52

Compare and contrast the characteristics of Sahelanthropus, Orrorin, and Ardipithecus. In what kinds of environments did they live? How did the environment shape the evolution of their morphology?

Question 53

Paranthropus robustus had skull structures specialized for

A) cannibalism.
B) heavy chewing.
C) carnivory.
D) speech.

Question 54

Studies of tooth enamel tell us that

A) C₄ plants are woody plants while C₃ plants are grasses and sedges.
B) Australopithecus africanus and Paranthropus robustus shared a variable diet that may have included animals that fed on C₄ plants.
C) chimpanzees feed mainly on C₄ plants.
D) Paranthropus boisei ate mostly C₃ plants.

Question 55

Discuss three hypotheses concerning the evolution of bipedalism.

Question 56

What is the anatomical evidence that early australopithecines were bipedal?

Question 57

Raymond Dart argued that the Taung child was bipedal because it

A) had a femur angled toward the midline of the body.
B) had an S-shaped spinal column.
C) was found near footprints like those at Laetoli.
D) had a downward facing foramen magnum.

Question 58

Compared to the gracile australopiths, the robust australopiths

A) were twice the body size.
B) exhibit a number of derived features of the cranium and teeth.
C) were not appreciably different in any way.
D) have all come from East African sites.

Question 59

The evidence is compelling for either Sahelanthropus or Orrorin to have been most like the first hominin. Pick one, and make your case for why you think so.

Question 60

Australopithecus africanus has derived features not shared with humans. These include

A) a fully bipedal gait.
B) large canines.
C) heavy chewing adaptations.
D) a modified pelvis.

Question 61

Why might there be uncertainties about the relationship of different hominins to each other?