Organisms and their environment

1
INTERACTIVE MULTIPLE CHOICE QUESTIONS
Organisms and their environment
The answers are provided. Explanations of why the
alternatives are unsatisfactory are also offered
2
These multiple choice questions are similar to
the ones set by the GCSE and IGCSE Examination
Boards except that, in some cases, there may be
more than one acceptable answer
For this reason, even if you select a correct
answer at your first attempt, it is worth looking
at all the alternatives (a)
to see if there is a better answer and
(b) to see
why some of the alternatives are unacceptable
Question 1
3
Question 1
A thrush, a snail, a cabbage and a sparrow hawk
are all part of a food chain. Which of them is a
primary (or first order) consumer?
(a) The cabbage
(b) The snail
(c) The sparrow hawk
(d) The thrush
Question 2
4
No
The cabbage is the producer at the beginning of
the food chain
5
Yes
The snail is the primary (first order) consumer.
It eats the cabbage leaves
6
No
The sparrow hawk is a tertiary (third order)
consumer at the end of the food chain. It is a
predator of the thrush
7
No
The thrush is the secondary (second order)
consumer. It eats the snail and is itself eaten
by the sparrow hawk
8
Question 2
In the nitrogen cycle, the bacteria in root
nodules of leguminous plants can convert
atmospheric nitrogen into nitrates. These
bacteria are called
(a) nitrifying bacteria
(b) denitrifying bacteria
(c) nitrite bacteria
(d) nitrogen-fixing bacteria
Question 3
9
No
Although the bacteria in root nodules ultimately
increase the nitrogen content of the soil, the
term nitrifying bacteria applies mainly to
bacteria living freely in the soil. These
bacteria cannot use atmospheric nitrogen.
10
No
Denitrifying bacteria convert the nitrates in the
soil into atmospheric nitrogen.
11
No
Nitrite bacteria live freely in the soil and
convert ammonium ions into nitrates. They cannot
use atmospheric nitrogen
12
Yes
The nitrogen-fixing bacteria (Rhizobium spp) live
mainly in root nodules of leguminous plants. They
convert nitrogen (from the air in the soil) into
nitrates, which are eventually incorporated into
amino acids by the plant.
13
Question 3
sunlight
CONSUMERS
die
The diagram represents a natural recycling process
eaten
die
A
PRODUCERS
minerals and salts
What is missing at A?
decay
(a) Animals
SOIL
(b) Plants
(c) Decomposers
(d) Bacteria
Question 4
14
No
Animals are the consumers
15
No
Plants are the producers
16
Yes
The decomposers, (mainly bacteria and fungi)
break down the dead remains of organisms and
release their products into the soil
17
No
Some bacteria are important decomposers, but
there are many species of bacteria which are not
decomposers. Also, there are many fungi which
play a part in decay.
18
Question 4
In a food chain, the amount of energy passed from
one trophic level to the next .
(a) increases
(b) decreases
(c) stays the same
(d) sometimes increases sometimes decreases
Question 5
19
No
The organisms at any trophic level will be using
part of their resources to produce energy, so
there will be less to pass to the next level
20
Yes
The organisms at any trophic level will be using
part of their resources to produce energy, so
there will be less to pass to the next level
21
No
The organisms at any trophic level will be using
part of their resources to produce energy, so
there will be less to pass to the next level
22
No
The amount of energy passed from one trophic
level to the next may vary but there is always a
decrease
23
Question 5
C
population
The graph shows the sigmoid curve for population
growth.
At C
B
(a) the death rate exceeds the reproduction rate
(b) the reproduction rate exceeds the death rate
A
(c) the death rate and repro-duction rates are
the same
time
(d) the death rate and repro-duction rate
decrease equally
Question 6
24
No
If the death rate exceeds the reproduction rate,
the population will decrease
25
No
If the reproduction rate exceeds the death rate,
the population will continue to grow
26
Yes
If organisms die at the same rate as they are
created, the population will be stable
27
Yes
If fewer organisms are created, but the death
rate decreases at the same rate, the population
will stay the same but the point of stability
will be reached at a lower population level
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Question 6
What is the source of energy on which nearly all
living organisms ultimately depend?
(a) Photosynthesis
(b) Respiration
(c) Combustion
(d) Sunlight
Question 7
29
No
Nearly all living organisms depend directly or
indirectly on photosynthesis by plants for their
energy supply. But this is not the ultimate
source of energy
30
No
Respiration is the way in which most living
organisms derive energy from their food but it is
not the ultimate source of energy
31
No
Combustion is a source of energy for many
processes but not for living organisms
32
Yes
The process of photosynthesis in green plants
uses energy from sunlight for making food. The
energy from this food is used by nearly all
living organisms either by eating plants or
eating each other
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Question 7
Which of the following gases are the cause of
acid rain?
(a) Carbon dioxide
(b) Carbon monoxide
(c) Nitrogen oxide
(d) Sulphur dioxide
Question 8
34
No
Carbon dioxide does dissolve in rain to form a
weak solution of carbonic acid (H2CO3) but this
is normal and does not contribute to what is
known as acid rain. However, it is thought to
be making the ocean more acid and this is a cause
for concern
35
No
Carbon monoxide is a poisonous gas but does not
contribute to acid rain
36
Yes
Oxides of nitrogen dissolve in rain water to form
nitric acid which is very harmful to lakes and
land plants
37
Yes
Sulphur dioxide dissolves in water to form,
eventually, sulphuric acid. This damages lakes
and land plants
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Question 8
Acute shortage of oxygen in lakes and rivers is
caused by
(a) eutrophication
(b) the oxygen demand by the excess of decaying
plant material
(c) excess nitrate and phosphate
(d) excessive growth of algae
Question 9
39
No
Eutrophication refers to a high level of
nutrients in a body of water. It may cause
excessive algal growth but is not a direct cause
of oxygen depletion
40
Yes
The oxygen demand of an excess of decomposing
plant material, e.g. algae, is the immediate
cause of the reduction in the oxygen content of
the water in lakes and rivers. The excess of
plant material is the result of eutrophication

41
No
Eutrophication results from high levels of
nitrate and phosphate in the water. But although
this encourages excessive algal growth it does
not inevitably lead to oxygen depletion.
42
No
The excessive growth of algae is not itself a
cause of oxygen depletion.
43
Question 9
Which of the following processes make no net
contribution of carbon dioxide to the Earths
atmosphere?
(a) Growing crops
(b) Burning wood
(c) Burning coal
(d) Raising cattle
Question 10
44
Yes
The growing crops are photosynthesising and
removing carbon dioxide from the atmosphere.
45
Yes
The carbon in wood comes from the carbon dioxide
absorbed by the tree in the course of
photosynthesis. When the wood is burned, the
amount of carbon dioxide released is the same as
that taken in by photosynthesis
46
No
The carbon in coal comes from trees which were
fossilized about 300 million years ago. So the
carbon dioxide released from burning coal adds to
the present day carbon dioxide in the atmosphere
47
No
Respiration in cattle produces carbon dioxide
which is added to the atmosphere
48
Question 10
For the conservation of animals, the most
important step is
(a) reduction in the use of pesticides
(b) preservation of habitat
(c) suppression of hunting
(d) captive breeding programmes
49
No
Reduction in the use of pesticides certainly
helps to conserve, for example, insect species
and the organisms which feed on them (e.g. birds)
but it affects only a limited range of animals
50
Yes
This is the most important step. If an animals
habitat is destroyed, it is unlikely to survive
51
No
Suppression of hunting helps to conserve a number
of species, such as the rhinoceros, but many
animal populations are not threatened by hunting
52
No
Captive breeding may help conserve animals
threatened with extinction but if their habitat
has been destroyed they cannot usually be released
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