IGCSE
Cambridge (CIE)
Biology
52 mins
5 questions
Theory Questions
Characteristics,
Classification &
Features of
Organisms
Characteristics of Living Organisms / Concept & Uses of Classification Systems /
Concept & Uses of Classification Systems Continued / Features of Organisms /
Features of Organisms Continued
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Total Marks
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1
1 (a)
Extended only
When attempting to classify organisms based on their characteristics, several types of
differences between organisms can be observed. These are shown in Table 1.
Table 1
differences
description
A
Differences observable under a microscope
B
Anatomical differences
C
Differences in DNA base sequences
D
Morphological differences
E
Differences in amino acid sequences
Reorder differences A - E into the order of the amount of detail that can be gained,
starting with the least detailed.
1st
2nd
3rd
4th
5th
(1 mark)
(b)
Extended only
When carrying out DNA base sequence comparisons between species, explain why the
same gene has to be selected from each species for sequencing.
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(2 marks)
(c)
Extended only
Table 2 gives information about the amino acids that go into the chain of haemoglobin
protein found in the blood of various animal species. The second column shows how
many amino acids are different in the haemoglobin of that species to that of humans.
Table 2
animal
number of amino acids different to human haemoglobin
Human
0
Chicken
45
Dog
15
Frog
67
Gibbon
2
Gorilla
1
Grey kangaroo
38
Horse
25
Mouse
27
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3
Humans and gibbons evolved separately from a common ancestor about 18 million
years ago.
Calculate an estimate of how many years ago the evolution of frogs diverged from that of
humans.
Give your answer in standard form.
(3 marks)
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4
2 (a) Classification systems largely depend on grouping species by the features that they
share. All organisms can be classified using a hierarchical system starting with Kingdom
and ending with the Genus and Species.
Suggest the benefits of classifying organisms in a hierarchical system.
(4 marks)
(b)
Extended only
Explain why, in evolutionary terms, the more recent a common ancestor between two
species, the more closely related those two species are.
(2 marks)
(c)
Extended only
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5
Fig. 1 shows the evolution of a group of primates and their associated DNA sequences.
Fig. 1
Using the information provided in Fig. 1 and your knowledge of DNA sequencing as a
means for classification, determine with an explanation, which two primates are most
closely related.
(2 marks)
(d)
Extended only
Explain what Fig. 1 can tell you about the relationship between ancestors of primates.
(2 marks)
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3 (a)
Extended only
Fig. 1 shows a unicellular organism found in freshwater.
Fig.1
Name the Kingdom this organisms belongs to.
[1]
(1 mark)
(b)
Extended only
Explain the features of the organism in Fig. 1 that distinguish it from other organisms.
(2 marks)
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(c) The organism shown in Fig. 1 is found in freshwater and must control its internal
conditions by balancing the amount of water that moves in and out of the cell across the
cell membrane.
(i)
State the process by which water moves in and out of the cell.
[1]
(ii)
As the organism digests its prey, the nutrients released can lower the water potential of
the cell.
Suggest how this might affect the movement of water into or out of the cell.
[2]
(iii)
The cell shown contains a structure called a contractile vacuole, which expels excess
water from the cell. As well as excess water, they also remove waste materials from the
cell.
State the characteristic of living organism that the contractile vacuole carries out.
[1]
(4 marks)
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(d) Fig. 2 shows the same organism from part (a) and it's hunting technique.
Fig. 2
Explain the characteristics of living organisms that would be expressed in this process.
(3 marks)
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9
4 (a) A student investigated the relationship between the wavelength of a light source and
seedling height. The student used strawberry seedlings and grew the plants in an
enclosed box with the coloured light as the only available source of light for the plant.
The student watered each seedling daily with 30ml of water. He grew the seedlings for 3
weeks before taking the final measurement.
Suggest the characteristics of living organisms reflected in this investigation.
(3 marks)
(b) The student grew the strawberry seedlings under different coloured lights. Their results
are shown in Table 1.
Table 1
colour of
initial height of
final height of seedling
growth of seedling /
light
seedling / cm
/ cm
cm
white
14
38
24
blue
15
29
14
red
13
32
19
green
15
21
6
none
14
16
2
(i)
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Explain why the student calculated the growth of seedlings rather than using the final
height.
[2]
(ii)
Calculate the percentage change in the growth of the control group of seedlings. Round
your answer to the nearest whole number.
[2]
(iii)
Explain the need for a control group of seedlings.
[1]
(5 marks)
(c) A gardener also investigated the effect of changing wavelengths of light on the height of
different types of vegetable seedlings. The gardener used an enclosed box and lamps
with different colours of light as the only available light source. The gardener watered
the plants daily from a watering can. The gardener grew five seedlings of each vegetable
over a period of four weeks, measuring their height daily. At the end of the investigation,
these measurements were used to calculate their average height.
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Their results are shown in Fig. 1.
Fig. 1
Suggest with a reason, which light source the gardener should use to produce the tallest
vegetable plants.
(2 marks)
(d) Compare the gardener's experimental method with that of the student's.
(4 marks)
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12
5 (a) Dichotomous keys can be used to identify organisms based on a series of questions
about their features.
Fig. 1 shows a group of leaves.
Fig. 1
Suggest a dichotomous key for the leaves shown in Fig. 1 by completing Table 1. An
example has been done for you.
Table 1
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1
2
statement
answer / instruction
a
leaf is oval shaped
beech
b
leaf is not oval shaped
go to 2
a
b
3
a
b
(3 marks)
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14
(b) Fig. 2 shows a different type of dichotomous key where invertebrates are classified.
Fig. 2
Complete the dichotomous key to show the classification of arthropods into their four
sub groups.
(4 marks)
(c)
Extended only
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15
Fig. 3 shows a range of different plants
Fig. 3
(i)
State whether plants A-C are monocotyledons or dicotyledons.
[3]
(ii)
Identify the type of plant shown in image D and explain your answer.
[2]
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16
(5 marks)
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17