1 Identify the following statements as true or false a Robert Broom discovered the first fossil Australopithecus africanus




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Chapter 15
Answers QUICK-CHECK questions

1 Identify the following statements as true or false.

a Robert Broom discovered the first fossil Australopithecus africanus.

False: Robert Broom discovered fossil hominins, including fossils of Australopithecus africanus, but Raymond Dart discovered the first fossil belonging to that species.



b The Taung child fossil was a member of the genus Homo.

False: While the Taung child fossil is recognised as an early hominin, it does not belong to the genus Homo; it is a species within the genus Australopithecus.



c The position of the foramen magnum can indicate whether a species walked upright or not.

True: The foramen magnum is the hole in the base of the cranium where the spinal cord leaves the brain; the position of the foramen magnum provides an indication of whether or not a species could walk upright. Walking upright is indicated when the foramen magnum is located near the middle of the base of the cranium rather than near the back.



d In an erect-walking species, the femur and the tibia do not join in a straight line.

True: In an erect-walking species, the femur (thigh bone) is at an angle to the tibia (shin bone).(See figure 15.7.)



2 List two reasons why the Taung fossil skull was not immediately accepted as a link between humans and ancestral species.

The Taung fossil was not immediately accepted as a link between humans and ancestral species because this fossil did not fit the prevailing view of experts of that time:



  • The Taung fossil was found in Africa rather than in Asia where human ancestors were then believed to have originated.

  • The fossil had a small brain capacity rather than being large-brained as then predicted.

Both the Taung fossil and subsequent fossil evidence provided evidence that the prevailing views of that time were indeed incorrect.

3 Identify a famous hominin fossil linked with the following names:

a Raymond Dart

The Taung child (Australopithecus africanus)



b Donald Johanson

‘Lucy’ (Australopithecus afarensis)



c Robert Broom

Paranthropus robustus (also known as Australopithecus robustus)

4 Identify the following as true or false.

a Chimpanzees have skeletal features that equip them for routine upright walking.

False: The skeleton of a chimpanzee does not equip it to walk upright routinely. Neither the position of the foramen magnum towards the back of the base of the cranium (like that of the gorilla) nor the straight line arrangement of the femur and the tibia is consistent with routine upright walking.



b The ability of hominins to walk upright appeared before brain enlargement had occurred.

True: The skeletal features that are evidence of upright walking are seen in fossil hominins at an earlier date than the appearance of brain enlargement (that is inferred from enlargement of the cranium).



c All primates have the characteristic features of mammals.

True: Since all primates are mammals, they display the features that are characteristic of mammals, including the presence of mammary glands and hair covering on body.

(Note: Other features that are characteristic of all mammals are shown in figure 15.10.)

5 A monkey would be expected to have a greater brain mass than a dog with the same body mass.

True: Monkeys are members of the order Primates and they are characterised by a higher brain to body mass ratio than that seen in non-primate mammals.



6 Identify one feature that you would expect to see in the skull of an extinct hominin species.

The skull (comprising the cranium and the lower jaw) would display many features, some being typical of all mammals, some being typical of all primates and some being seen only in hominins. These include:



  • mammalian features:

  • primate feature:

  • large and forward-facing eye sockets

  • hominin features:

  • foramen magnum located near centre of the base of the cranium

  • large cranial capacity relative to estimated body mass.

7 List three features that are characteristic of primates.

Features characteristic of primates include:



  • five digits on hands and feet

  • opposable thumb on hands and/or big toe on feet

  • flat nails on tips of digits

  • forward-facing eyes (giving binocular vision)

  • large brain relative to body mass

  • ability to rotate arm in shoulder socket

  • longer gestation period than non-primates

  • typically live in social groups

  • provision of parental care for extended period after birth.

(Note: No single feature alone can be used to identify a primate; rather, it is the collection of these features that is used to identify a primate.)

8 What is a power grip?

A power grip is the typical grip of the human hand when exerting force on a held object. This is in contrast to the precision grip that enables precise and delicate manipulation.



9 Identify the following as true or false.

a The line that gave rise to Old World monkeys diverged from the ape line about 5 to 7 million years ago.

False: This divergence is estimated to have occurred about 30 million years ago (see figure 15.4).



b The oldest monkey fossil would be expected to be more recent than the oldest ape fossil.

False: Monkeys preceded the evolution of the apes, so the oldest (earliest) monkey fossil would be expected to be older than the oldest (earliest) ape fossil.



c Humans evolved from chimpanzees.

False: Humans did not evolve from chimpanzees but they shared a common ancestor. The line that led to the human species diverged (split) from the line that gave rise to modern chimpanzee species about 5 to 7 million years ago.



d The line that gave rise to modern gibbons diverged from the ape line before the orang-utan line.

True: Estimates indicate that the line that gave rise to modern gibbons diverged from the great ape line about 18 million years ago, while the line that gave rise to modern orangutans diverged later, about 14 million years ago.



10 Outline how Sarich and Wilson obtained an estimated time of divergence of the human line from the non-human line.

Sarich and Wilson estimated the time of divergence of the human line from the non-human ape line by studying the number of changes in the corresponding protein in human and in non-human ape species. Their technique assumed that the rate of change in a given protein was constant over time so that the number of changes could be used to estimate the time that the two evolutionary lines separated.



11 Identify the following as true or false.

a Hominins of the genus Ardipithecus lived before hominins of Lucy’s species.

True: Hominins of the genus Ardipithecus lived before hominins belonging to the genus Australopithecus (see figure 15.27).



b Fossils of the genus Homo will be younger than A. afarensis fossils.

True: Australopithecus afarensis evolved before the appearance of the first members of the genus Homo.



12 List two hominin fossils discovered by a member of the Leakey family.

Hominin fossils discovered by members of the Leakey family include:



  • Homo habilis (Jonathon Leakey)

  • Australopithecus (Paranthropus) boisei (Mary Leakey)

  • Kenyanthropus platyops (Maeve Leakey)

13 Identify the following statements as true or false.

a The fossil record contains just one species of Australopithecus.

False: Many species within the genus Australopithecus have been discovered, including A. afarensis and A. africanus.



b The upper jaw of an australopithecine is identical with that of the chimp.

False: The upper jaw of a chimp is box-shaped compared with the more rounded shape of the upper jaw of an australopithecine, and the chimp has larger canine teeth (see figure 15.28).



c From an examination of the zygomatic arch on a fossil skull, it is possible to draw conclusions about the strength of the bite of the species.

True: One important muscle that closes the jaw when we chew or bite passes from the jaw through the space behind the zygomatic arch to the top of the skull. The size of this space indicates the size of this muscle and gives an indication of the strength of a bite — the larger the space, the larger the muscle and the stronger the bite.



d The various australopithecine species lived in similar habitats.

False: Evidence, including the identity of other plant and animal fossils that were found in the same region as various australopithecine fossils, indicates that these species lived in different habitats.



14 What evidence, if any, exists for tool use in the australopithecines?

Bones, smashed probably by use of stones, have been found and have been dated to the same age as Australopithecus fossils found in the same region. These findings provide evidence suggestive of tool use by australopithecines.



15 Identify the following as true or false.

a H. erectus appeared earlier in the fossil record than H. habilis.

False: Homo habilis appeared earlier in the fossil record than H. erectus. The earliest fossils of H. habilis have been dated to about 2.4 million years ago, while the earliest H. erectus fossils have been dated to about 2 million years ago.



b When the first human species appeared, all the australopithecines were extinct.

False: The first human species, Homo habilis, appeared in the fossil record about 2.4 million years ago. At that time, some robust australopithecines were still in existence including Paranthropus (Australopithecus) robustus and Paranthropus (Australopithecus) boisei. (See figure 15.27.)



c The term ‘Acheulian’ refers to the stone tools made by H. erectus.

True


d A ‘splitter’ would separate H. erectus into two species: H. ergaster and H. erectus.

True: So-called ‘splitters’ recognise more hominin species than so-called ‘lumpers’.



16 Name the following:

a the first hominin species to make controlled use of fire

The first hominin to make controlled use of fire was Homo erectus.



b the first hominins to eat meat as a major component of their diet

The first hominins to eat meat as a major component of their diet were Homo habilis.



c the term to describe the simple tools made by the habilines

Tools made by Homo habilis are termed Oldowan tools.



d the first human species to leave Africa.

The first human species to leave Africa was Homo erectus.



17 Identify three physical differences between H. heidelbergensis and H. sapiens.

Physical differences between H. heidelbergensis and H. sapiens include:



  • prominent brow ridges present in H. heidelbergensis but absent in H. sapiens

  • forehead more sloping in H. heidelbergensis than H. sapiens, in which the forehead is more vertical

  • larger teeth in H. heidelbergensis than H. sapiens

  • chin absent in H. heidelbergensis but present in H. sapiens

  • skull (cranium) more rounded in H. sapiens than H. heidelbergensis.

18 Identify one difference between the nineteenth century view of human evolution and that of the twenty-first century.

A view held in the nineteenth century was that evolution to modern humans was a straight line with a ‘missing link’ between modern humans and their common ancestor with the other great apes.

(Note: Until the 1960s, the view was that this common ancestor last existed at least 30 million years ago.)

19 What is meant by the ‘out-of-Africa’ hypothesis?

The ‘out-of Africa’ hypothesis is the view that modern humans evolved in Africa and migrated from there to other regions, including present day Europe and Asia (see figure 15.56).



20 Where is the ‘Fertile Crescent’?

The ‘Fertile Crescent’ is a crescent-shaped area of the Middle East that today includes Israel, Syria and Iraq, and the major rivers are the Tigris and the Euphrates.



21 Identify two differences between a food-gathering lifestyle and a food-producing lifestyle.

Differences between a food-gathering style and a food-producing lifestyle include:



  • A food-gathering lifestyle is nomadic, whereas a food-producing lifestyle involves permanent settlements.

  • A food-producing lifestyle is associated with higher population densities than for a food-gathering lifestyle.

  • A food-producing lifestyle enabled the build-up of surplus food stores, whereas food gathering is a less efficient means of obtaining food.

  • A food-producing lifestyle supports a more diverse and complex social structure than that of a food-gathering lifestyle.

  • People in a food-producing society have more time and opportunity for creative pursuits that people in a food-gathering society.

22 Identify the following as true or false.

a Nomadic societies have more complex social structures than sedentary societies.

False: Nomadic societies (hunter/gatherers) have a less complex social structure than sedentary (food-producing) societies, because nomadic societies are smaller, do not have permanent settlements and have far less opportunity for division of labour.



b Agricultural practices developed at the same time worldwide.

False: Evidence shows that the domestication of local wild animals and the cultivation of local wild plants did not occur simultaneously worldwide.



c Selective breeding practices were used by nomadic hunter-gatherers.

False: Nomadic hunter-gatherers hunted wild animals and did not use selective breeding. Selective breeding practices were used in food-producing societies.



d The cultivation of wild rice began in the Fertile Crescent.

False: Plants that were first cultivated in the Fertile Crescent included wild wheat, wild barley and wild peas. Conditions were not suitable for wild rice.



23 Identify the following statements as true or false.

a In a tropical rainforest, people with a tall thin body shape are at a selective advantage to other shapes.

False: In a hot, dry, open environment with good air flow, a tall thin body shape with a high surface area to volume ratio is able to lose heat effectively and is at a selective advantage relative to other body shapes. However, in a tropical rainforest, conditions are hot, humid, closed and without good air flow; under these conditions, a tall thin body shape is not at a selective advantage relative to other shapes. (See pages 609–10.)



b Lactose-intolerant people are selected against in all environments.

False: Lactose-intolerant persons would be selected against only in those environments in which lactose was a common dietary component, such as in human groups that domesticated cattle and used their milk.



c Phenotypes at a selective advantage in one environment will be at the same advantage in other environments.

False: One specific phenotype will be at a selective advantage (or be the ‘favoured’ phenotype) only when it is in an environment where a particular selection pressure acts on other phenotypes in the population reducing their survival and rate of reproduction. However, this selective advantage is lost if the favoured phenotype moves into a new environment where that particular selection pressure no longer acts.



d Adaptations of humans to life in cold climates include wide hips and short, thick limbs.

True: In contrast to narrow hips and long thin limbs, these physical features (wide hips and short thick limbs) reduce the surface area to volume ratio of the human body, thus reducing heat loss and conferring a selective advantage in cold climates.



24 Give one example of a polymorphic trait in a human population.

Examples of polymorphic traits in human populations include:



  • ABO blood types

  • Rhesus blood types

  • lactose tolerance/intolerance

  • beta thalassaemia.

25 Give one example of a clinal gradation in human populations.

A clinal graduation is a gradual change in a trait across a geographic range, such as from the equator to the poles or from sea level to a mountain top. Examples of clinal graduations in human populations include:



  • changes in skin pigmentation of indigenous populations from dark in equatorial regions to very light skinned in high latitudes

  • changes in body shape with latitude and climate.

26 Identify two ways in which biological evolution differs from cultural evolution.

Biological evolution:



  • is a slow process in which transmission occurs via DNA

  • occurs only from parents to offspring

  • acts from one generation to the next with no choice of traits to be transmitted.

Cultural evolution:

  • is a much faster process in which transmission is through written spoken or signed language

  • can occur between unrelated persons and within one generation

  • allows choice about what is accepted by an individual.

(See table 15.12.)

27 Give one example of cultural evolution or cultural change in communication.

Examples of cultural change in communication over human history include replacement of:



  • symbols on clay by symbols on parchment

  • parchment (vellum) by paper

  • town crier for news dissemination by radio broadcasts that reached a much wider audience

  • handwritten manuscripts by printed material produced en masse

  • letters by emails

  • written communication by spoken communication via telephone.

Each of these changes has been a result of technological evolution.

28 Give one example of how technology has extended human capabilities.

Examples of how technology has extended human capabilities include the use of:



  • optical telescopes to visualise distant galaxies that would otherwise remain unseen

  • microscopes to see microscopic objects invisible to the unaided human eye

  • motorised vehicles/crafts to enable much faster travel than unassisted human movement

  • cranes to lift objects beyond the scope of unassisted human capability

  • submarines and rockets to move into environments outside the range of unassisted human survival

  • telephones to communicate with people at a distance from the speaker.


29 Give one example of an interaction between biological, cultural and technological evolution.

An example of an interaction between biological, cultural and technological evolution is tool making.

Biological evolution contributed to tool making because it led to:


  • bipedal upright walking in hominins, which freed the hands

  • increased brain capacity, which enabled solving of more complex problems.

Cultural evolution/change was the development of tool making in early human species, initially based on the use of stone tools to make tools.

Over time, tool-making technology evolved so that new materials, including metals, were used both in tool making and in new kinds of tools that were fashioned.



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