1. Topic: Human Evolution
Gr.12 Life Sciences
Topic: Human Evolution

2. Human Evolution

3. TERMINOLOGY
Give the correct biological term for each of the following descriptions.
Write only the term next to the question number (1.1 to 1.10).
1.1 The development of new species from existing species.
1.2 A study of the distribution of organisms in different parts of the world.
1.3 Similar structures in different organisms indicating common ancestry.
1.4 Having a pointed face because of projecting jaws and nose.
1.5 A group of similar organisms that can breed to produce fertile offspring.
1.6 A group of organisms of the same species that occupy a particular habitat.
1.7 Only organisms with favourable characteristics survive.
1.8 Using parents with particular desirable characteristics to obtain a combination of these desirable characteristics in the offspring
1.9 An opening in the skull through which the spinal cord passes
1.10 Locomotion involving the use of a pair of hind limbs only

4. ANSWERS 1.1 Speciation 1.2 Biogeography 1.3 Homologous 1.4 Prognathous
1.5 Species
1.6 Population
1.7 Natural selection
1.8 Artificial selection
1.9 Foramen magnum
1.10 Bipedal

5. Similarities between Homo Sapiens and other primates
Large brains/skulls compared to their body mass
Eyes with cones /colour vision
Eyes in front/binocular vision/stereoscopic vision
Eyes with cones/colour vision
Two mammary glands only
Freely rotating arms
Long upper arms
Elbow joints allowing rotation of forearm
Flat nails instead of claws/bare finger tips
Upright posture
Opposable thumbs which work in opposite direction to their fingers

6. Structural characteristics of Homo sapiens that are similar to other primates.
Upright posture
Long upper arms
Eyes with cones /colour vision
Rotate hands at least 180º
Flat nails instead of claws/bare finger tips
Opposable thumbs which work in opposite direction to their fingers
Sexual dimorphism/distinct differences between male and female
Olfactory brain centres reduced/reduced sense of smell
Parts of the brain that process information from the hands and eyes are enlarged
Two mammary glands only

7. Characteristics that make us different
Homo sapiens
Other primates
Larger cranium/brain
Smaller cranium /brain
Face sloping/Forehead slope less backwards
Flat face/ Foreheads slope much backwards
Foramen magnum bottom of the skull
Foramen magnum at the back of the skull
Lower jaw has a well developed chin
Lower jaw has poorly developed chin
More protruding jaws
Less protruding jaws/prognathous
Smaller canines
Larger canines
Smaller spaces between the teeth
Larger spaces between the teeth
Brow ridges are not as pronounced
Brow ridges pronounced
Jaws with teeth on a gentle/round curve
Jaws with teeth in a rectangular/U shape

8. QUESTION
Study the diagrams below of the upper jaw, skull and the foot of two organisms A and B. The diagrams are NOT drawn to scale.
With regard to the drawings above:
(a) Tabulate TWO visible differences between the upper jaws of organisms
A and B (5)
(b) Name ONE visible difference between the feet of organisms A and B (2)
2. Which organism (A or B) is more likely to be bipedal? (1)
3. Give a reason for your answer to QUESTION (2)

9. ANSWERS
1(a)

10. ANSWERS 1(b) Differences in Feet: 2. A ✓
In A the big toe is close to the other 4 smaller toes and points forward ✓
In B the big toe is apart from the other 4 smaller toes and points outwards✓ OR
In A the heel bone is relatively larger ✓ and in B it is relatively smaller ✓
In A the bones in the foot are straight ✓ and in B they are curved ✓
In A phalanges are relatively shorter ✓and in B they are relatively longer ✓
any 1 x 2 (Mark first ONE only) (2)
A ✓
Foramen magnum ✓more towards the centre ✓ of the skull in A / more
forward
In B the foramen magnum✓ more towards the back✓ of the skull (2)

11. Interpret evolutionary trends using phylogenetic trees and cladograms
Our place in the animal kingdom
Interpret evolutionary trends using phylogenetic trees and cladograms
A SIMPLIFIED SUMMARY OF THE HISTORY OF HOMINIDS
Homo erectus
Homo habilis
Homo sapiens
A. robustus A B
Chimpanzee
Time (million years)
Australopithecus
afarensis

12. QUESTION
The diagram below shows a phylogenetic tree based on DNA similarities. The percentage next to each branch shows the amount of difference in the genome (DNA nucleotide sequence) of the two relevant groups.
1.From the diagram, determine how long ago the chimpanzees split from the line to humans (2)
2. Which organism is most closely related to humans? (1)
3.Calculate the DNA similarity between the genome of the chimpanzee and the human (2)

13. ANSWERS
P mya ✓ (1)
2. Chimpanzee ✓ (1)
,6 ✓% ✓ (2)

14. Trends in Human Development
Shift of foramen magnum to a more forward position
A more rounded skull and Increased cranium size
A flatter face due to:
Less sloping forehead
Less protruding jaws
(decreased prognathous)
A more developed chin
A more rounded jaw
Increased size of skeleton
Change in dentition
More rounded head
Identify on skull

15. Primate Fossils
Australopithecus Homo erectus Homo sapiens

17. The contribution of African fossils to the understanding of human evolution
Fossils found in the Cradle of Humankind and scientists' interpretation of these fossils.
Fossils found in the Great Rift Valley an their interpretation (Nutcracker man, Handy man, Toumai).

18. The “Out of Africa’ hypothesis
According to most scientists, humans originated from Africa and moved to other countries.
This hypothesis is based on fossil evidence and genetic evidence from fossils of Africa.
When DNA is analysed for the purpose of tracing ancestry, a search is made for mutations since individuals who have the same mutation must share the same common ancestor.
These mutations serves as markers of decent DNA from Y chromosome AND Mutant genes from Mitochondrial DNA.

19. The 'Out of Africa' hypothesis
Fossil evidence for the 'Out of Africa' hypothesis (Mrs Ples, Taung child, Little foot, Karabo,
Nutcracker man, Handyman, Toumai)
Migration of Homo erectus from Africa into the rest of the world Genetic evidence for the “out of Africa' hypothesis (DNA from Y chromosomes and mitochondrial DNA)

20. The contribution of African fossils to the understanding of human evolution
Mrs. Ples (Australopithecus africanus), Found at Sterkfontein caves by Robert Broom in million year-old fossil)
Little foot (Australopithecus africanus), 3.9 to 4.2 million year-old fossil. Discovered by Ron Clark with the assistance of Steven Motsumi and Nkwane Molefe Sterkfontein Caves, July 1997 on the tibia was found. In October 2006 the fossil was brought to the surface.
Taung child, (Australopithecus africanus), Found at Taung ( North West Province) in 1924 by Raymond Dart. It’s a 2.6 to 2.8 million year-old fossil.
Karabo(Australopithecus sediba) .Found at Malapa site in Cradle of Humankind by Lee Berger in April million
year-old fossil, regarded as the missing
link between Australopithecus africanus.

21. Scientific interpretation of the African fossils found at the Cradle of Human kind
The scientific value of ‘Cradle of humankind’ lies in the fact that these sites provide us with a window into the past, to a time when our earliest ancestors were evolving and changing. Scientists have long accepted that all humans had their origins in Africa. Through the use of biochemical evidence they have argued that the split of the human lineage (Hominidae) from that of the African apes took place around 5-6 million years ago.

22. Fossils found in the Great Rift valley
Nutcracker man (Paranthropus boisei). Appeared 1.2 to 2.2 million years ago. Fossil found by Mary and Louis Leaky in 1959 in Tanzania.
Handy man (Homo Habilis) Earliest species of Homo Discovered by Peter Nzube in 1968 in Tanzania.
Lateoli footprints, Found by Mary Leaky at Tanzania, 3600 million-years old in 1978.
Toumai (Sahelanthropus tchadensis). Found by Michael Brunet in Chad in 2001.

23. Scientific interpretation of Nutcracker man, Handy man, Toumai
Based on the fossil find in the Great Rift valley scientist thought of it as the cradle.
This is because in 2001, the cranium of a 7 million year old fossil of Toumai was discovered in the central African country of Chad.
The idea that our earliest ancestors had a southern or east African origin has been overturned.
Now scientists believe that the cradle o human kind was Central Africa
How long this idea will last depends on whether an older hominid fossil is found anywhere else in the world

24. Out of Africa hypothesis

25. QUESTIONS
Study the table below, which indicates some of the hominid fossils found in different parts of the world. 1. 2
Explain why the information in the table supports the 'Out of Africa' hypothesis.
Describe how the analysis of mitochondrial DNA is used to support the 'Out of Africa' hypothesis.
(2)
(3)
(5)

26. ANSWERS
1. The oldest fossils of human ancestors were only found in Africa (2)
2. Mitochondrial DNA is passed down from mother to child
Mutations on the mitochondrial DNA
were traced to an ancestral female that existed in Africa (3)