Evolutionary trends

Question 1

Describe the trend in the cerebral cortex that has occurred during evolution.

Answer 1

The cerebral cortex has become larger in size and increased in the depth and number of convolutions. In order to store and process the large amounts of sensory information needed due to the increased reliance on vision.

Question 2

What is meant by ‘bipedal with a striding gait’?

Answer 2

Bipedal with a striding gait refers to walking on two feet with the hip and knee being fully extended.

Question 3

Explain why a bowl-shaped pelvis in humans has an advantage for bipedalism over the longer pelvis of other apes.

Answer 3

The bowl shape allows for support of the abdominal organs, requiring less abdominal muscles to hold the organs in place. The bowl shape also provides greater stability for bipedal locomotion and the broad hip bones provides space for the attachment of the large buttock muscles to move the leg and keep the upper body erect.

Question 4

Define ‘carrying angle’ and explain why it allows a striding gait.

Answer 4

The carrying angle is generated by the wide apart hip bones and the convergence of the femurs towards the knees. This arrangement of the femurs forms an angle to the vertical which is called the carrying angle. It allows striding gait as the weight distribution remains close to the central axis of the body when walking. The body is able to be rotated about the lower leg and foot, so each footstep follows a more-or-less straight line.

Question 5

Describe the trend in prognathism during evolution.

Answer 5

Prognathism has decreased due to the reduction in teeth size, the development of a chin and a prominent nose. A flatter face also helps the skull balance more evenly on top of the vertebral column during upright stance.

Question 6

Describe features of fossils of australopithecines that would indicate bipedalism.

Answer 6

A non-opposable robust big toe, the femurs shows convergence towards the knee to create a carrying angle, the pelvic bones show more bowl shape, the foramen magnum is more centrally located and the skull is more rounded at the back. The vertebral column displays an ‘S’ shape curvature.

Question 7

Describe the fingers of both Homo habilis and Homo erectus. Use this to justify which of the two has a more common ancestor with modern humans.

Answer 7

Homo habilis has slightly curved fingers, indicating a strong power grip and the ability to form a precision grip. Homo erectus shows modern finger shape and a fossil discovered showed a styloid process where the fingers meet the wrist, indicating an increase in dexterity and the ability to use powerful and precise grips. Homo erectus has the more recent common ancestor to modern humans.

Question 8

Explain why the forehead of Homo sapiens is rounder and higher than earlier species.

Answer 8

The forehead protects the more developed frontal lobe seen in Homo sapiens.

Question 9

Describe the features of the skull of a Homo sapiens.

Answer 9

The skull of a Homo sapiens is shorter from front to back and are rounder at the back. There are less prominent brow ridges, a reduction in the projection of the face and a smaller jaw. They had a large cranial capacity of 1350cm3. The face is relatively broad and short with the orbits of the eyes well separated. The teeth are smaller and a chin has developed.

Question 10

Neanderthals lived in cold, harsh climates. Discuss two physical features that would have evolved in this environment.

Answer 10

Homo neanderthalensis has a prognathic face with the nasal bones projected forward. This is thought to be an adaptation to the cold and dry environment they lived in. The barrel shaped chest with shorter limbs reduces their surface area to volume ratio, indicating a body stature more adapted for retaining heat.

Question 11

What tool culture did Neanderthals use?

Answer 11

The tool culture associated with Homo neanderthalensis is Mousterian industry.

Question 12

Name and describe the tools used by the Cro-Magnon.

Answer 12

The Cro-Magnon people used blade tools – flakes of stone with roughly parallel sides.

Question 13

Australopithecus afarensis cranial capacity, time existed, tool culture, features, place

Answer 13

4-3 million years ago
430 cm3
Opportunistic Oldowan tools (pebble tools)
East Africa

Question 14

Australopithecus africanus cranial capacity, time existed, tool culture, features, place

Answer 14

3.2-2 million years ago
480 cm3
Opportunistic Oldowan tools (pebble tools)
Southern Africa

Question 15

Paranthropus robustus cranial capacity, time existed, tool culture, place

Answer 15

2.8-1.4 million years ago
520 cm3
Opportunistic Oldowan tools
South Africa

Question 16

Homo habilis cranial capacity, time existed, tool culture, place

Answer 16

2.3-1.5 million years ago
610 cm3
Oldowan tools
Southern Africa

Question 17

Homo erectus cranial capacity, time existed, tool culture, place

Answer 17

2 million-100,000 years ago
1050 cm3
Acheulin tools (flaked around edges, tear-drop)
Africa, Eastern Europe, SE Asia

Question 18

Homo neanderthalensis cranial capacity, time existed, tool culture, place

Answer 18

300,000-28,000 years ago
1485 cm3
Mousterian culture (stone flakes that were shaped)
Europe, South western to central Asia

Question 19

Homo sapiens cranial capacity, time existed, tool culture

Answer 19

300,000 years ago-present
1350 cm3
Aurignacian tools
Solutrean culture
Magdalenian culture

Question 20

Primate features

Answer 20

Relatively large, complex brains, forward-facing eyes (stereoscopic vision), grasping hands with long fingers to curl around objects, flat nails, long childhood that extends well beyond weaning.

Question 21

Human and ape classification

Answer 21

Kingdom - animalia
Phylum - chordata
Class - mammalia
Order - primates
Family - hominidae

Question 22

Difference between hominids and hominins

Answer 22

Hominids include humans and great apes. Hominins are those primates for which bipedalism is the normal walking habit (includes modern and ancestral humans).

Question 23

Power grip vs precision grip

Answer 23

Power - folds the fingers around an object and holds it tight (holding a hammer).
Precision - uses the fingertips and thumb (using a pen).

Question 24

What primate group has a precision grip?

Answer 24

Homo

Question 25

Advantages of being bipedal

Answer 25

Frees up hands to carry food, offspring, use tools and weapons.
Eyes are higher above the ground so predators or carcasses can be seen from further distances.
Air is cooler above the ground so the body would be cooler. Less area of the body surface would face the sun at midday too.
Walking on two legs is more energy efficient than movement on four legs.

Question 26

How does dentition influence skull structure?

Answer 26

Dentition shapes the size and amount of prognathism of the jaw. The smaller the teeth and more parabolic the arcade, the less prognathism.

Question 27

What evidence is there to suggest that Homo erectus could speak?

Answer 27

H. erectus has both the Broca’s area and Wernicke’s area in the cerebral cortex a shown by indentations on the internal surface of the skull. The Broca’s area is concerned with speech production and the Wernicke’s area is concerned with the interpretation of speech.

Question 28

What advantages would the addition of meat to their diet be?

Answer 28

Meat is high energy and once was a regular part of their diet, could spend less time foraging for food and thus had time to refine and develop tools.
With meat and fire, could also migrate and live in colder climates.
Could have enhanced social behaviour and speech development as communication between members was needed to take down large animals.

Question 29

Explain how the use of tools in early Hominins spurred the development of a change in the way of life of our ancestors.

Answer 29

Basic tools essential for butchering large animals (human teeth and fingers not good enough for cutting through tough skin and meat).
More specific tools came through experimentation and chance.
Tool-making was a learnt skill, so needed to have groups where tool-makers taught others or social interactions with other groups to pass on tool-making knowledge.
Hunting techniques became more successful, increasing food supplies so more people could live together in the group.
Had to know the locations of tool-making stones and needed to go there on a regular basis to make new tools or live close to these locations in a less nomadic way.

Question 30

Levallois technique

Answer 30

Process of producing a flake from a stone core, normally had a flat side and a sharp cutting edges.
Levallois technique is slow, requires planning and foresight → significant cognitive development.

Question 31

Oldowan tools.

Answer 31

Used by Homo habilis. Were pebble tools, including choppers, scrapers, flakes and chisels. Used to scavenge meat from carcasses and breaking open bones to access bone marrow.

Question 32

Acheulian tools.

Answer 32

Used by Homo erectus. Tools were flaked around all the edges to form bi-faced lumps, tear-drop in shape. They were used as hand axes and were used to hunt and butcher animals.

Question 33

Mousterian tools.

Answer 33

Used by Homo neanderthalensis. These tools were manufactured using the Levallois technique. Is a slow, labour-intensive process requiring planning and foresight. Tools could be hafted, broadening the use and increased effectiveness of the tools.

Question 34

Aurignacian, Solutrean and Magdalenian tools.

Answer 34

Used by Homo sapiens. Aurignacian tools are blade tools, effective in cutting and easy to handle. Solutrean culture are laurel-lead and willow-lead points made by carefully retouching blades made by pressure flaking. Would have taken hours of intricate skill to produce. Magdalenian culture is known for the dominance of bone and antler tools. Bone and antler tools were produced by a burin, a tool used to manufacture other tools.

Question 35

Mousterian vs Acheulian tools.

Answer 35

Mousterian tools are produced from the Levallois technique, where a piece of stone is trimmed into a disc-shaped core, and then struck by another piece of stone to produce flakes that were flat on one side and had sharp edges.
Acheulian tools are produced by flaking all around the edges, first in one direction then in the other until they formed a two-faced lump, approximately teardrop in shape.

Question 36

Describe two features of the tools that would provide support for the fossilised footprint belonging to Homo neanderthalensis.

Answer 36

Stone tools that were notched/toothed/denticulated
Stone/flakes that were attached or hafted to wood
Tools made of other materials such as ivory, bone and antler
Greater variety of tool types

Question 37

Describe two less advanced features that these tools would have shown to indicate that they were older than the tools attributed to Homo neanderthalensis.

Answer 37

Pebble tools
Flake and core tools
Hand axe
Less flaked/notched

Question 38

Explain one advantage an increased brain size gave to early Homo sapiens to enable them to survive in their environment in reference to the association, motor and sensory function areas of the cerebral cortex.

Answer 38

Association: Improved memory of food/water sources, improved ability to plan hunts
Motor: Improved muscle control for hunting/improve fine motor skills for tool making
Sensory: Improved sensory perception for hunting/perceiving danger

Question 39

Name the two curves at the top and bottom of the spine and then explain their function.

Answer 39

Cervical Curve - Improves body balance in upright position and enables the head to balance on top of the neck
Lumbar Curve - Brings the vertebral column directly under the centre of gravity

Question 40

How have the changes to the jaw and dental arcade provided advantages?

Answer 40

better balance of head on neck for upright position / reduction in associated neck muscles / speech / more omnivorous diet that offers greater energy / more protein for brain development

Question 41

Describe the structures the scientists would have observed to determine
which skeleton is the ape.

Answer 41

Smaller cranial capacity
Foramen magnum towards back of skull
C shaped spine
Highly prognathic face
Long narrow pelvis
No carrying angle at knee
Smaller knee joint/ medial condyle larger than outer condyle
Longitudinal arch in foot only
Smaller heel
Diastema present
U-shaped dental arcade
Large canines
Opposable big toe