ecosystem

 

Ecosystem

1. Which of the following statements is correct

regarding the Ecosystem?

1. An ecosystem is a functional unit

where living organisms interact among

themselves and also with the surrounding

physical environment.

2. Vertical distribution of different species

occupying different levels is called

stratifi cation.

Select the correct option from the codes given

below:

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 and 2

2. Consider the following statements regarding

different kinds of Ecosystem:

1. Grasslands rarely receive enough rain

to support trees and does not possess

enough soil nutrients to feed large, grassy

expanses.

2. Tundra is the treeless environment of the

Arctic Circle.

3. The taiga is a region of subarctic forest

south of the Arctic Circle.

Which of the above statement/s is/are correct?

(a) 1 and 2 only

(b) 3 only

(c) 2 and 3 only

(d) 1 only

3. With respect to productivity of an ecosystem,

consider the following statements:

1. Gross primary productivity of an

ecosystem is the rate of production of

organic matter during photosynthesis.

2. Secondary productivity is defi ned as the

rate of formation of new organic matter

by producers.

Which of the above statement/s is/are

incorrect?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

 

4. Consider the following statements:

1. Decomposition is largely an oxygenrequiring

process.

2. Decomposers break down complex

organic matter into organic and inorganic

substances like carbon dioxide, water and

nutrients.

3. By the process of leaching, watersoluble

inorganic nutrients go down into the

soil horizon and get precipitated as

unavailable salts.

4. Humifi cation leads to accumulation of

a dark coloured amorphous substance

called humus that is highly resistant to

microbial action.

Which of the above statement/s is/are correct

regarding Decomposition in an Ecosystem?

(a) 1, 2 and 4 only

(b) 2, 3 and 4 only

(c) 1, 3 and 4 only

(d) 1, 2 and 3 only

5. Which of the following statements is not

correct regarding producers and consumers?

(a) In a terrestrial ecosystem, major

producers are herbaceous and woody

plants.

(b) If the animals eat other animals which

in turn eat the plants (or their produce)

they are called tertiary consumers.

(c) Primary consumers will always be

herbivores.

(d) Those animals that depend on the

primary carnivores for food are labelled

secondary carnivores.

6. Consider the following statements regarding

Detritus Food Chain (DFC):

1. It is made up of decomposers which are

heterotrophic organisms, mainly fungi

and bacteria.

2. In a terrestrial ecosystem, a much larger

fraction of energy fl ows through the

detritus food chain than through the

Grazing Food Chain (GFC).

Which of the above statement/s is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

 

7. Consider the following statements regarding

the Energy Flow in an Ecosystem:

1. Except for the deep sea hydro-thermal

ecosystem, sun is the only source of

energy for all ecosystems on Earth.

2. At each step up the food chain, only 10

percent of the energy is passed on to

the next level, while approximately 90

percent of the energy is lost as heat.

3. Of the incident solar radiation more than

50 percent of it is photosynthetically

active radiation (PAR).

Which of the above statement/s is/are correct?

(a) 1 and 2 only

(b) 2 only

(c) 1 and 3 only

(d) 3 only