biology MCQs - 12th class Chapter 11 Mcqs

1

The term 'ecology' was originally coined by which German zoologist?

A

Charles Eltan

B

Joseph Grinnell

C

Ernst Haeckel

D

Gregor Mendel

2

What does the Greek word 'oikos' mean in the context of ecology?

A

The study of

B

The family household

C

The environment

D

Life

3

Which of the following are considered biotic components of an ecosystem?

A

Atmosphere, climate, soil

B

Animals, plants, fungi, micro-organisms

C

Water, soil, energy

D

Gravity, topography, temperature

4

A group of interbreeding individuals of the same species occurring together in space and time is called a?

A

Community

B

Ecosystem

C

Population

D

Biome

5

All the populations within an ecosystem are collectively known as a?

A

Biome

B

Community

C

Habitat

D

Niche

6

Major types of ecosystems that occupy broad geographical regions are called?

A

Biomes

B

Habitats

C

Niches

D

Populations

7

Which term refers to the thin layer of earth in which all living organisms exist?

A

Lithosphere

B

Hydrosphere

C

Atmosphere

D

Biosphere

8

Who first proposed the term 'niche' in ecology in 1917?

A

Ernst Haeckel

B

Charles Eltan

C

Joseph Grinnell

D

A.G. Tansley

9

The definition of a niche as 'the basic role of an organism in the community' was given by?

A

Joseph Grinnell

B

Ernst Haeckel

C

A.G. Tansley

D

Charles Eltan

10

The study of a single population's relationship to its environment is called?

A

Synecology

B

Community Ecology

C

Autecology

D

Biome Ecology

11

The study of the relationship of different communities to their environment is known as?

A

Autecology

B

Synecology

C

Population Ecology

D

Nicheology

12

Producers in an ecosystem are also known as?

A

Heterotrophs

B

Autotrophs

C

Decomposers

D

Consumers

13

Which group of organisms obtains energy from dead and decaying plants and animals?

A

Producers

B

Primary Consumers

C

Secondary Consumers

D

Decomposers

14

A simple food chain like 'grass -> caterpillar -> blue bird -> eagle' consists of how many trophic levels?

A

Two

B

Three

C

Four

D

Five

15

The first trophic level (T1) in a food web is always occupied by?

A

Primary consumers

B

Producers

C

Secondary consumers

D

Decomposers

16

The sequence of changes in the community structure of an ecosystem over time is called?

A

Succession

B

Predation

C

Symbiosis

D

Competition

17

The first hardy invaders that initiate succession are called?

A

Climax species

B

Pioneers

C

Successors

D

Colonizers

18

Succession that starts on bare rock where no life existed before is called?

A

Secondary succession

B

Hydrosere

C

Climax succession

D

Primary succession

19

Primary succession starting in a pond is specifically called?

A

Xerosere

B

Mesosere

C

Hydrosere

D

Lithosere

20

Which plants are adapted to withstand prolonged periods of water shortage?

A

Hydrophytes

B

Mesophytes

C

Xerophytes

D

Halophytes

21

In xerosere, which stage follows the crustose lichen stage?

A

Moss stage

B

Foliage lichen stage

C

Herbaceous stage

D

Shrub stage

22

The stable, self-sustaining community at the end of succession is called the?

A

Pioneer community

B

Seral community

C

Climax community

D

Transitional community

23

An animal that preys on other animals is called a?

A

Prey

B

Parasite

C

Host

D

Predator

24

An association where a parasite lives inside the body of the host is known as?

A

Ectoparasitism

B

Mutualism

C

Commensalism

D

Endoparasitism

25

The relationship between a fungus and an alga in lichens is an example of?

A

Parasitism

B

Commensalism

C

Mutualism

D

Predation

26

Mycorrhiza is a symbiotic association between fungi and the roots of which type of plants?

A

Plants in alkaline soil

B

Aquatic plants

C

Plants in acid soil

D

Desert plants

27

The relationship where one organism benefits and the other is not affected at all is called?

A

Mutualism

B

Parasitism

C

Commensalism

D

Symbiosis

28

The remora fish attaching to a shark is a classic example of?

A

Mutualism

B

Commensalism

C

Parasitism

D

Predation

29

What is the ultimate result of over-grazing on pastureland?

A

Increased soil fertility

B

Formation of a forest

C

Creation of totally barren land

D

Maintenance of grassland

30

Nutrient elements required by organisms in large amounts are called?

A

Micronutrients

B

Trace elements

C

Macronutrients

D

Biogenic elements

31

What percentage of the gases in the atmosphere is composed of nitrogen?

A

21%

B

0.03%

C

78%

D

1%

32

The process where soil bacteria and fungi decompose nitrogenous compounds into ammonia is?

A

Nitrification

B

Denitrification

C

Assimilation

D

Ammonification

33

The oxidation of ammonia or ammonium ions by several soil bacteria is known as?

A

Ammonification

B

Nitrification

C

Denitrification

D

Nitrogen fixation

34

In what form is most nitrogen moved from the soil into the roots of plants?

A

Ammonia

B

Nitrite

C

Ammonium

D

Nitrate

35

The process where bacteria break down nitrates, releasing nitrogen gas back to the atmosphere is?

A

Nitrification

B

Ammonification

C

Nitrogen fixation

D

Denitrification

36

What is the total amount of energy fixed by plants in an ecosystem called?

A

Net primary production

B

Gross primary production

C

Secondary production

D

Community production

37

The amount of energy left after plants have met their own respiratory needs is?

A

Gross primary production

B

Net primary production

C

Standing crop

D

Biomass

38

Approximately what percentage of the total energy from the sun is trapped by producers?

A

100%

B

50%

C

10%

D

1%

39

Between trophic levels, what percentage of energy is typically lost as heat due to respiration?

A

10-20%

B

30-40%

C

50-60%

D

80-90%

40

Who defined niche as the 'occupation' of a species?

A

Joseph Grinnell

B

Charles Eltan

C

Ernst Haeckel

D

A.G. Tansley

41

In the nitrogen cycle, which process is carried out by symbiotic bacteria in root nodules of legumes?

A

Denitrification

B

Nitrification

C

Biological N-fixation

D

Ammonification

42

Which of the following is an example of a micronutrient?

A

Carbon

B

Nitrogen

C

Phosphorus

D

Iron

43

A food web is described as?

A

A single pathway of energy flow

B

The combination of many food chains

C

The interaction between two species

D

A pyramid of numbers

44

What is the main function of decomposers like fungi and bacteria?

A

To produce organic food

B

To consume producers

C

To release chemical elements as ions

D

To form the first trophic level

45

The physical or abiotic components of an ecosystem include?

A

Atmosphere, hydrosphere, lithosphere

B

Producers, consumers, decomposers

C

Plants, animals, fungi

D

Population, community, biome

46

The second trophic level (T2) in a food chain is composed of?

A

Producers

B

Secondary consumers

C

Primary consumers

D

Tertiary consumers

47

What does 'xerosere' refer to?

A

Succession in a pond

B

Succession in a forest

C

Succession on dry soil or habitat

D

Succession after a fire

48

Which of these is NOT a stage in xerosere?

A

Crustose lichen stage

B

Moss stage

C

Phytoplankton stage

D

Shrub stage

49

In mycorrhiza, the host plant provides the fungus with an enzyme to digest what?

A

Proteins

B

Fats

C

Minerals

D

Carbohydrates

50

Which of the following is an example of predation?

A

Lichen

B

Mycorrhiza

C

Fox/rabbit

D

Remora/shark