Deck 8: Early Hominins

Question 1

Australopithecus had at least seven species,

A) Au. anamensis, Au. afarensis, Au. kenyanthropus, Au. kadabba, Au. garhi, Au. robustus, and Au. sediba.
B) Au. anamensis, Au. afarensis, Au. africanus, Au. garhi, Au. robustus, Au. boisei, and Au. sediba.
C) all discovered and named by the Leakey family.
D) all discovered in Africa except Au. boisei.
E) but only five of them have been confirmed to be bipedal, thus putting into question that all australopithecines were hominins.

Answer 1

Au. anamensis, Au. afarensis, Au. africanus, Au. garhi, Au. robustus, Au. boisei, and Au. sediba.

Question 2

Interestingly,some of the physical markers that have led scientists to identify certain fossils as early hominins rather than apes are features that have been lost during subsequent human evolution.Which of the following is an example of this?

A) stereoscopic vision
B) climbing ability
C) thin enamel on teeth
D) big back teeth
E) chimplike tool use, such as termite capture

Answer 2

big back teeth

Question 3

A 2001 fossil find called Orrorin tugenensis,dated 6 million years of age,

A) appears to have been a chimp-sized creature that climbed easily and walked on two legs when on the ground.
B) lacks any possible evidence that it was bipedal.
C) is the undisputed "missing link."
D) was found in South America, suggesting that the transition into bipedalism may have happened there.
E) is older than the famous Toumai find.

Answer 3

appears to have been a chimp-sized creature that climbed easily and walked on two legs when on the ground.

Question 4

Which of the following statements about australopithecines is true?

A) Australopithecines had a higher incidence of rickets than genus Homo.
B) Australopithecines had smaller molars than genus Homo.
C) Australopithecines probably relied more on the use of tools than did the early Homo.
D) Australopithecus was the most geographically widespread of all hominin genera.
E) Australopithecines as a group inhabited the earth longer than any other hominin genus.

Question 5

In 2009,a newly reported Ardipithecus find-a fairly complete skeleton of A.ramidus-dubbed Ardi (4.4 m.y.a.)

A)replaces Lucy (3.2 m.y.a.)as the earliest known hominin skeleton.
B)lived in a dry savanna habitat.
C)stood about a foot shorter and weighed half as much as Lucy.
D)is the new undisputed oldest hominin fossil.
E)is the ancestor of Homo but not australopithecines.

Question 6

Bipedalism,considered a key defining characteristic that differentiated early hominins from other apes,

A) may have evolved as a result of anatomical changes caused by stone tool manufacturing.
B) evolved as a result of anatomical changes caused by an increase in brain size.
C) perhaps developed in the woodlands but became even more adaptive in a savanna habitat.
D) resulted in greater exposure to heat stress because on two feet, hominins spent increasingly more time in the open grasslands.
E) was accompanied by a sharp increase in hominins' climbing abilities.

Question 7

What is the most important difference between Australopithecus afarensis and the modern apes?

A) Au. afarensis had increased cranial capacity.
B) Au. afarensis had better color vision than apes.
C) Au. afarensis had a narrow chest, whereas living apes have a barrel chest.
D) Au. afarensis had lost its prehensile tail.
E) Au. afarensis was bipedal.

Question 8

Fossils of Australopithecus afarensis are particularly significant because

A) they show that humans evolved in Asia rather than Africa.
B) they are the oldest hominin fossils yet found in the New World.
C) Au. afarensis remains are the oldest to be found in association with evidence of both stone tools and fire use.
D) they comprise the first fossil evidence to confirm that bipedalism preceded the evolution of a humanlike brain.
E) they show that the gracile australopithecines were not hominins after all.

Question 9

Sahelanthropus tchadensis,or Toumai,

A) may be the oldest possible "missing link" between gorillas and Orrorin tugenensis.
B) moves scientists close to the time when humans and apes in the Americas diverged from a common ancestor.
C) looks more like a chimp than a human, specifically because of the placement of its foramen magnum at the base of its skull, which is farther back than in later hominins.
D) may be the oldest possible human ancestor yet found.
E) apparently lived in a habitat with scarce animal life and mountain terrain.

Question 10

All of the following about Ardipithecus kadabba are true EXCEPT that

A) it is recognized as the earliest known hominin, with the Toumai find from Chad, dated to 7-6 m.y.a., and Orrorin tugenensis from Kenya, dated to 6 m.y.a., as possibly even older hominins.
B) the kadabba find consists of 11 specimens, including a jaw bone with teeth, hand and foot bones, fragments of arm bones, and a piece of collarbone.
C) its bipedalism is still questioned because none of the fossil bones found was a pelvis or a femur.
D) it lived during the late Miocene, between 5.8 and 5.5 million years ago.
E) its fossils belong to individuals that were apelike in size, anatomy, and habitat.

Question 11

As this chapter makes clear,there are many issues within hominin evolution that remain open to debate.One of them regards the Kenyanthropus fossil found by Maeve Leakey,who argues that at least two hominin lineages existed as far back as 3.5 million years (the other being Au.afarensis).Taxonomic "splitters" tend to agree with her interpretation,while taxonomic "lumpers" disagree.These two interpretations highlight

A) the distinction between those who stress diversity and divergence, and those who focus on similarities across fossil finds.
B) that more fossil evidence isn't necessarily better, because it only leads to more misinterpretation.
C) the distinction between creationists and evolutionists.
D) the difference between those who consider bipedalism as the key hominin feature, and those that consider large brain size the key feature.
E) that not all paleoanthropologists value human diversity.

Question 12

What was the major hominin group that lived from about 4 to 1 m.y.a.?

A) Homo sapiens
B) Homo erectus
C) Ramapithecus
D) Australopithecus
E) Dryopithecus

Question 13

What is the significance of Kenyanthropus,a 3.5-million-year-old fossil that Maeve Leakey discovered in Kenya in 1999?

A) It puts an end to the debate between taxonomic "splitters" and "lumpers."
B) It confirms that the development of big brains preceded the onset of bipedalism.
C) It replaces Lucy (3.2 m.y.a.) as the earliest known hominin skeleton.
D) It is the ancestor of Homo but not australopithecines.
E) It suggests the possibility that at least two hominin lineages existed as far back as 3.5 million years ago.

Question 14

Although the first hominins appeared late in the Miocene,most hominin fossils have been dated to

A) 20 to 15 m.y.a.
B) the Holocene.
C) the Pliocene and Pleistocene epochs.
D) the early Miocene.
E) 400,000 to 300,000 years ago.

Question 15

Although we now know that the various species of Australopithecus discussed in this chapter do not form a distinct subfamily within the order Primates,

A) there are still some creationists who argue that they should form a distinct subfamily.
B) the designation australopithecine has stuck in describing them.
C) we still use the term australopithecine to honor the legacy of the Leakey family.
D) australopithecines certainly do form a distinct tribe.
E) some prominent paleoanthropologists are not convinced and have threatened to withdraw from the American Anthropological Association.

Question 16

All of the following are true about the recent discovery of the world's oldest child,dubbed "Lucy's baby," EXCEPT that

A) she is a member of Australopithecus afarensis, a species many anthropologists consider ancestral to humans.
B) the 3.3-million-year-old fossilized toddler was uncovered in northern Ethiopia.
C) her remains, which are amazingly complete, include a remarkably well-preserved skull, milk teeth, tiny fingers, a torso, a foot, and a kneecap.
D) the fossil suggests that the child died because her brain, which appears to have been larger than an average chimp brain at that age, was too large for her slowly developing skull.
E) the fossil supports the theory that Au. afarensis walked upright on two legs but still retained an apelike upper body, including two complete shoulder blades similar to a gorilla's, so it could have been better at climbing than are humans.

Question 17

Which of the following is NOT a location where australopithecine fossils have been found?

A) Ethiopia
B) Tanzania
C) Kenya
D) Gibraltar
E) South Africa

Question 18

Which of the following was a key obstacle that hominins' increase in brain size had to overcome?

A) larger skulls demanding more elastic birth canals, even though the requirements of skeletal development during a woman's lifetime limit the elasticity of birth canals
B) the challenges of walking with a head that is too heavy
C) overcoming the trend of clumsy locomotion that makes hominins vulnerable to predators
D) overcoming the trend of ever more self-sufficient children eager to separate themselves from their mothers
E) larger skulls demanding larger birth canals, even though the requirements of upright bipedalism impose limits on the expansion of the human pelvic opening

Question 19

"Lucy's baby," an important Australopithecus afarensis fossil from northern Ethiopia,includes a complete skull,mandible,and face.What is an important outcome of this find?

A) It indicates that Au. afarensis had a prolonged childhood period of slow brain growth.
B) It has a human-like skull and upper body, unlike Lucy.
C) It is the first fossil hominid child found alongside its mother.
D) It was found to have a large cranial capacity but was not bipedal, drawing into question how these traits develop in childhood.
E) It sheds light on growth processes in human ancestors, including brain and dental development.

Question 20

Northern Tanzania and the Afar region of Ethiopia have yielded some of the most famous and informative glimpses into hominin evolution.All of the following are true about fossil finds in these areas EXCEPT that

A) the Laetoli site in northern Tanzania yielded a series of fossilized footprints.
B) although the fossils from these two regions were deposited half a million years apart, their many resemblances justify including them all as part of the same species, Homo habilis.
C) Lucy, a tiny hominin female who lived around 3 m.y.a., was found in the Hadar site in the Afar region of Ethiopia.
D) the fossils from both Laetoli and Hadar forced a reinterpretation of the early hominin record, suggesting that hominins are much closer to apes than previously known.
E) the fossils from both Laetoli and Hadar are representative of Au. afarensis.

Question 21

Orrorin tugenensis and the Toumai specimen are unquestionably hominins.

Question 22

A characteristic trend in hominin evolution has been an increase in brain size,especially with the advent of the genus Homo.

Question 23

Postcranial material from Ardipithecus,the earliest widely accepted hominin genus (5.8-4.4 m.y.a.),indicates a capacity-albeit an imperfect one-for upright bipedal locomotion.

Question 24

Bipedalism has traditionally been viewed as an adaptation to open grassland or savanna country,although Ardipithecus lived in a humid woodland habitat.Perhaps bipedalism developed in the woodlands but became even more adaptive in a savanna habitat.

Question 25

The discovery of Sahelanthropus tchadensis (Toumai)indicates that early hominid evolution was not confined to East Africa's Rift Valley.

Question 26

Of the following features belonging to Australopithecus afarensis,which is evidence of its adaptation to bipedal locomotion?

A) the position of its foramen magnum underneath the skull
B) the development of an opposable thumb
C) the presence of crude stone tools
D) its cranial capacity
E) its relatively large grinding surfaces on the back teeth, compared to earlier primate fossils

Question 27

Oldowan pebble tools

A) were found at the same site and stratigraphic layer as the Ardipithecus kadabba fossils, dramatically pushing back in time the onset of stone tool use to the late Miocene.
B) contain evidence that they were used on fellow hominins, providing the earliest evidence of human warfare and cannibalism.
C) include elaborate axes and spears.
D) were also used to decorate burial sites, suggesting very early symbolic thought.
E) represent the oldest formally recognized stone tools.

Question 28

Which of the following statements about australopithecines is true?

A) They had a greater cranial capacity than Homo erectus.
B) They lived in the tropical forest.
C) They have been found predominantly in West Africa.
D) They were fully bipedal.
E) They were primarily carnivores.

Question 29

What is one of the probable explanations of the extinction of the later australopithecines?

A) They were eventually unsuccessful in competing for available resources with early populations of Homo.
B) The broad-spectrum revolution was not adaptive.
C) They had no social organization.
D) They were a short-lived transitional stage between apes and humans.
E) They are relatively unimportant to the study of human evolution.

Question 30

Which of the following is/are evidence of robust australopithecines' adaptation to eating hard-shelled seeds and grasses?

A) the presence of very large molars and a sagittal crest on the top of the skull
B) fine finger bones and a large mandible
C) massive fossilized temporalis muscles
D) bipedalism, providing the mobility necessary to gather food in open grasslands
E) a small but flexible masseter muscle and an enlarged occipital bun

Question 31

What is the term for the bony protuberance found on top of the skulls of robust australopithecines?

A) temporalis
B) sagittal crest
C) masseter
D) foramen magnum
E) ischium

Question 32

When did the split between the later australopithecines and the ancestors of Homo take place-when they became productively isolated from the later australopithecines?

A) some 6 million years ago
B) when Australopithecus garhi discovered fire
C) they never split
D) some 4 million years ago
E) sometime between 3 and 2 m.y.a.

Question 33

Which of the following statements about the so-called "black skull" is NOT true?

A) The skull shows evidence of cold-weather adaptations.
B) The skull has a sagittal crest.
C) The skull combines relatively small overall size with large chewing dentition.
D) Some scientists categorize the skull as belonging to a very early hyperrobust australopithecine.
E) Some scientists assign the black skull its own species, Au.aethiopicus.

Question 34

Which of the following is NOT discussed in this chapter as a probable cause of the anatomical variety found in the australopithecine fossils?

A) the long time span within which they existed
B) differences in natural selective forces operating in specific environments
C) the poor condition of the fossils
D) age and sex differences
E) random genetic drift

Question 35

Which of the following is NOT considered a direct ancestor of anatomically modern humans?

A) Australopithecus afarensis
B) Homo habilis
C) Homo erectus
D) Australopithecus boisei
E) Australopithecus africanus

Question 36

Australopithecus sediba,a new fossil from South Africa,is considered by some paleoanthropologists to be a bridge between australopithecines and the human lineage.This is because

A) Au. sediba is the oldest fully bipedal ape fossil.
B) Au. sediba shows a mix of ape features and humanlike features.
C) Au. sediba is younger than Homo erectus.
D) Au. sediba had a human-sized brain but still lived in trees.
E) many researchers suspect that there was genetic admixture between Au. sediba and Homo populations.

Question 37

Radiometric dating of South African fossils was not possible because the area was nonvolcanic.

Question 38

What do the skull,jaws,and teeth of australopithecines indicate?

A) Warfare was commonplace, because we see much evidence of head trauma.
B) They were carnivores.
C) They used a fairly complex spoken language.
D) Their diet was largely vegetarian.
E) They were cannibals.

Question 39

All of the following about Au.garhi are true EXCEPT that it

A) was discovered in 1999 in Ethiopia, along with traces of animal butchery.
B) adds a new potential ancestor to the human family tree.
C) made pebble tools around 2.6 m.y.a., challenging the long-held belief that Homo habilis was the first toolmaking human ancestor.
D) displaces Lucy as the most complete skeletal fossil specimen found so far.
E) provides evidence that the thigh bone (femur) had elongated by 2.5 million years ago, a million years before the forearm shortened, to create our current limb proportions.

Question 40

In trying to determine whether a fossil is a human ancestor,we should always look for traits that make us human today.

Question 41

What are the major difficulties that arise in trying to interpret the hominin fossil record? How do these difficulties lead to conflicting interpretations of human evolution?

Question 42

The cranial features of Australopithecus afarensis were poorly adapted to chewing,grinding,and crushing.

Question 43

The genus Homo did not appear until after all of the australopithecines had died off.

Question 44

Identify and discuss the major features of australopithecine dentition.What do these teeth tell us about the australopithecine mode of adaptation?

Question 45

What factors were critical in the evolution of bipedalism? How do they illustrate the close relationship between biology and culture? How does the discovery of Lucy's "baby" contribute to the understanding of this relationship?

Question 46

The footprints at the site of Laetoli in northern Tanzania were made by Australopithecus afarensis.

Question 47

One of the reasons the discovery of the specimen Au.garhi and other materials in its site is important is that it provided evidence that large mammals were being butchered with early stone tool technologies,which suggests the onset of a dietary revolution.

Question 48

Oldowan tools were made by striking flakes off the sides of cores.

Question 49

What are the most significant features of the split between the australopithecines and Homo? How does environmental specialization figure into the equation? What about cultural adaptation?

Question 50

Discuss the place of Ardipithecus kadabba,Ardipithecus ramidus,and Australopithecus anamensis in hominin evolution,considering the current dates associated with both species.

Question 51

Robust australopithecines have been found only in East Africa.

Question 52

The dentition of Australopithecus afarensis exhibits some similarities to the dentition of modern chimpanzees.

Question 53

The teeth and skulls of australopithecines suggest that they had a vegetarian diet.

Question 54

Discuss the significance of Australopithecus sediba.Why do paleoanthropologists debate its place in human evolution? What is unique about this fossil?

Question 55

Sexual dimorphism is less pronounced in modern Homo sapiens than in the australopithecines.

Question 56

Compared to the australopithecines,early Homo had larger cheek teeth and a larger cranial capacity.

Question 57

The oldest known stone tools date from between 2.5 and 2 m.y.a.

Question 58

In apes,the thighbone angles into the hip,permitting the space between the knees to be narrower than the pelvis.