4 marksFig. 1 shows a group of male students. They are all the same age.
Fig. 1
(i)
The students in Fig. 1 show continuous variation in some of their characteristics.
State three characteristics in which these students show continuous variation.
[3]
(ii)
State one example of discontinuous variation.
[1]
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2 marksSelective breeding of animals is very important to farmers.
Many different breeds of sheep have been produced by selective breeding.
Fig. 1 shows a flock of Merino sheep. This breed of sheep was produced by selective breeding.
Fig. 1
Sheep are important animals in many parts of the world as they produce meat, wool and milk.
Table 1 describes some characteristics of five different breeds of sheep.
Table 1
breed of sheep | wool yield | wool quality | meat yield | milk yield |
Arapawa | average | good | poor | average |
Awassi | average | poor | average | very good |
Blackbelly | poor | poor | very good | average |
Merino | good | very good | good | poor |
Tsurcana | average | good | average | average |
A farmer wants to sell both meat and wool.
Suggest which breed of sheep in Table 1 is the most suitable for this farmer.
Give a reason for your choice.
4 marksAnother farmer wants to produce a new breed of sheep with both a very good milk yield and a very good quality of wool.
The farmer is able to buy any of the breeds of sheep shown in Table 1.
Describe the process this farmer would use to produce the new breed of sheep on her farm.
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1 markAn ecologist studied variation in a species of xerophyte.
Xerophytes are adapted to a particular type of environment.
State this type of environment.
3 marksThe ecologist studied the features of the leaves in the species of xerophyte.
Fig. 1 shows the variation in the type of leaf spike.
Fig. 1
(i)
State the type of variation shown in Fig. 1.
[1]
(ii)
Explain why the type of leaf spike is an example of the variation shown in Fig. 1.
[2]
2 marksThe ecologist also measured other features of the leaves.
Fig. 2 shows the variation in leaf feature B.
Fig. 2
State two named features of leaves that show the type of variation shown in Fig. 2.
1 markAfter one year, the ecologist recorded the variation in leaf feature B again.
The results are shown in Fig. 3.
Fig. 3
Suggest one reason for the difference in variation of leaf feature B after one year.
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2 marksAll commercial breeds of sheep belong to the species Ovis aries.
Define the term species.
2 marksThe Merino is a breed of sheep that is farmed mainly for its wool. The wool is very thick and is made of lots of very thin hairs.
Fig. 1 shows a female Merino sheep with her newborn lamb.
Fig. 1
The presence of hair is a feature that is only found in mammals.
State two other features that distinguish mammals from all other vertebrates.
5 marksMerino sheep in South Africa have high quality wool with very thin hairs.
Breeders in New Zealand have used selective breeding programmes to improve the wool of their sheep to match the quality of South African wool.
Describe the steps that breeders would take to breed sheep that have wool with very thin hairs.
3 marksExplain how natural selection differs from selective breeding.
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1 markBlood group is an example of discontinuous variation.
The blood groups of patients in a hospital were recorded.
Fig. 1 shows the results.
Fig. 1
Explain how Fig. 1 shows that blood group is an example of discontinuous variation.
2 marksTable 1 shows different examples of variation.
Tick all the boxes that show examples of discontinuous variation.
Table 1
Attached or unattached earlobes |
|
Foot length |
|
Height |
|
Tongue rolling |
|
Weight |
|
3 marksVariation can be caused by mutation.
The word mutation can be connected to the words in the boxes on the right to make a complete sentence.
Draw three lines to join the word ‘mutation’ to the words in the boxes to make three correct sentences.
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2 marksCoat colour in horses is controlled by genes.
The allele for black coat (E) is dominant.
The allele for red coat (e) is recessive.
Place ticks in the table to show the coat colours of horses with each of the following genotypes.
genotype | black coat | red coat |
EE |
|
|
Ee |
|
|
ee |
|
|
1 markModern horse breeds look very different to each other, but still belong to the same species.
Fig. 1 shows three different horse breeds.
Fig. 1
State the term used to describe the difference between individuals of the same species.
3 marksShire horses have been produced by selective breeding. They are strong and can pull heavy loads.
Describe the process of selective breeding.
2 marksDescribe how natural selection differs from selective breeding.
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3 marksCompare natural selection with artificial selection.
4 marksSelective breeding is an example of artificial selection.
The Wild Mustard plant has undergone extensive selective breeding for hundreds of years.
Fig. 1 shows the outcome of this selective breeding and the traits that have been selected for.
Fig. 1
Outline how selective breeding of the Wild Mustard plant has led to the development of the Kale plant.
4 marksStreptomycin is an antibiotic.
Table 1 shows results scientists collected from a study examining the effect of streptomycin on a bacterial population over fifteen generations.
The bacterial population consisted of organisms of two variants (X and Y).
Table 1
generation | frequency of variant X in the population | frequency of variant Y in the population |
1 | 52 | 51 |
2 | 55 | 49 |
3 | 64 | 44 |
4 | 66 | 41 |
5 | 73 | 38 |
6 | 76 | 32 |
7 | 81 | 26 |
8 | 85 | 21 |
9 | 89 | 16 |
10 | 94 | 12 |
11 | 98 | 8 |
12 | 99 | 5 |
13 | 99 | 2 |
14 | 99 | 1 |
15 | 99 | 1 |
Describe and explain the data shown in Table 1.
4 marksExplain the process that has led to the results shown by variant X in Table 1.
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2 marksFig. 1 shows a micrograph of a leaf from a desert plant.
Fig. 1
Identify and label two adaptive features visible in Fig. 1.
2 marksFor one of the features identified in part (a), explain how this is an adaption for the plant.
2 marksFig. 2 shows a micrograph of a leaf from a different type of plant.
Fig. 2
Suggest and explain what type of plant this leaf may be from.
6 marksA student investigated the submergence of leaves from plants in a pond and the depth of the roots within sediment.
Table 1 shows their results.
Table 1
submergence of leaf within pond | depth of roots within sediment / cm |
floating | 58 |
partially submerged | 35 |
fully submerged | 23 |
(i)
Explain which type of data is shown by the depth of roots within the sediment.
[2]
(ii)
Explain which type of graph would best display this data.
[2]
(iii)
Suggest a conclusion for the data.
[2]
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5 marksScientists investigated mutations in ants by exposing them to UV rays. Their results are shown in Fig. 1.
Fig. 1
(i)
Explain why is meant by a mutation.
[1]
(ii)
Describe and explain the results in Fig. 1.
[2]
(iii)
Calculate the percentage change in mutations from the first dose of UV radiation to the last.
[2]
2 marksExplain whether all mutations are harmful or not.
3 marksFig. 2 shows an ant.
Fig. 2
Use the information in Fig. 2 to determine the kingdom, phylum and class of ants.
4 marksThere are more than 12 000 known species of ants. Fig. 3 shows a fossilised ant that was embedded in amber about 20 million years ago.
The physical form of ants has barely changed throughout their history.
Fig. 3
Image courtesy of Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Extinct_fungus-growing_ant_(23411374650).jpg
Insects Unlocked, CC0, via Wikimedia Commons
Suggest an explanation for what this tells you about the adaptive features of ants.
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