Past Questions and Answers on Ecology
SSCE/WASSCE/GCE PASS QUESTIONS AND ANSWERS
OBJECTIVES
1.
Which of the following best
describes the biosphere?
A. The non-living
parts of an environment
B. all ecosystems
and the organisms which inhabit them
C. All living
parts of an ecosystem
D. All the members
of a single species in a habitat
2.
The earthworm can be
classified as
A.
decomposer
B.
producer
C. primary consumer
D. secondary consumer
3.
Mutualism is exhibited by
A.
tapeworm living in the gut of
man
B.
yellow dodder growing on milk
bush
C.
platycerium growing on palm
tree
D.
rhizobium living in the root
nodules of groundnut
4.
Food webs are complex
because
A.
the number of producers is
large
B.
many animals feed directly on
them
C.
they include primary, secondary
and tertiary consumers
D.
some animals form part of the
several food chains
5. Which of the following
group of organisms is made up of consumers?
A.
goat, dog, flea
B.
grass, cassava, maize
C.
maize, mouse, eagle
D.
cassava, lion, dog
6. The instrument used to
determine pressure is
A.
anemometer
B.
barometer
C. hygrometer
D. hydrometer
7. In fresh water habitat, the
ecological factor which least affects organisms is
A.
oxygen content
B.
temperature
C. turbidity
D. wind
8.
The ecological role of an
organism in a habitat can be referred to as its
A.
biome
B.
ecosystem
C. micro-habitat
D. niche
9. the consumer in an
ecosystem are usually
A.
carnivores
B.
decomposers
C. herbivores
D. omnivores
10.
light intensity is measured with a/an
A.
barometer
B.
thermometer
C. photometer
D. anemometer
11. In an ecosystem, the LEAST efficient energy
transfer link is from
A. producers to
primary consumers
B. sun to
producers
C. primary
consumers to secondary consumers
D. secondary
consumers to decomposers
12.
Lichen is an example of
A. saprophytic
organism
B. a symbiotic
association
C. an epiphytic
plant
D. a carnivorous
plant
13. The salinity of a brackish environment
A. increases immediately after rain
B. increase at the end of rainy season
C. Decrease with increase in micro-organisms
D. increase during dry season
14. What do bacteria in root nodules derive from the host plant?
A. Protection and minerals
B. Water and minerals
C. Carbohydrates and water
D. Protection and carbohydrates
15.
The most important factors
which influence an organism's way of life in its habitat are
A. the physicals
and biotic environment
B. Food and water availability
C. temperature, water, light and
predator-prey relationship
D. competition for food and spaces
16. Organisms in an ecosystem are usually grouped according to their
trophic level as
A. carnivores and epiphytes
B. consumers and parasites
C. producers and consumers
D. producers and saprophytes
17. A food web is more stable than a food chain because
A. it contains more organisms
B. it has greater energy source
C. it is not easy to destroy
D. every organism has an alternative source
18. Nitrogen-fixing microbes in leguminous plants live symbiotically in
the
A. root nodules
B. tap root
C. branch roots
D. root hairs
19. The flowering period of plants in a habitat is determined by the
A. duration of sunlight
B. intensity and duration of
rainfall
C. relative humidity of the
atmosphere
D. temperature of the habitat
20. A population is defined as a collection of similar organisms that
A. behaves in the same way
B. interbreed freely
C. are found in the same habitat
D. eat the same food
21. In typical predator food chain involving secondary and tertiary
consumers, the organism become progressively
A. smaller and more numerous along the food chain
B. equal in number and size along the food chain
C. larger and fewer along the food
chain
D. parasitized along the food chain
as consumers get bigger
Use the diagram below to answer question 22 & 23
22. Which level of the pyramid has the least total stored energy?
A. E
B.
F
C. G
D. H
23. Which organism in the pyramid functions as a tertiary consumer?
A. Algea
B. Shark
C. Tadpole
D. Tilapia
24. What is the term used to describe the sum total of biotic and
abiotic factors in the environment of the organism?
A. Habitat
B. Biome
C. Ecosystem
D. Ecological niche
25. Important abiotic factors which affects all plants and animals in
the habitat are
A. temperature and turbidity
B. rainfall and relative humidity
C. salinity and wind direction
D. temperature and rainfall
26. At which trophic level would the highest accumulation of a
non-biodegradable substance occur?
A. Primary producers
B. Tertiary consumers
C. Primary consumers
D. Secondary consumers
27. Two organisms of different species, living in close association but
not dependent on each other are referred to as
A. parasites
B. commensals
C. symbionts
D. autotrophs
28. Which of the following instruments is NOT used in measuring abiotic
factors in any habitat?
A. Microscopic
B. Thermometer
C. Hygrometer
D. Wind vane
29. The depth of illumination in a water body can be measured with a
A. photometer
B. hydrometer
C. secchi disc
D. anemometer
30. In a food chain involving a primary producer, a primary consumer as
well as a secondary consumer, the sharing of trophic energy is in the form that
the
A. the primary consumer has more
energy than the primary producer
B. secondary consumer gets only a
small portion of the energy contained in the primary producer
C. energy is shared equally between
the three groups of organisms
D. secondary consumer takes up all
the energy contents of the primary consumer
Answers
1. C
7. D
13. D
19. A
25. C
2. A
8. D
14. A
20. B
26. B
3. D
9. A
15. C
21. C
27. B
4. D
10. C
16. C
22. D
28. A
5. A
11. D
17. D
23. B
29. C
6. B
12. B
18. A
24. C
30. B
THEORY
1. (SSCE, 1994 &1996) (a)
Explain the following ecological terms
(i) Population
(ii)
Habitat
(iii) Food chain
(iv) Ecosystem
(v) Environment
(b). How do rainfall and its effect
on abiotic factors influence biotic life in the biosphere?
(c). (i) Explain fully what happens
in food chain.
(ii) What lesson(s) can be learnt
from a food chain?
Solution
(a) & (b) Refer to the blog content
(c) (i). In any food chain,
transfer of energy from one organism to another occurs. Sunlight is the source
of this energy and is converted to potential chemical energy in plants by
photosynthesis, making green plants the producers. Energy is decreased when transferred from the
producer to the consumer. This is because some parts are not eaten, some
undigested as feces and others use to respire.
(c) (ii). The shorter the food chain, the greater the amount of
energy gained by the consumer.
2. (SSCE, 1997) (a) Define the following
terms
(i)
Mutualism
(ii)
Parasitism
(ii) Commensalism
(a)
Explain the interdependence of
plants and animal in a habitat
Solution
(a)
(d) In a habitat, green plants are producers. They manufacture food
and directly or indirectly are a source of food for animals. Carbon dioxide
produced by animals is utilized by plants in photosynthesis. Animals released
nitrogen waste that is utilized by plants. After the death of animals, they
decay and release nutrients to plant.
3.
(SSCE, 1999 Q5). (a) What is meant by the following?
(i)
Community
(ii) Ecosystem
(iii) Food
chain
(iv) Food web
(b) (i) Explain
briefly the term primary production.
(ii) Most primary
production goes to the decomposers rather than the primary consumers. Explain
this statement.
Solution
(a)
(b)(i) Primary production is the rate at which energy is bound
in organic material created by photosynthesis per unit area of vegetation
(c) Most of the primary production goes into the development of
tissues or normally eaten by consumers. Much of the primary production is lost through
leaf fall. When the plant dies most of the incorporated primary production is
lost to the primary consumer. Not all the parts of the plant that is eaten by
the primary consumer is utilized. A greater proportion is indigestible and
passed out as feces. Meanwhile dead plants and feces serve as the starting
point for decomposer.
4. (SSCE, 2001 Q3) Explain each of the
following terms;
(i) food chain
(ii) food web
(iii) pyramid of
biomass
(iv) decomposers
(v) pyramid of
numbers
(b) Explain to
what happens during energy flow in food chain.
Solution
Refer to the blog content
5. (SSCE 2005 Q5) Define each of the
following terms;
(i) Biomass
(ii) Producer
(iii) Primary
consumer
(iv) Food chain
(b) Describe the
flow energy through a grazing food chain.
(c) How can the
knowledge of flow of energy in a grazing food chain benefit a farmer?
Solution
Refer to notes
(b) Energy transfer from plant to primary consumer is only 10% efficient.
This is because some parts of plant are not eaten. Some of food eaten will not
be digested, which will be eliminated as feces. Some are used for metabolic
processes.
(c) Processed feed or digestible feed should be used for efficient
used of food and the shorter the food chain, the more efficient is the use of
the food provided.
6.
(SSCE, 2007 Q3) (a)(i) State four ecological factors that
common to all habitats and
(ii) List the instrument that could be used
to measure the factors named in (a)(i) above.
Solution
Refer to the blog content
7. (WASSCE 2013) 3(a)(i) Briefly describe three methods of determining food
chains in a community.
(ii) State three ways in which the knowledge of food webs could be of
importance to a fish farmer.
Solution
Direct observation: this is where the feeding habits of organism are observed in the
community using naked eye or binocular. From such observation food chains and
may be constructed.
Gut examination: this involves capturing, killing and dissecting animals to obtain
samples of their gut contents.
Radioactive/trace methods: involves the use of labeled radioactive food substances in the
field. All organisms which feed directly or indirectly on it are investigated
using a radiation detector (Geiger counter).
(ii)
1. Eliminate predators of the fish from the pond
2. Identify and introduce organisms eaten by the fish into the pond
3. Eliminate organism that compete with fish for food.
8. (WASSCE 2014) Explain briefly the
following ecological term:
i) Biosphere;
(ii) Habitat
Solution
Refer to the blog content
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