VARIATION, GENETIC ENGINEERING, CLONING AND EVOLUTION
Q1.
The diagram shows one way of cloning sheep.
Use words from the box to complete the sentences.
asexual clones different gametes
identical joining
sexual
splitting
The original embryo in the diagram developed following the ....................................... of an egg
and a sperm. This is called ..................................... reproduction. The twins in the diagram have
..................................... genetic information. This is because the two embryos were produced by
..................................... reproduction. Because of this they are known as
.....................................
(Total 5 marks)
Q2.
A market gardener produces large numbers of attractive, large flowered geranium plants.
(a)
Give two advantages to the gardener of producing geraniums from cuttings rather than
from seeds.
1 ..................................................................................................................................
.....................................................................................................................................
2 ..................................................................................................................................
.....................................................................................................................................
(2)
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(b)
Gardeners often cover trays of cuttings with large polythene bags.
Suggest one advantage of this.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 3 marks)
Q3. The drawing shows a potato plant producing new tubers (potatoes). Buds on the stem of the
parent plant produce stolons. The new tubers are formed at the ends of the stolons (stems that
grow downwards).
(a)
Explain why the new tubers are genetically identical to each other.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Some of the tubers are used to produce potato plants. These new potato plants will not
all grow to the same height.
Give one reason why.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 3 marks)
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Q4.
The diagram shows one method of producing herbicide-resistant crop plants.
(a)
(i)
The herbicide-resistance gene is obtained from a herbicide-resistant plant.
Which structure in a cell carries the genes?
...........................................................................................................................
(1)
(ii)
How is the herbicide-resistance gene cut out of this structure?
...........................................................................................................................
...........................................................................................................................
(1)
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(b)
Apart from having the herbicide-resistance gene, the herbicide-resistant plants are
identical to the herbicide-susceptible plants.
Explain why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(c)
Suggest one advantage to a farmer of growing herbicide-resistant crops.
.....................................................................................................................................
.....................................................................................................................................
(1)
(d)
Many people are opposed to the growing of herbicide-resistant crops produced in this
way.
Suggest one reason why.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 6 marks)
Q5. The peppered moth is an example of a mutation which gives the mutant variety an advantage in
certain environmental conditions.
Normally the peppered moth is light coloured.
In 1848 the first dark form of the peppered moth was caught in the Manchester area. By 1895,
98% of the population was the dark form. In an area where a smokeless zone was established
in 1972 the percentage of light-coloured peppered moths changed. In 1961 it was 5.2% but in
1974 it had risen to 10.5%.
Use the information above to explain the term natural selection.
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...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
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(Total 4 marks)
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Q6.
The theory of evolution via natural selection was proposed by Darwin.
(a)
Explain how evolution occurs via natural selection.
........................................................................................................................
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........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................
(4)
(b)
Darwin’s theory was only gradually accepted.
Give two reasons why.
1 .....................................................................................................................
........................................................................................................................
2 .....................................................................................................................
........................................................................................................................
(2)
(Total 6 marks)
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M1.
joining
1
sexual
1
identical
1
asexual
1
clones
1
[5]
M2.
(a)
quick
cheap / many can be produced from one plant
cuttings produce plants identical (to parents) / outcome known
any two for 1 mark each
2
(b)
idea that provides damp atmosphere / less likely to wilt
reduces or stops transpiration or water loss / keeps it warmer
(reject prevents animals eating it)
for 1 mark
1
[3]
M3.
(a)
grow from parents,
by vegetative reproduction/asexual reproduction/
no sexual reproduction
for 1 mark each
2
(b)
e.g. different environmental conditions/named condition
for 1 mark
1
[3]
M4.
(a)
(i)
chromosomes
allow DNA
ignore nucleus
1
(ii)
enzymes
1
(b)
asexual reproduction / no gametes / no fusion / only one parent
ignore clones
1
cells all contain same genetic information / same genes (as parent) / same DNA
1
(c)
can spray crop with herbicide – only weeds killed
crop survives herbicide insufficient
1
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(d)
any one from:
•
fears / lack of knowledge about effects of GM food on health
allow ‘think that GM food is bad for health’
ignore not natural or against religion
•
crop plants may pass on gene to wild plants
•
encourages use of herbicides
1
[6]
M5.
any four from
dark were better adapted to survive or
dark ones can hide in dirty environment
dark is the survival of the fittest or they are better camouflaged
those which survive breed
they are able to pass on their genes
light ones more easy to see on smoky
surfaces (so get eaten)
birds can see light ones more easily
as environment becomes cleaner or less
smoky light ones hide easier
those which survive breed or increase
the population
accept the converse argument
[4]
M6.
(a)
organisms within species may show variation
1
because mutation(s) occur in individuals
1
this results in the individuals with characteristics most suited
to the environment being more likely to survive / to breed
1
as a consequence the genes that have enabled these
individuals to survive are passed on to the next generation
1
(b)
any two from
•
the theory undermined the idea that God made all the animals
and plants that live on earth
•
there was insufficient evidence at the time
•
the mechanism of inheritance / variation was not yet known
2
[6]
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