BIOLOGY
OPTIONS
the human story
Worked Examples
CHAPTER 1 Revision Question
1.
Identify technological advances and resulting new information that have changed scientists' opinions
about the classification of primates.
Answer
[Identify means recognise and name]
DNA-DNA hybridisation, haemoglobin comparison, DNA sequencing and the study of
mitochondrial DNA are all technological advances in biochemistry which have led to changing information
and hence changing scientists views on primate classification.
Prior to these technological advances scientists opinions only revolved around fossil evidence and
comparative anatomy, usually indicating a separate evolutionary line for humans compared to apes. Now
scientists have reached different conclusions from new technologies that indicate that chimpanzees and
gorillas are more closely related to humans than orangutans and gibbons. It also suggests that a possible
common ancestor for apes and humans may have lived between 5-10 million years ago.
Marking Criteria
Link two or more technological advances to changing information and scientists
3
opinions
Name two technological advances and give an indication of changing information or
2
changing scientists opinions
Name one technological advance
1
CHAPTER 2 Revision Question
2.
Using examples, describe and distinguish between relative and absolute dating techniques for fossils.
Answer
[Describe means provide characteristics and features]
[Distinguish means recognise or note/indicate as being distinct or different from; to note differences
between]
Relative dating techniques provide accurate information about the sequence in which fossils
appear in the fossil record. Examples of techniques are;
1.
The use of the principle of superposition where a sequence of rock layers (strata) can be dated as
the youngest layer at the top compared to the oldest layer at the bottom.
2.
Stratigraphic correlation is where strata containing similar fossils around the world are presumed
to have been laid down together, and are the same age. Index fossils are commonly used to date
other organisms found in the same layer of rock.
3.
Fluoride-nitrogen dating uses the comparison of the amount of nitrogen lost to fluoride absorbed
to determine age.
All these techniques provide estimates of age. However, absolute dating provides a more accurate method.
Absolute dating is used to determine a numerical value of the age of a material. It uses techniques
such as radiometric dating to calculate the age through the half-life (or rate of breakdown or decay) of
radioactive elements into other elements (for example, uranium, carbon-14 and potassium). Another
technique used is electron-spin resonance which dates an object by measuring the accumulation of higherenergy electrons from natural radiation in the soil over time. Thermoluminescence also dates materials by
measuring the amount of electrons trapped from radioactive elements.
Marking criteria
Description of 2 or more techniques for each of absolute and relative dating and
Marks
5
differences stated between them
Description of 2 or more techniques for each of absolute and relative dating
4
More than one technique listed for each of absolute and relative dating
3
Definition AND differences stated
2
Definition of relative and absolute dating OR basic difference stated
1
Chapter 3 Revision Question
2.
Choose three different hominin examples studied and compare their body structure, cranial
capacity and inferred culture.
Answer
[Compare means show how things are similar or different]
Hominin
Body structure
example
Cranial
Inferred culture
capacity
mL3
Homo habilis
Homo erectus

1.3m in height

40kg

robust

1.7m in height

thick skull

heavy brow ridge

robust build
700

hunters

made and used tools (sharp
flake tools)
850-1000

built shelters

cooperated in groups

hunted large animals, used and
controlled fire

made advanced stone (hand
axe) and bone tools

lived cooperatively in groups

skillful hunters
Homo sapiens

1.6-1.85m in height
(Cro magnon)

70kg (approx. average)

made blade tools

shorter and higher skull

made jewellery, statues, cave

small or no brow ridge
1350
paintings

Similarities

human-like body structure
lived as hunter-gatherers

hunters

made and used stone tools

lived cooperatively
Differences
Homo sapiens

generally taller

much larger cranial capacity

hunter-gatherers (more skillful hunters)

made more advanced tools (blade tools)

made jewellery, statues, caves paintings (more artistic)
Homo erectus

much taller than Homo habilis, with thicker brow ridge and skull

larger cranial capacity than Homo habilis

made more advanced stone tools than Homo habilis.
Marking criteria
Three hominin examples named, correct differences described for all three categories
4
(body structure, cranial capacity and inferred culture) and similarities given between all
three categories.
Three hominin examples named and correct differences described for all three categories
3
(body structure, cranial capacity and inferred culture)
Three hominin examples named and two differences listed
2
Three hominin examples named
1
CHAPTER 4 Revision Question
3.
Define polymorphism and clinal gradation in humans.
Answer
[Define means state the meaning and identify essential qualities]
Polymorphism (the presence in a population of genes that exist in more than one form)
In short, polymorphism in humans is the presence in a population of different forms (or varying in
certain characteristics)
Genes may exist in one or more forms of an allele in a population. When more than one form of a
gene is present, the population is said to be genetically polymorphic.
Many regional differences between human populations have a genetic basis and seem to be
adapted to a particular set of conditions. If certain alleles have become more abundant through a higher
survival rate of individuals, then their abundance today is a result of natural selection.
Basically, polymorphism is the presence in a population of more than one allelic form of a gene.
This has caused different groups of people to have different features.
Clinal gradation (grades of variation)
In short, clinal gradations are continuous blended variations in a species such as humans.
The term 'race' is more specifically used to describe groups of humans occupying different regions
and/or having different cultural practices and beliefs. A considerable amount of geographic gene pool
mixing occurred from prehistoric times onwards to produce clinal gradations that make the grouping of
people into a distinctive 'race' extremely difficult.
Clinal gradations are the existence of transitional groups with overlapping characteristics of two
separate groups. Where the areas occupied by two 'races' meet there is usually a region of overlap where
the characteristics of one 'race' gradually change into the characteristics of the other. People within this
region show characteristics of both 'races' to varying degrees due to the interbreeding at racial boundaries.
Marking criteria
Both terms defined clearly with essential qualities provided
3
Both terms defined simply
2
One correct definition only
1
Chapter 5 Revision Question
2. Explain the development of humans into efficient hunters in organised cooperative groups.
Answer
[Explain means relate the cause and effect; make the relationships between things evident; provide why
and/or how]
As humans evolved physically they began to develop a culture. Cultural development occurs when
skills and ways of life are passed on from generation to generation by communication and tradition rather
than by heredity. Only humans make a deliberate attempt to pass on knowledge, skills and beliefs to others
of their species.
Much of early human culture remains unknown, as it is difficult to preserve such things as
customs or language. Fortunately some cultural items have been preserved such as tools, and more recently,
cave paintings.
Cultural evolution or development has the ability to change rapidly. As a result, human culture is
becoming more and more complex.
The fossil record tells us that early humans were wanderers until about 10,000 years ago. They moved
through their environment in small bands of thirty or less. Their long evolutionary history as nomadic
(wandering) hunters and food gatherers may have played a significant role in stimulating the rapid
evolution of humans, particularly the enlargement of the forebrain, and tool technology. Wandering
humans undergo varied learning experiences rather than those bound to a territory. These learned
experiences would have been communicated to their young through things such as song, dance, and rituals,
over time becoming a cumulative cultural history.
It is thought that the adult males, in bands of twelve or so, would go away to hunt while the adult
females would gather plant material (berries, roots, nuts and seeds). Both sexes would have brought the
food they had acquired back to the camp where it would be shared out amongst the family, or most likely,
the entire group. The hunter-gatherer lifestyle is thought to have originated about four million years ago.
Members would have relied on a diet of mostly plant food, supplemented with meat when hunting was
successful. Neanderthals were hunters. Fossil evidence shows that they hunted woolly mammoths, woolly
rhinoceros and bears that would have provided food during long winters, but also clothing, blankets and
shelter. This food sharing has been suggested to have markedly changed the social structure of early
humans. It would have increased the sense of interdependence between individuals and enabled them to
function more as a social and economic unit. Communication within the group would have been important
and pressure for a spoken language would have increased.
Young males may have learned tool making (from flakes of stone) and hunting techniques from
their fathers or other males in the group, and young women would have watched and helped the older
women gathering food, cleaning hides and making clothes. This passing on of information would have
encouraged the accumulation of knowledge (memory) to use as an adult and pass on to the next generation.
The size of the forebrain, where memories are stored, would have played an important role in human
evolution. Natural selection would have favoured those with large forebrains. Greater capacity for memory,
learning and problem solving is expressed through improved communication, co-operation and inventive
tool making.
Marking criteria
Explain how and why the development of hunting in organised cooperative groups
4
occurred (relate cause and effect)
Explain the development (change) of hunting in organised cooperative groups
3
State how humans hunted efficiently and developed as organised cooperative groups
2
State how humans hunted efficiently or worked in organised cooperative groups
1
CHAPTER 6 Revision Question
1.
Identify one example and analyse the possible effects on human evolution of each of the
following:
-
increased population mobility
-
modern medicine
-
genetic engineering
Answer
[Identify means recognise and name]
[Analyse means identify components and the relationship between them; draw out and relate implications]
Increased population mobility
Cultures that were once isolated have migrated and spread to other countries. With improvements
in transport and travel around the world there has been a dramatic increase in population mobility and
therefore more opportunity for genetic mixing (cross-cultural interbreeding). Over time humans have
developed more flexibility and tolerance of the differences between cultures. It is now possible to say that
the polymorphic variations in humans will disappear because of the genetic mixing through interbreeding
to the point where the existence of separate 'races' becomes extinct.
One disadvantage of this genetic mixing means that blood and organ matching will become more
difficult with the increase in interbreeding and variation of genotypes.
Modern medicine
Medical improvements have resulted in even the weakest members of a population being kept alive
and given opportunities to pass on their genes. These improvements also lead to an increasingly aged
population, which is growing in total. Some examples of modern medicine and their positive or negative
effects are as follows:

Most diseases are controlled by medicine that then increases human life span and creates an
increasingly healthy population.

Vaccination against disease has decreased death rate due to the eradication of diseases in existence and
decrease in occurrence.

Healthier lifestyle awareness has improved areas such as sanitation (drinking water, sewage disposal)
and diet. This decreases death rate and increases life span in the population.

Fewer children are dying at birth and any difficulties can be assisted or prevented (eg. caesarian births,
in vitro fertilisation, amniocentesis) allowing humans to pass on any genetic predisposition.

Surgery such as heart transplants also increase human life span.

Antibiotics are able to destroy bacterial infections and disease, however their overuse is now evident in
the increased resistance of new strains of bacteria.
Genetic Engineering
Genetic techniques have resulted in the ability of humans to alter the gene pool of a population by
technology such as:

Recombinant DNA technology where the genetic makeup of an organism can be altered. For example,
genetic material for protein synthesis is added to bacterial DNA to produce insulin (used by diabetics
to ensure survival). Scientists may also identify and manipulate a gene for aging so people may live
longer without aging.

Cloning - scientists are now able to clone organisms and have the potential to do so with humans. In
1997, the world's first cloned mammal was born. 'Dolly' the lamb was developed from the single body
cell taken from the udder of her mother (donor). This has now opened the opportunity for the cloning
of farm animals and possibly humans.

Testing for the presence of genetic diseases in embryos may result in the elimination of genetic defects
or termination of pregnancies, thus reducing the occurrence of genetic diseases in a population (eg.
amniocentesis is used to test for Down’s syndrome). This may eventuate in the removal of a
predisposition to cancer at embryo stage.

Embryonic stem cells used in organ replacement have caused much moral debate. However, other
sources of stem cells have been identified (cancer cells, bone marrow and brain cells) and the future
holds the possibility of re-growing nerve cells to cure spinal cord injury or diseases such as Parkinson's
and Alzheimer's.

Selective breeding techniques create more efficient production of crops and farm animals resulting in a
greater availability of food for the human population. Concerns have arisen in this area, particularly
with genetically modified foods and the reduced pest resistance occurring in the crops.
Increased mobility, improved medicine and genetic engineering have led to a decrease in death rate,
increase in birth rate and extended life span. This has caused the increase in global human population
numbers. The effects of expanded populations are: overcrowding, starvation (not enough food to supply the
increased numbers), increased stress (poor living conditions) and increased world resource consumption
(pollution, environmental destruction). Fortunately, the global population growth rate has begun to decline.
Marking criteria
Describe an example for each of the three categories and explain two or more possible
6
effects on human evolution
Describe an example for each of the three categories and state one possible effect on
5
human evolution
Describe an example for each of the three categories
4
Name an example for all three of the categories
3
Name an example for two of the categories
2
Name an example for one of the categories
1