Ecology & Environment MCQs Part III

1) Which of the following is a partial root parasite?
a) Loranthus
b) Cuscuta
c) Balanophora
d) Santalum

2) The developmental stages in a community are called
a) Climax changes
b) Biological changes
c) seral changes
d) Climatic changes

3) Phytoplanktons in the hydrosere constitute
a) Members of climax community
b) Pioneer community
c) Intermediate seral members
d) All the above

4) What are the conditions for a successful parasite?
a) It remains sticking to host for long
b) It demands the least from its host
c) It can reproduce very fast
d) The young ones of the parasite grow fast

5) One of the following cannot be a characteristic of symbiotic microbes
inside the intestine:

a) Providing vitamins to the host
b) Using extra food of host
c) Anaerobic respiration
d) Aerobic respiration

6) The association of the roots of higher plants with fungi is
a) Symbiosis
b) Mutualism
c) Parasitism
d) Hyperparasitism

7) A hyperparasite is one
a) Which kills the host
b) which completes its life cycle in one host
c) Which uses the machinery of the host to reproduce
d) parasite which lives in the body of another parasite

8) A rat feeding on a potato tuber is a
a) Carnivore
b) Decomposer
c) Producer
d) Primary consumer

9) The primary succession in a sere is
a) Subsere
b) Mesosere
c) Pioneer sere
d) None above

10) The plants which depend upon other plants forming haustoria are
a) Halophytes
b) Epiphytes
c) Xerophytes
d) Parasites

11) The tendency of an organism to maintain its population relates to
the ability to reproduce at a given rate. The force opposing it is

a) Mortality
b) Fecundity
c) Environmental resistance
d) Biotic control

12) The type of animals which is relatively more abundant in desert grasslands

a) Auroral
b) Diurnal
c) Fossorial
d) Aquatic

13) One of the following is a submerged hydrophyte:
a) Ceratophyllum
b) Utricularia
d) Lemna

14) Intergeneric crosses rarely occur in nature. To overcome this problem
the best method is

a) Embryo culture
b) Tissue culture
c) Anther culture
d) All the above

15) Plants which prefer extreme sunlight are called
a) Heliophytes
b) Halophytes
c) Sciophytes
d) Xerophytes

16) A biotic relationship between two different organisms in which one receives
benefit at the cost of the other’s life is called

a) Parasitism
b) Predation
c) Scavenging
d) Commensalism

17) In increasing order of organizational complexity, which one of the following
is in the correct sequence?

a) Population, variety, community, ecosystem
b) Population, species, community, ecosystem
c) Population, community, species
d) Species, variety, ecosystem, population

18) In a food chain the initial organisms are
a) Phototrophs
b) Top consumers in the food chain
c) Primary consumers
d) Secondary consumers

19) If phytoplanktons are destroyed in the sea then
a) Primary consumers will grow luxuriantly
b) No effect will be seen
c) Algae will get more space to grow
d) The food chain will be affected

20) The number of primary producers within a specified area would be maximum in a
a) Desert
b) Forest ecosystem
c) Grassland
d) marsh ecosystem

21) When a peacock eats snakes, which eat insects thriving on green plants, the peacock is
a) A primary decomposer
b) A primary consumer
c) At the apex of the food pyramid
d) A final decomposer

22) The Silent Valley of Kerala is preserved because
a) It contains very rare species of plants and animals
b) It is the best place for a picnic
c) It contains timber trees
d) It is the only forest in India

23) The correct path of energy flow in any ecosystem is

24) The transfer of energy from organism to organism in a natural community establishes
a) Natural barriers
b) Biological control
c) Food chains
d) All the above

25) On a global basis the maximum productivity is shown by
a) Deserts
b) Grass land
c) Forests
d) An aquatic ecosystem

26) If precise quantitative measurements are made on a confined ecosystem in a laboratory we will find the amount of which of the following to be a one-way flow rather than cyclic?
a) Potassium
b) Nitrogen
c) Free energy
d) Carbon

27) The use of energy entering an organism from the outside is 100 percent efficient in
a) Some photosynthetic bacteria only
b) All green plants
c) Unicellular green algae only
d) None of the above

28) Which is the correct sequence in the food chain of a grassland?
a) Grass-snake-insects-deer
b) Grass-insect-bird-snake
c) Bacteria-grass-rabbit-wolf
d) Grass-wolf-deer-buffalo

29) Autumn colouration of leaves appears only in
a) Deserts
b) Temperate deciduous plants
c) Evergreen plants
d) Tropical regions

30) How many trophic levels does the food chain generally have?
a) One
b) Two
c) Three
d) Three or four

31) Biologist celebrate (observe)
June as

a) World population day
b) World environment day
c) World hygiene day
d) Darwin birthday

32) Among the following which affects the biotic components of an ecosystem?
a) Flow of energy and cycling of materials
b) Consumption
c) Cycling of materials
d) Flow of energy

33) The primary or basic or main source of energy in an ecosystem is
a) Heat liberated during fermentation
b) Heat liberated during respiration
c) Sunlight (solar energy) or heat received from sun
d) Sugar stored in plants

34) Who proposed the term Ecosystem?
a) Calvin
b) Odum
c) Tansley
d) Gardner

35) The energy storage at consumer level is called
a) Net productivity
b) Net primary productivity
c) Secondary productivity
d) Gross primary productivity

36) When a man eats fish, which feeds on zooplanktons, which have eaten
small plants, the producers in the chain are

a) Man
b) Small plants
c) Fish
d) Zooplanktons

37) The abiotic component in an ecosystem is
a) Bacteria
b) Daphnia
c) Water
d) Chlorella

38) Which one of the following components of an ecosystem comes from outside?
a) Energy
b) Insects
c) Temperature
d) Oxygen

39) An ecosystem resists change because it is in a state of
a) Deficiency of light
b) Shortage of components
c) Homeostasis
d) Imbalance

40) Which of the following form the biotic component of the ecosystem?
a) Producers, consumers and decomposers
b) Only producers
c) Only producers and consumers
d) Only consumers

41) The total energy fixed by a gram plant is called
a) Gross production
b) Primary production
c) Secondary production
d) Net production

42) Homeostasis is the term used to describe the
a) Animal and plant material used in the production of homeopathic medicines
b) Tendency of biological system to resist changes so as to remain in a state of equilibrium
c) Disturbance of self regulation process and natural controls
d) Tendency of biological systems to change with the slightest change in the environment

43) A habitat of long severe winters and with a growing season limited to a few
months of summer constitutes

a) Tundra ecosystem
b) Taiga ecosystem
c) Savannah ecosystem
d) None of the above

44) About how much of the solar energy that falls on the leaves of a plant
is converted to chemical energy by photosynthesis?


45) Which of the following is the driving force of an ecosystem?
a) Carbohydrates
b) Biomass
c) Producer
d) Solar Energy

46) In which of the following is the ecological pyramid always upright?
a) Biomass
b) Number
c) Energy
d) All of the above

47) An ecosystem is
a) A closed unit
b) An open unit
c) Both an open and a closed unit depending upon the biomass present
d) Both an open and a closed unit depending upon community type

48) The ecosystem receives nitrogen from outside through
a) Biological nitrogen fixation
b) Industries
c) Electrical fixation of nitrogen
d) All the above

49) Choose the correct group of animals (with the same trophic level):
a) Deer and Bee
b) Tiger and Wild boar
c) Snake and earthworm
d) Crow and cow

50) The two major functional components of an ecosystem are
a) Food chain and decomposers
b) Energy flow and food chain
c) Mineral cycling and energy flow
d) Energy flow and decomposers

51) The decomposers in a natural ecosystem include
a) Only bacteria and fungi
b) Only microscopic animals
c) Only fungi
d) the above two types of microorganisms and microscopic animals

52) Out of the total biomass produced in the biosphere by all kinds of species,
what is the percentage of biomass produced by plants in oceans?


53) What is the percentage of land covered by forest in India?
a) 9-18%
b) 18-27%
c) 27-36%
d) More than 50%

54) Energy and nutrients enter a community by way of
a) Detritivores
b) Producers
c) Scavengers
d) Consumers

55) An ecological pyramid of biomass is a representation of the
a) Biological materials in relation to abiotic material
b) Tissue at each trophic level
c) Population in each food web
d) Energy flow through each trophic level

56) About how much of the net primary productivity of a terrestrial ecosystem
is eaten and digested by herbivores?

a) 1%
b) 10%
c) 40%
d) 90%

57) As regarding transfer of energy and energy fixation, which of the following does not follow the10% law?
a) Radiant energy to producers
b) From producers to herbivore
c) From herbivore to primary carnivore
d) From primary carnivore to secondary carnivore

58) The sequence of species through which the organic molecules in a community
pass is called a

a) Food web
b) Food chain
c) Nutrient cycle
d) Pyramid of energy

59) A group of interconnected food chains is called a
a) Pyramid of energy
b) Food web
c) Food cycle
d) Complex food chain

60) In which of the following ecosystem will the ecological pyramid be inverted?
a) Tundra
b) Desert
c) Ocean
d) Rainforest

61) About how much of the chemical energy within a producer tissue becomes chemical
energy within a herbivore tissue?

a) 50%
b) 10%
c) 30%
d) 1%

62) With regard to the ecological food chain man is a
a) Both producer and consumer
b) Producer
c) Consumer
d) Producer and consumer

63) Eutrophic lake means a
a) Lake rich in nutrients
b) Lake poor in nutrients
c) Lake poor in flora and fauna
d) Lake lacking water

64) Biogeochemical cycling means
a) Cycling of nutrients in an ecosystem
b) Cycling of water
c) Cycling of energy in an ecosystem
d) Cycling of gases between plants and the atmosphere

65) An ecosystem has two components:
a) Plants and trees
b) Weeds and trees
c) Biotic and abiotic
d) None of above

66) An ecosystem creates a
a) Food chain
b) Food web
c) Both A and B
d) None of the above

67) In a lake ecosystem the pyramid of biomass is
a) Upright
b) Inverted
c) Both are possible
d) None is correct

68) In a forest ecosystem the pyramid of biomass is
a) Upright
b) Inverted
c) Any of the two
d) None of above

69) The second trophic level in a lake ecosystem is
a) Nekton
b) Zooplankton
c) Benthos
d) Phytoplankton

70) The main indicator of soil erosion is
a) Deforestation
b) Afforestation
c) Ozone layer
d) Goats and grazing animals

71) Which one is nature’s cleaner?
a) Symbionts
b) Producers
c) Consumers
d) Decomposers and scavengers

72) Biomes are
a) Aquatic vegetation
b) Major ecological grouping of animals and plants
c) Major ecological grouping of plants
d) Indicators of climate of a place

73) Which of the following is a biome?
a) Pond
b) Wheat field
c) Deciduous forest
d) Grass field

74) The typical biome of an area having 20 to
of rainfall is

a) Desert
b) Coniferous forest
c) Deciduous forest
d) Grassland

75) Which biome exhibits distinct stratification?
a) Tundra biome
b) Tropical rainforest biome
c) Chaparral biome
d) Temperate biome

76) Which biome is treeless?
a) Temperate
b) Tundra
c) Chaparral
d) Savannah

77) Endemic plants are those plants which grow in
a) Fresh water lakes
b) Shady places
c) Tissues of other plants
d) Geographically limited areas

78) In a simple ecosystem with a grass- deer- tiger food chain, how
much tiger biomass can be supported if the grass production is
one tonne?

a) 100 kg
b) 10 kg
c) 200 kg
d) 1 kg

79) In a biotic community, the most important factor for the survival
of an animal is:

a) Predators
b) Day length
c) Soil moisture
d) Green food

80) In a food chain the largest population is that of
a) Primary consumers
b) Secondary consumers
c) Decomposers
d) Producers

81) We refer to the following as the food chain:
a) A large number of human beings forming a human chain near a source of food
b) A large number of animals near a source of food
c) Transfer of food energy from the green plants through a series of consumer organisms
d) None of these

82) Which of the following is a tertiary consumer?
a) Grass
b) Lizard
c) Snake
d) Insect

83) Primary succession refers to the development of communities on a
a) Newly exposed habitat with no record of earlier vegetation
b) Pond freshly filled with water after a dry phase
c) Forest clearing after devastating fire
d) Freshly cleared crop field

84) Which is the most stable ecosystem?
a) Mountain
b) Desert
c) Forest
d) Ocean

85) In a biotic community the primary consumers are
a) Omnivores
b) Carnivores
c) Detritivores
d) Herbivores

86) The organisms at the base of the food chain are
a) Herbivores
b) Photosynthetic plants
c) Saprophytic plants
d) Carnivores

87) Increasing accumulation of DDT in the organisms of a food chain
at a higher trophic level is known as

a) Biotic value
b) Biotic potential
c) Biological amplification
d) Biological value

88) The trophic level of a lion in a forest ecosystem is

89) The dominant second trophic level in a lake ecosystem is
a) Phytoplankton
b) Benthos
c) Nektons
d) Zooplankton

90) The importance of an ecosystem lies in
a) Flow of energy
b) Cycling of materials
c) Both of the above
d) None of the above

91) A food chain starts with
a) Nitrogen fixing organisms
b) Photosynthesizing organisms
c) Respiration
d) Decomposers

92) The absence of trees and presence of dwarf plants are characteristic

a) Tropical rain forests
b) Coniferous forests
c) Tundra
d) Deciduous forests

93) Deciduous forests are characterized by the
a) Presence of a variety of crocodiles
b) Presence of very narrow leaf trees growing together
c) Presence of a variety of grasses growing together
d) Presence of broadleaf trees growing together

94) In a marine environment, the shallow shore region is called the
a) Abyssal zone
b) Oceanic zone
c) Neritic zone
d) Bathyal zone

95) Minimum diversity is found at the
a) Moss stage
b) Climax community
c) Pioneer community
d) Seral community

96) The normal salinity of sea water is
a) 0.9%
b) 35%
c) 3.5%
d) 0.2%

97) The stability of a biotic community is governed by its
a) Population
b) Degree of diversity
c) Pioneer community
d) Environment

98) Primary succession takes much longer time than secondary succession
because it involves

a) Colonization by organisms
b) Development of soil
c) Development of a seed bank
d) All correct

99) Maximum diversity is found in
a) Tropical forests
b) Sugar cane field
c) Coral reefs
d) Estuaries

100) What changes occur during ecological succession?
a) Diversity and stability increase
b) Non living organic matter and food chains increase
c) Biomass and energy flow increase
d) All the above


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