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Questions
Q1.
The peppered moth (Biston betularia) exists in dark and light forms.
(i) Complete the sentence by putting a cross ( ) in the box next to your answer.
Characteristics such as colour are coded for by alleles.
An allele is
(1)
A
B
C
D
a single chromosome
a single gene
an alternative form of the same chromosome
an alternative form of the same gene
(ii) The allele for the dark colour is B and is dominant.
The allele for the light colour is b and is recessive.
Complete the table to show all possible genotypes of dark moths.
(2)
possible genotypes of dark moths
(iii) Complete the Punnett square for a cross between a moth heterozygous for colour and a moth
homozygous recessive for light colour.
(2)
(iv) Give the ratio of light to dark moths in the Punnett square in (a)(iii).
(1)
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Q2.
The graph shows the body temperature of 60 people.
(i) Complete the sentence by putting a cross (
The range in body temperature is
) in the box next to your answer.
(1)
A 0.1
B 1.1
C 11.0
D 11.1
(ii) State the type of variation, shown in the graph, that results in a normal distribution curve.
(1)
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(iii) Calculate the percentage of people with a body temperature of 37.5 °C.
(2)
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Q3.
The graph shows the variation in height.
(i) Complete the sentence by putting a cross (
The range in heights of the students is due to
) in the box next to your answer.
(1)
A environmental influences only
B genetic influences only
C environmental and genetic influences
D neither environmental nor genetic influences
(ii) Describe the variation in height of these students, as shown in the graph.
(3)
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Q4.
Cystic fibrosis (CF) is a recessive genetic disorder.
The recessive allele is shown as f and the dominant allele as F.
The family pedigree shows the inheritance of cystic fibrosis (CF).
Both parents are heterozygous for CF.
(i) State what is meant by the term heterozygous.
(1)
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(ii) Explain why Rebecca does not have CF.
(2)
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Q5.
Charles Darwin studied the variety of finches on the Galapagos Islands.
He used this information to develop his theory of evolution.
Some of the finches are shown in the diagram.
Suggest how these species of finches could have evolved.
(3)
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Mark Scheme
Q1.
Question
Number
(i)
Answer
Acceptable answers
(1)
D
Question
Number
Answer
(ii)
Acceptable answers
Accept any two of
the genotypes in any
order
Question
Number
Mark
Answer
Mark
(2)
Acceptable answers
Mark
(iii)
1 mark for correct
parental gametes 1
mark for correct
offspring
Question
Number
(iv)
Answer
(2)
Acceptable answers
Mark
2:2
e.c.f
(1)
Answer
Acceptable
answers
Mark
Q2.
(i)
(ii)
(iii)
B – 1.1
continuous (data /
variation)
18
⁄60 (1) 0.3 × 100 =
30(%) (1) Or 0.33 ×
100 = 33(%) (1)
(1)
(1)
correct answer 2
marks
(2)
Q3.
Question
Number
(i)
Question
Number
(ii)
Answer
Acceptable answers
Mark
C
Answer
Acceptable answers
(1)
Mark
A description
including the
following points:
• continuous
variation / data (1)
• normal distribution
curve (1) • correct
interpretation of data
from the graph (1)
bell shaped curve
e.g most common
height range 150 –
154
(3)
Q4.
Answer
Acceptable
answers
(i)
an individual who
has one recessive
allele and one
dominant allele (1)
(ii)
An explanation to include two of the
following:
 Rebecca is homozygous dominant(for
CF)(1)
 Rebecca has (inherited) one dominant
allele from each parent(1)
 cystic fibrosis involves the inheritance of
two recessive alleles (1)
Mark
(1)
2 different alleles
Rebecca has (inherited) 2 dominant
alleles
(2)
Q5.
Answer
Acceptable
answers
Mark
A suggestion linking three of the following points:
 variation between species/ beak sizes/ shapes (1)
 due to mutation(1)
 competition for resources (1)
 survival of the fittest /those best adapted to the environment survived (1)
 those who survive pass their genes/characteristics onto their offspring (1)
 natural selection (1)
(3)