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Multiple-choice
1.
The figure below shows an evolution process.
Evolution
First amphibian
First reptile
When the first amphibian evolved to become the first reptile, which of the following characters was gained?
A.
homoiothermic temperature control
B.
breathing with lungs
C.
internal fertilisation
D.
carnivorous diet
□
2.
During the formation of fossils, the chemical substances in the bones of dead organisms are replaced by
A.
vitamins.
B.
minerals.
C.
fossil fuel.
D.
rock.
□
3.
Which of the following statements is/are correct?
(1)
(2)
Fossil records provide us with information on the life forms which once existed on the Earth.
The more similar the DNA compositions of two organisms are, the closer their evolutionary relationship is.
(3)
Evolution of organisms can take millions of years.
A.
(1) only
B.
(1) and (2) only
C.
(2) and (3) only
D.
(1), (2) and (3)
□
4.
Which of the following cannot be determined from the fossil records?
A.
how the organisms live in the past
B.
the history of the life on Earth
C.
the age of the Earth
D.
the time that a species become extinct
□
5.
Which of the following statements about evolution is correct?
A.
Evolution does not occur in humans.
B.
Organisms will not undergo evolution nowadays.
C.
Complex organisms nowadays evolve from simple ones.
D.
No evolution is possible if there is mutation.
□
6.
Which of the following statements about fossils is/are correct?
(1)
They are mostly found in sedimentary rock.
(2)
The fossils that are present in the lower rock layers are earlier than those present in upper rock layers.
(3)
Fossils embedded in the rocks are the only clue to reveal the various forms of life in the past.
A.
(2) only
B.
(1) and (2) only
C.
(1) and (3) only
D.
(1), (2) and (3)
□
7.
The following picture shows the fossil of Archaeopteryx.
The organism shown above possessed teeth, a long tail, and wings with feathers. Which of the following existing
organisms resemble(s) the organism in the picture?
(1)
mammal
(2)
bird
(3)
reptile
A.
(2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
□
Directions: Questions 8 to 10 refer to the diagram below which shows some of the changes in horses that have occurred over the
past 60 million years. The numbers on the foot bones represent different toes. Those horses below the Present day
are extinct.
Present day
Modern horse (Equus)
1.6 m
3
Pliocene era
(10 million years ago)
Pliohippus
1.25 m
3
Miocene era
(30 million years ago)
Merychippus
1.0 m
2
4
3
Oligocene era
5
(40 million years ago)
Mesohippus
0.6 m
2
Hyracotherium
0.4 m
2
3
4
Eocene era
(60 million years ago)
8.
3
5
4
Which of the following statements is correct?
A.
Pliohippus was four times as tall as Hyracotherium.
B.
Mesohippus had fewer toes than Hyracotherium.
C.
The fifth toe was lost in the Miocene era.
D.
The greatest reduction in the size of the second and fourth toes occurred in the Oligocene era.
□
9.
What was the advantage to the change in the length of the foot bones over the 60 million years?
A. The length of the leg was reduced so that the mass of the horse was spread evenly.
B. The horse could balance on its third toe.
C. It could bring the second and fourth toes in line with each other.
D. The length of the leg was increased so that the horse can run faster.
□
10.
Hyracotherium is now extinct. Which of the following is not the possible cause for its extinction?
A.
fossilisation
B.
occurrence of new predators
C.
a change in the environment
D.
a mutation in pathogens
□
Directions: Questions 11 to 14 refer to the following diagrams.
The limbs of animals have changed during the course of evolution.
Diagram I shows an ancestral limb plan for the forelimbs of all vertebrates.
upper arm (humerus)
forearm (radius + ulna)
wrist (carpals)
hand / foot
(metacarpals
+ phalanges)
1
2 3 4 5
Remark:
- Metacarpals mean the
bones of the palm.
- Phalanges mean the
bones of fingers.
Diagram I
Diagram II shows the arrangement of the bones in the forelimbs of three mammals: a monkey, a horse and a dolphin.
5
carpals
1
carpals
5
1 34
2
Monkey’s forelimb
4
3
2
3
Horse’s forelimb
Dolphin’s forelimb
Diagram II
11. What does the arrangement of the limb bones in the three mammals indicate about their evolutionary relationship?
A.
The bones remain almost in the same position in all vertebrates.
B.
Mammals share a common ancestor with other vertebrates.
C.
They have adapted themselves to different forms of movement.
D.
Evolution has caused the bones to change shape and arrangement in different mammals.
□
12. Which of the following processes causes changes in the limb structure of vertebrates?
A.
competition
B.
mutation
C.
natural selection
D.
variation
□
13. The bones of the front flippers of the dolphin are adapted for
A.
bearing the weight of the animal.
B.
defending itself against predators.
C.
increasing surface area of flipper for swimming.
D.
supporting a large surface area of body tissue.
□
14.
Which of the following is not the difference between monkey’s forelimb and horse’s forelimb?
Monkey
Horse
A.
It has five digits.
It has one digit.
B.
Ulna does not fuse to radius.
Ulna fuses to radius.
C.
It is adapted for grasping.
It is adapted for running.
D.
It has metacarpals.
It has no metacarpals.
□
15.
The effectiveness of DDT against mosquitoes was found to be decreasing over the decades.
This is not the result of
A.
gene mutation.
B.
natural selection.
C.
speciation.
D.
gene inheritance.
□
16.
Which of the following organisms does not have camouflage developed during evolution?
A.
panda
B.
tiger
C.
grasshopper
D.
chameleon
□
17.
Which of the following studies illustrate(s) natural selection?
(1)
study of the peppered moths
(2)
study of Darwin’s finches
(3)
study of fossils
A.
(1) only
B.
(1) and (2) only
C.
(1) and (3) only
D.
(2) and (3) only
□
18.
Which of the following characteristics that the modern giraffes inherited from their ancestors enable(s) them to have
a greater chance of survival?
(1)
a long neck to feed on tree leaves
(2)
special teeth to chew leaves
(3)
a sharp vision to find food
A.
(1) only
B.
(3) only
C.
(1) and (2) only
D.
(2) and (3) only
□
19.
Which of the following is not the result of evolution?
A.
camouflage in peppered moth
B.
adapted beaks in finch
C.
long neck in giraffe
D.
formation of fossils
□
20.
The theory of natural selection proposed by Charles Darwin suggests that
(1)
genetic variations exist among individuals of the same species such that some individuals are better adapted to the
environment than others.
(2)
organisms which are better adapted to the environment are able to survive and more likely to reproduce, passing
their characteristics to the next generation.
(3)
overproduction of the young and limited resources cause competition within the species.
A.
(2) only
B.
(1) and (2) only
C.
(2) and (3) only
D.
(1), (2) and (3)
□
21.
Natural selection allows the survival of
(1)
the strongest.
(2)
the largest.
(3)
the fittest.
A.
(3) only
B.
(1) and (2) only
C.
(1) and (3) only
D.
(1), (2) and (3)
□
Directions: Questions 22 and 23 refer to the following passage.
Peppered moths exist in two colour forms: light and dark. In the past, those moths were mostly
in the light form in Britain, as the tree trunks, which were covered with light-coloured lichens,
offered them protection against birds which were their predators. Some years later, as a result of the
Industrial Revolution, the lichens were killed by pollutants and the surfaces of tree trunks became
black. Consequently, the light moths became conspicuous and were easily seen by birds. Thus, they
were preyed upon and their number decreased. The dark moths, however, were more able to survive
in the blackened background. More dark moths could then reproduce and pass on their
characteristics to the next generation. Soon, there were more dark moths than the light ones.
22. What kind of protection was offered to the moths by the tree trunks?
23.
A.
filtering of ultra-violet light
B.
prevention of desiccation
C.
camouflage
D.
provision of cooling effect
□
Based on the theory of natural selection, which of the following statements about the peppered moths in the above
passage is/are correct?
(1)
Genetic variation existed in this species.
(2)
Peppered moths with advantageous characteristics were selected by the environment.
(3)
Natural selection of the moths in this case was carried out in the form of hunting by the birds.
A.
(3) only
B.
(1) and (2) only
C.
(1) and (3) only
D.
(1), (2) and (3)
□
24.
Nowadays some antibiotics are ineffective in combating against some bacteria. Which of the following statements
is/are correct?
(1)
Some bacteria in a population acquire antibiotic-resistant genes.
(2)
Bacteria having the antibiotic-resistant genes can survive and pass on the genes to their offspring.
(3)
Bacteria have fast reproductive rate in which the population is quickly replenished.
A.
(2) only
B.
(1) and (2) only
C.
(1) and (3) only
D.
(1), (2) and (3)
□
25.
A new species of organism is considered to have evolved when its population
A.
is isolated from the rest of the population by a geographical barrier.
B.
shows increased variation due to mutations.
C.
can no longer interbreed successfully with the rest of the population.
D.
is subjected to increased competition in its habitat with limited resources.
□
26.
Charles Darwin proposed his theory of evolution in 1859. Other theories at the time included Lamarck’s theory. Lamarck’s
theory stated that organisms inherited characteristics that had been developed during the lifetime of their parents. Darwin’s
and Lamarck’s theories are similar in that they both
A.
stated that evolution happened very rapidly.
B.
stated that evolution depended on changes in the environment.
C.
relied on the condition that parents were able to alter the characteristics of their offspring.
D.
depended on information about the characteristics of organisms being passed from parents to offspring.
□
Directions: Questions 27 to 29 refer to the graph below which shows the changes in the populations of light peppered moths and
dark peppered moths in a wood in England from 1840 to 1880.
From 1840 onwards, the colour of the tree bark changed from light grey-green to black as a result of air pollution
which was caused by Industrial Revolution.
300
250
200
Number of
moths
150
100
50
0
1840
Key:
1850
1860
Year
1870
Light moth
1880
Dark moth
27. What was the proportion of light moths in the wood in 1865?
A.
0.02
B.
0.1
C.
0.3
D.
0.5
□
28. What conclusion can be drawn from the graph?
A.
B.
The number of dark moths was directly proportional to time.
The rate of increase in the dark moth population was approximately equal to the rate of decrease in the light moth
population.
C.
The peppered moth population would be eliminated by 1890.
D.
Air pollution was the direct cause of the decrease in the light moth population.
□
29.
The Clean Air Act was passed in 1950. This resulted in a large decrease in air pollution.
Which of the following is a likely reason for the change in the numbers of light and dark moths in the 50 years after the
Clean Air Act?
A.
The colour of the tree bark changed so that the light moth was less readily seen by birds.
B.
Light moths were killed by a new disease.
C.
Dark moths moved into the wood from other areas.
D.
Pollution in the air changed the colour of the moths.
□
30.
Which of the following are examples of reproductive isolation?
(1)
differences in the mating season between two species of toads
(2)
inability to form pollen tubes when pollen grains from a different species land on the stigma
(3)
variation in the shape of penises of different species of damselflies
A.
(1) and (2) only
B.
(1) and (3) only
C.
(2) and (3) only
D.
(1), (2) and (3)
□
31.
The following table shows the amino acid sequence of part of the insulin polypeptide chain in different organisms.
(Each letter represents one kind of amino acid)
Organisms
Amino acid sequence
Human
R
R
E
A
E
D
L
Q
V
G
Q
V
E
L
G
G
G
Guinea pig
R
R
E
L
E
D
P
Q
V
E
Q
T
E
L
G
M
G
Pig
R
R
E
A
E
N
P
Q
A
G
A
V
E
L
G
G
G
Cow
R
R
E
V
E
G
P
Q
V
G
A
L
E
L
A
G
G
House mouse
R
R
E
V
E
D
P
Q
V
E
Q
L
E
L
G
G
S
According to the above amino acid sequence, which organism has the closest evolutionary relationship with human?
A.
guinea pig
B.
pig
C.
cow
D.
house mouse
□
32.
By comparing the DNA sequence between organisms, we can determine evolutionary relationships between organisms.
The following shows the DNA sequence of four organisms.
Human:
CCA
TAG
CAC
CTA
Pig:
CCA
TGT
AAA
CGA
Chimpanzee: CCA
TAA
CAC
CTA
Cricket:
AAA
GGG
ACG
CCT
Based on these sequences, which two organisms are most closely related?
A.
human and pig
B.
human and chimpanzee
C.
pig and chimpanzee
D.
pig and cricket
□
Conventional questions
1.
The following photos show three animals: carp, dolphin and gorilla.
 carp
 dolphin
 gorilla
Which two animals are closely related? State two reasons to explain your answer.
(3 marks)
2.
Using peppered moths as example, explain the theory of natural selection.
(6 marks)
3.
Evolution is the process of change in the inherited traits of a population of organisms from one generation to the next. The
basis of evolution is that the genes which are passed on to an organism’s offspring produce the inherited traits. Mutations
in genes can produce new or altered traits in individuals, resulting in the appearance of inheritable differences between
organisms.
(a) State an example of mutagen.
(1 mark)
(b) ‘Mutation is beneficial to organisms.’ Support this statement with the example of finches on the Galapagos Islands.
(5 marks)
4.
Complete the following paragraph with suitable words selected from below.
worse
extinction
cooperation
adverse
favourable
artificial selection
survival of the fittest
struggle for existence
higher
natural selection
perpetuation
speciation
(3 marks)
overcrowding
As organisms generally produce more offspring than the environment can support, there will be a
(a)______________________ due to (b)_________________ and competition among individuals. Only those individuals
with (c)_________________ variations will have a (d)_________________ chance of survival. The result is that
well-adapted individuals can pass these characteristics to their offspring, whereas less well-adapted individuals fail to do
so.
(e)_________________ is the process in which all the individuals of a species die out.
(f)_________________ is the mechanism by which new species arises from pre-existing species.
5.
Read the passage below and answer the questions that follow.
Potato
There are different varieties of the common potato. They are derived from the same
species. Some of the varieties are resistant to bacteria. Some survive under infection by
viruses. Some withstand frost. These varieties contain special genes for developing the
special characteristics. These genes, which are added to a ‘gene bank’, are useful for
potato-breeders to clone the particular potato they need.
(a) Describe the danger of repeated cultivation of crops which are genetically identical.
(2 marks)
(b) Name two factors which can cause variations in a species.
(1 mark)
(c) Name the method of growing new plants from a potato tuber.
(1 mark)
(d) If the varieties advantageous to an organism occur, individuals with these characters will have the best chance to live
and reproduce. Give a term to describe the above statement.
6.
(1 mark)
The following paragraph explains Darwin’s theory of natural selection.
Organisms within a population of the same species show variations, some of which are heritable.
In other words, parents can pass on some of their characteristics to their offspring. Also, organisms
have the ability to increase in numbers but the numbers remain fairly constant over time due to
limited resources. The result is that some individuals produce more offspring which possess their
successful characteristics than others, and these offspring can in turn pass on these characteristics to
future generations.
The consequence of natural selection is that the characteristics change from generation to
generation in a population, and organisms tend to become better adapted to the ever-changing
environment.
(a) State two causes of variation.
(2 marks)
(b) Explain why limited resources cause the numbers of organisms to remain constant.
(1 mark)
(c) Suggest two examples in which organisms get adapted to a particular environment.
(2 marks)
7.
The diagram below shows a simplified version of how some of the organisms evolved from single cells.
B
A
Kingdom 1
Kingdom 2
unicellular prokaryote
(a) Name kingdoms 1 and 2.
(2 marks)
(b) Organisms A and B can form seeds, but their reproductive structures are different. State their respective
reproductive structures.
(2 marks)
(c) Scientists study fossil records of organisms in order to understand evolution.
(i)
How were fossils formed?
(3 marks)
(ii)
Give two reasons to explain why there were gaps in fossil records.
(2 marks)
8.
The following diagram shows a time scale and the skull of a modern human, Homo sapiens, together with those of some
possible ancestors.
Homo
sapiens
Homo
erectus
Homo
habilis
Australopithecus
afarensis
brow
ridge
1
2
3
cranium
4
5
millions years ago
(a) State how the skull fossil can be formed.
(3 marks)
(b) State two structural differences between the skull of Australopithecus afarensis and Homo sapiens.
(2 marks)
(c) State one piece of fossil evidence that might indicate whether a human ancestral species could walk with two legs.
(1 mark)
(d) (i)
(ii)
Besides fossil record, state another evidence of human evolution.
(1 mark)
What is the limitation of this evidence?
(1 mark)
(e) Give one disadvantage of the use of fossils in providing evidence for human evolution.
(1 mark)
9.
In an exhibition, Edward has a chance to look at the fossils of an extinct bird.
The fossils are sources of evidence to prove that life has evolved from simple ancestors.
(a) Describe the formation of a fossil.
(2 marks)
(b) What method do scientists use to determine the age of a fossil?
(1 mark)
(c) Explain why fossils can be used as the evidence of evolution.
(3 marks)
(d) State two important concepts in Darwin’s theory of evolution.
(2 marks)
The following graph shows the cyclic changes in the populations of a kind of black insect and a kind of bird in a garden
with many evergreen trees.
insect
bird
Population size
10.
Time
(a) Name the ecological relationship between the two groups of animals.
(1 mark)
(b) With reference to the graph, state and explain the change in the number of birds when the number of insects
decreases.
(2 marks)
(c) Some of the insects have developed green body colour.
(i)
State and explain one advantage to develop this colour.
(ii)
Explain how natural selection occurs on this kind of insect with reference to their body colours.
(3 marks)
(4 marks)
11.
The following short paragraph is about evolution.
Mutations, the factors for evolution, are said to be random as they can be beneficial, harmful
or neutral to organisms. However, the action of natural selection on mutations is non-random
because only the beneficial ones are selected and preserved by the environment.
(a) What is mutation?
(1 mark)
(b) State one example for both spontaneous and induced mutations.
(2 marks)
(c) Explain how beneficial mutated characters in animals can be passed on from generation to generation in the course
of evolution.
(2 marks)
(d) Harmful mutations may weaken or kill an organism by affecting its metabolic activities. Explain.
12.
(3 marks)
One variety of the peppered moth, Biston betularia, has pale, speckled wings. A second variety of the same species has
black wings. The figure below shows the peppered moths in a rural area.
(a) A study was carried out in 1850’s. The numbers of the two peppered moth varieties were investigated in Area A
(a rural area) and in Area B (an industrial area). The table below shows the average number per tree.
Number of black moths
Number of pale moths
Area A
0
95
Area B
85
10
At that time, many lichens on the tree bark in the industrial city had been killed by industrial pollution. The tree bark
and other surfaces were often blackened by soot. The area studied in the rural area was free of industrial pollution.
Explain how the process of natural selection might have led to the different number of the varieties of the peppered
moth seen in the two areas.
(5 marks)
(b) The colour of peppered moth is controlled by a pair of alleles. The black wings are the result of dominant allele W
and pale wings are the result of recessive allele w.
Using a genetic diagram, state the proportion of pale moths produced from the cross between two heterozygous
black moths.
(3 marks)
(c) Over a very long period of time, it is possible for a variety of one species to develop into a separate species. Suggest
how this could happen in peppered moth.
(3 marks)
13.
The following diagram shows the Hawaiian Islands which are 3000 km from the nearest continent. The islands were
formed relatively recently from volcanic activity. Due to high mountains, local climate varies greatly on each island. 500
species of fruit flies can be found in Hawaii.
(a) Explain how the large number of fruit fly species might have evolved in Hawaiian Islands.
(6 marks)
(b) There are about 22 000 species of insects in Britain but only about 6500 in Hawaii.
Britain however, has 32 species of Drosophila but Hawaii has 500. Suggest an evolutionary explanation for the
difference in the number of species of Drosophila.
(4 marks)
14.
Haemoglobin in mammals is composed of four polypeptide chains: two α chains and two β chains. Table 1 below shows
the sequence of 15 amino acids in an α chain from four different primates: a chimpanzee, a gorilla, a human and an
orang-utan.
Primate
Amino acid sequence
Chimpanzee
K A A WG K V G A H A G E Y G
Gorilla
K A A WG K V G A H A G D Y G
Human
K A A WG K V G A H A G E Y G
Orang-utan
K T A WG K V G A H A G D Y G
Table 1
Key:
A = alanine D = asparagine
E = glutamic acid
G = glycine
K = lysine
V = valine
W = tryptophan Y = tyrosine
T = threonine
H = histidine
(a) What are the differences between the amino acid sequence for the α chain in orang-utan and chimpanzee?
(1 mark)
(b) The amino acid sequences can be compared to determine the evolutionary relationships in the primates.
Using data in Table 1, complete the evolutionary tree diagram below to show the possible evolutionary relationship
between chimpanzee, human, gorilla and orang-utan.
Common
ancestor
(3 marks)
Chimpanzee
(c) State two reasons to explain how the data in Table 1 can support your suggested evolutionary relationship.
(2 marks)
14.
(d) When human blood serum is injected into a rabbit, the rabbit produces antibodies against human serum proteins.
When rabbit serum containing these antibodies is mixed with blood serum from humans and other mammals (e.g.
gibbon, spider monkey and hedgehog), different percentage of coagulation occurs. Table 2 below shows the results.
Mammal
Percentage of coagulation
Human
100
Gibbon
80
Spider monkey
59
Hedgehog
18
Table 2
(i)
What do these data suggest about the evolutionary relationships of the four mammals in Table 2?
(2 marks)
(ii)
15.
Explain why, in this procedure, these differences in percentage of coagulation occur.
(3 marks)
The Isthmus of Panama is a narrow strip of land that separates the Pacific Ocean from the Atlantic Ocean, linking North
and South America. The map below shows the Isthmus of Panama.
Atlantic Ocean
Isthmus of Panama
Pacific Ocean
The photos below show two species of wrasses.
Cortez rainbow wrasse
Blue-headed wrasse
(Thalassoma lucasanum)
(Thalassoma bifasciatum)
The Cortez rainbow wrasse is found in the coral reefs on the Pacific side of the isthmus while the blue-headed wrasse is
found in the coral reefs on the Atlantic side of the isthmus.
It has been found that both species evolved from a common ancestral population that was split as the isthmus formed.
(a) Which genus do the types of wrasse belong to?
(1 mark)
(b) Explain why the Cortez rainbow wrasse and the blue-headed wrasse belong to different species.
(2 marks)
(c) Suggest how DNA analysis can provide evidence that these species have evolved from a common ancestor.
(2 marks)
(d) Explain how the splitting of the common ancestral population into an Atlantic population and a Pacific population
has led to the formation of these two separate species.
16. Write an essay on the following topic.
The evidence for evolution of different mammals
(5 marks)
(11 marks)
Answers
Multiple-choice
Questions No.
Key
Question No.
1.
C
36.
2.
B
37.
3.
D
38.
4.
C
39.
5.
C
40.
6.
B
41.
7.
C
42.
8.
C
43.
9.
D
44.
10.
A
45.
11.
B
46.
12.
B
47.
13.
D
48.
14.
D
49.
15.
C
50.
16.
A
51.
17.
B
52.
18.
A
53.
19.
D
54.
20.
D
55.
21.
A
56.
22.
C
57.
23.
D
58.
24.
B
59.
25.
C
60.
26.
D
61.
27.
D
62.
28.
B
63.
29.
A
64.
30.
D
65.
31.
B
66.
32.
B
67.
33.
68.
34.
69.
35.
70.
Key
Conventional questions
1.
dolphin and gorilla
(1 mark)
Any two of the following reasons: (1 mark each)
(2 marks)
- Dolphin and gorilla have similar skeletal structures (with phalanges, ribs).
- Dolphin and gorilla have the structures that are absent in carp (e.g. mammary glands, lungs, etc.)
- Dolphin and gorilla have greater DNA similarity.
- Dolphin and gorilla belong to the same class (Class Mammalia).
- other reasonable answers
2.
Initially, most moths were light in colour
(1/2 mark)
and most of the tree trunks were covered by light-coloured lichens and mosses.
(1/2 mark)
Therefore, they were well camouflaged from their predators (the birds).
(1 mark)
However, during industrial revolution, the pollutants killed the lichens and mosses.
(1 mark)
The darkened tree trunks could no longer provide protection for the light-coloured moths.
(1 mark)
The light moths were eaten while the dark moths were better adapted to the change.
(1 mark)
These dark moths survived and continued to produce dark moths.
(1 mark)
3.
(a)
tar / ionising radiation / other reasonable answer
(1 mark)
(b)
Darwin suggested that the finches feeding on seeds had first arrived on the Galapagos Islands form the mainland.
(1 mark)
However, there was a lack of seeds for all the finches there,
(1 mark)
only those who possessed modified beaks (result of mutation) which enabled them to feed on other food (e.g. insects)
were able to survive and reproduce.
(1 mark)
The population of those which fed on seeds dropped while those which fed on other food increased.
(1 mark)
Hence the mutation actually helped the finches adapt to the new environment.
(1 mark)
(a)
struggle for existence
(1/2 mark)
(b)
overcrowding
(1/2 mark)
(c)
favourable
(1/2 mark)
(d)
higher
(1/2 mark)
(e)
Extinction
(1/2 mark)
(f)
Speciation
(1/2 mark)
This practice decreases the ability of the crop to adapt to the environmental changes.
(1 mark)
The offspring become more easily attacked by bacteria or viruses, which damage the crop.
(1 mark)
(b)
genes and environment
(1 mark)
(c)
vegetative propagation
(1 mark)
(d)
survival of the fittest
(1 mark)
4.
5.
(a)
6.
(a)
Any two of the following: (1 mark each)
(2 marks)
- meiosis / fertilisation
- mutation
- environment
(b)
It causes competition among organisms which stabilises the population.
(1 mark)
(c)
Any two of the following: (1 mark each)
(2 marks)
- cactus, living in a dry desert, develops spiny leaves to reduce water loss
- colour and shape of leaf insect resembles a leaf to avoid attack by predators
- cheetah develops powerful limb to catch preys
- dark peppered moth is adapted on dark tree trunk to avoid attack by predators
- other reasonable answers
7.
(a)
(b)
(c)
Kingdom 1 – Plantae
(1 mark)
Kingdom 2 – Animalia
(1 mark)
A – Cones
(1 mark)
B – Flowers
(1 mark)
(i) When organisms died, the hard parts such as bones and teeth were not decomposed
(1 mark)
and were covered with sand and mud.
(1 mark)
After many years, the minerals in these parts were replaced by harder minerals,
(1 mark)
which formed the fossils.
(ii) Fossilisation was rare / very few organisms could become fossils.
(1 mark)
Some fossils were still not unearthed / were still in the ground.
(1 mark)
8.
(a)
The head of dead human decayed
(1 mark)
and was covered by sand and gravels.
(1 mark)
Under pressure over millions of year, the bone tissues in the skull were replaced with harder minerals to become fossils.
(1 mark)
(b)
Any two of the following: (1 mark each)
(2 marks)
- The cranial capacity of the skull is larger in Homo sapiens.
- The brow ridge is less prominent in Homo sapiens.
- The face is flatter in Homo sapiens.
(c)
Any one of the following:
(1 mark)
- by observing the fossils of their footprints
- by observing the structure of foot / hip joint / spine
(d)
(e)
(i) analysis of DNA similarity between specimens
(1 mark)
(ii) The DNA samples are incomplete / degraded into pieces.
(1 mark)
The fossil record is incomplete / rare / displaced.
(1 mark)
9.
(a)
(b)
Ancient animal’s bodies were buried in the soil
(1 mark)
Minerals in the bones were replaced by minerals causing them to become fossils.
(1 mark)
Any one of the following:
(1 mark)
- measuring the decay of radioactivity of the rock where it is found
- measuring the depth and position of the fossils in the Earth’s crust.
(c)
The rocks are in strata, the oldest fossils are at the bottom and the most recent are formed at the top.
(1 mark)
The earlier fossils are simpler and present in deeper part
(1 mark)
while the more recent are more complex and are closer to the Earth’s surface.
(1 mark)
This gives some indication of the course of evolution.
(d)
There is a struggle for existence in individuals living in an environment with limited resources.
(1 mark)
The environment only allows the survival of the fittest, the ones that can adapt to the environment and allows them to
reproduce.
(1 mark)
(a)
predation
(1 mark)
(b)
The number of birds also decreases
(1 mark)
because less food is available to birds.
(1 mark)
(i) They can avoid being eaten / have less chance to be eaten
(1 mark)
10.
(c)
when they are masked by the leaves of the trees / camouflaged
(1 mark)
because it is difficult for the predators to recognise them.
(1 mark)
(ii) Due to variation in the body colours, the green insects have a better chance of survival.
(1 mark)
The green insects can survive better to maturity and reproduce,
(1 mark)
transmitting their successful gene for green body to their offspring.
(1 mark)
The environment therefore selects for the green insects and against the black insects.
(1 mark)
11.
(a)
Mutation refers to any sudden change in the genetic materials of an organism.
(1 mark)
(b)
Spontaneous mutation arises from errors in DNA replication / transcription / translation
(1 mark)
Induced mutation is caused by mutagens such as X-rays / gamma rays / ultra-violet rays / other acceptable answers
(1 mark)
(c)
The beneficial mutations help the animals better adapt to the environment / succeed in competing with others for survival.
(1 mark)
The mutated genes are replicated and passed to the next generation
(1 mark)
during reproduction and are therefore inherited.
(d)
The mutations result in the formation of new proteins and / or absence of some proteins
(1 mark)
which can be enzymes or other essential proteins.
(1 mark)
Metabolic activities are controlled by enzymes or these essential proteins.
(1 mark)
12.
(a)
There were variations in the colour of peppered moths originally which were the results of mutation.
(1 mark)
In Area A (rural area), the wood bark was light in colour and this provided camouflage to pale moths,
(1/2 mark)
while black moths were easily spotted by their predators and got eaten.
(1/2 mark)
In Area B (industrial area), the wood bark was blackened by soot and this provided camouflage to black moths,
(1/2 mark)
while pale moths were easily spotted by their predators and got eaten.
(1/2 mark)
In both areas, the adapted variety survived and
(1 mark)
passed on its allele to their offspring, leading to increasing number in the adapted variety.
(1 mark)
(b)
Parents:
Gametes:
F1 generation:
x
Ww
Ww
W
w
W
w
WW
Ww
Ww
ww
pale moth
black moth
3
:
1
Proportion of pale moth = 0.25 or 1/4.
(c)
(2 marks)
(1 mark)
Due to geographical isolation, a variety of peppered moth is separated from another variety by barriers such as mountains
/ oceans. OR
Due to reproductive isolation, a variety of peppered moth displays different courtship behaviours from others / has
mismatch in reproductive organs with others / produces infertile hybrids with others.
(1 mark)
The two varieties are separated and have no chance to interbreed.
(1/2 mark)
Mutation occurs in the population of the variety and the new characteristics are formed and passed on to the next
generations.
(1/2 mark)
Variations are accumulated as a result of natural selection.
(1/2 mark)
Eventually, the two populations of peppered moths can no longer interbreed and become two different species.
(1/2 mark)
13.
(a)
Hawaiian Islands were isolated and formed geographical isolation to populations of fruit flies.
(1 mark)
There was no interbreeding between populations of fruit flies in different islands.
(1 mark)
Different populations of fruit flies occurred in different habitats, and
(1/2 mark)
the environment was only favourable to particular types of fruit flies.
(1/2 mark)
Mutation occurs in the population of fruit flies, resulting in genetic variations.
(1 mark)
Some individuals that are more adapted to the environment could survive and pass their beneficial genes to their offspring.
(1 mark)
After a very long period of time, two groups of fruit flies were unable to produce fertile offspring, becoming two separate
species.
(1 mark)
(b)
British islands are less isolated, compared with Hawaiian island.
(1/2 mark)
There are less geographical isolation and hence fewer colonising species.
(1 mark)
More environments / habitats are available for the fruit flies.
(1/2 mark)
This reduces the competition in the fruit fly populations and most fruit flies are adapted.
(1 mark)
So, less speciation occurs in Britain.
(1 mark)
(or vice versa in Hawaiian islands)
14.
(a)
The 2nd amino acid in the chain of orang-utan is T instead of A and
(1/2 mark)
the 13th amino acid in the chain of orang-utan is D instead of E.
(1/2 mark)
(b)
Orang-utan
Common
ancestor
Chimpanzee
Human
Gorilla
(3 marks)
(c)
Human and chimpanzee have exactly the same sequence in the amino acid, so they must have the closest evolutionary
relationship.
(1 mark)
Gorilla’s differs with human’s by one amino acid (i.e. 13th amino acid) and so it is closer in evolutionary relationship. OR
Orang-utan has the greatest differences (with two amino acid difference) and so its relationship is not as close as that of
(d)
gorilla.
(1 mark)
(i) Gibbon has the closest relationship with human.
(1 mark)
Spider monkey is more distantly related than gibbon and hedgehog is most distantly related.
(1 mark)
(ii) As the rabbit serum contains those antibodies to all human serum proteins, the percentage of coagulation is 100%.
(1 mark)
The closer the evolutionary relationship is, the more proteins are in common, and the higher the percentage of
coagulation is.
(1 mark)
Hedgehog which is most distantly related has fewer proteins in common and hence lowest in the percentage of
coagulation.
(1 mark)
15.
(a)
Thalassoma
(1 mark)
(b)
The two kinds of wrasse have different appearance / characteristics and
(1 mark)
they are unable to interbreed to produce fertile offspring.
(1 mark)
(c)
Through DNA fingerprinting / genome analysis, the DNA sequences of the wrasse species are compared, (1 mark)
similarities in their DNA compositions indicate that they are evolved from a common ancestor.
(d)
(1 mark)
The Atlantic wrasse population and the Pacific wrasse population were geographically separated by the isthmus / strip of
land.
(1 mark)
The two populations were then unable to interbreed.
(1/2 mark)
The environmental conditions are different on the two sides of isthmus, creating different selective pressures on both
sides.
(1 mark)
Wrasses that were adapted to the environment can survive and reproduce, while certain alleles are remained and passed
on to the next generations.
(1 mark)
This led to changes in appearance and behaviours after a long period of time.
(1 mark)
The two populations finally cannot interbreed.
(1/2 mark)
16.
Content (maximum 8 marks)
Contents
Descriptions
Introduction
－ Due to different environmental condition, only the adapted species can
Marks
survive and reproduce.
－ Variation is the basis for natural selection and hence evolution to
(Max. 1 mark)
occur.
Fossil record
－ Fossils of different mammals can be found in different layers of
sedimentary rock.
－ The age of the fossils can be told by measuring its depth / radioactive
dating.
－ The fossils of mammals found in the lower layers are older and less
complex than those discovered in the upper layers.
Comparative
anatomy
(Max. 2 marks)
－ The skeleton of different mammals has different structures,
arrangement and functions.
－ The more similar in the anatomy between different mammals, the more
closely related they may be.
－ Examples include the structure of mammals’ forelimb / skull.
Comparative
embryology
(Max. 2 marks)
－ The embryos of different mammals can be compared to examine their
evolutionary relationship.
－ The more similar the structures of the embryos of different mammals,
the more closely related the mammals are.
Molecular
biology
(Max. 1 mark)
－ The DNA sequences of different mammals can be compared to
examine their evolutionary relationship.
－ The more similar the genetic compositions of two organisms are, the
more closely related the organisms are likely to be.
－ The amino acid sequence of a particular protein (e.g. insulin,
haemoglobin) of different mammals can be compared to examine their
relationship.
－ The more similar the amino acid sequences of two organisms are, the
more closely related the organisms are likely to be.
(Max. 2 marks)