Introduction to Ecosystem Function

Q.

What is the definition of entropy?

Q. Enumerate the assumptions that we undertake in making the respiratory balance sheet. Are these assumptions valid for a living system? Compare fermentation and aerobic respiration in this context.

Q. Match the trophic levels with their correct species examples in grassland ecosystem.
$\begin{array}{cc}\text{Column - I}& \text{Column - II}\\ \text{(a) Fourth trophic level}& \text{(i) Crow}\\ \text{(b) Second trophic level}& \text{(ii) Vulture}\\ \text{(c) First trophic level}& \text{(iii) Rabbit}\\ \text{(d) Third trophic level}& \text{(iv) Grass}\end{array}$
Select the correct option:

1. a - iv, b - iii, c - ii, d - i
2. a - i, b - ii, c - iii, d - iv
3. a - ii, b - iii, c - iv, d - i
4. a - iii, b - ii, c - i, d - iv

Q.

What is the conversion of ammonia into nitrates through Nitrosomonas called?

Q.

(a) From the following group of organisms create a food chain which is the most advantageous for Human beings in terms of energy. [Hawk, Rat, Cereal Plant, Goat, Snake, Human Being]

(b) State the possible disadvantage if the cereal plant is growing in soil rich in pesticides.

(c) Construct a food web using the organisms mentioned above.

Q. 10g of a sample of potassium chlorate gave on complete decomposition 2.24 litre of oxygen at N.T.P .what is the percentage purity of the sample?

Q. With the help of a flow chart, show the phenomenon of biomagnification of DDT in an aquatic food chain. [3]

Q. A field scientist counted the number of individuals of the following from a place but jumbled up the titles of the datasheet. The organisms have been enlisted below:
i. Grass
ii. Hawks
iii. Sparrows
iv. Plant bugs
Which one of the following combinations represent the most appropriate numbers of each of the above organisms in the sequence mentioned above?

1. 13254, 5, 8376, 279
2. 8379, 279, 5, 13254
3. 13254, 279, 8376, 5
4. 13254, 5, 279, 8379

Q.

Name two microorganisms which act as decomposer? How is this activity useful to us?

Q. The shift from grain to meat diets also creates more demand for cereals as it takes 3-10 Kg of grain to produce 1 Kg of meat by animal farming. Explain this statement in the light of your knowledge of food chains?

Q.

How does an ecosystem regulate itself?

Q.

Can entropy be zero?

Q.

Give an example of entropy from everyday life.

Q. Choose the correct options:

Trophic level	Example
A. First tropic level	I. Zooplankton
B. Second tropic level	II. Phytoplankton
C. Third tropic level	III. Bear
D. Fourth tropic level	IV. Fishes

1. A-II, B-I, C-IV, D-III
2. A-I, B-II, C-IV, D-III
3. A-III, B-I, C-IV, D-II
4. A-I, B-III, C-IV, D-II

Q.

Is earthworm a decomposer?

Q.

Main objective of production/use of herbicide resistant genetically modified crops is to?

1. Encourage eco-friendly herbicides

2. Eliminate weeds from the field without the use of herbicides

3. Eliminate weeds from the field without the use of manual labor.

4. Reduce herbicide accumulation in food particles for health safety

Q.

An isolated system is that system in which

1. there is an exchange of mass with the surroundings.

2. there is an exchange of energy with the surroundings.

3. there is an exchange of mass and energy with the surroundings.

4. there is no exchange of mass and energy with the surroundings.

Q.

An ecosystem consists of

1. All the plants and animals of an area.

2. Producers, consumers, and decomposers in a particular locality.

3. A living community and its environment.

4. Carnivores and herbivores of an area.

Q. .If we completely remove the decomposers from an ecosystem, its functioning will be adversely affected, because

1. the mineral movement will be blocked

2. energy flow will be blocked
3. the rate of decomposition will be very high
4. herbivores will not receive solar energy.

Q.

Is reverse entropy possible?

Q. [5]
(a) What is a trophic level in an ecosystem ? What is 'standing crop' with reference to it ?

(b) Explain the role of the 'first trophic level' in an ecosystem.

(c) How is the detritus food chain connected with the grazing food chain in a natural ecosystem ?

Q.

The term biomagnification refers to theThe term biomagnification refers to the

1. Increase in the concentration of non-degradable pollutants as they pass through the food chain

2. Blowing up of environmental issues by man

3. Increase in population sizeGrowth of organisms due to food consumption

4. Growth of organisms due to food consumption

Q.

Biogeochemical cycles are also known as:

1. Sedimentary cycles

2. Gaseous cycles

3. Material cycles

4. Cycles of water

Q. (b) Consider the following food chains :​ ​

(i) Plants → Mice → Snakes → Hawks​
(ii) Plants → Mice → Hawks​ ​

If energy available at the producer level in both the food chains is 100 J, in which case will hawks get more energy as food and by how much? Justify your answer.​ ​

Q.

Photosynthesis is the ……. process of combustion.

Q.

During the food chain, the maximum energy is stored in

1. Decomposers

2. Producers

3. Carnivores

4. Herbivores

Q.

Which, among grass, goat, tiger and vulture, in a food chain, will have the maximum concentration of harmful chemicals in its body due to contamination of pesticides in the soil?

1. Grass since it grows in the contaminated soil

2. Goat since it eats the grass

3. Tiger since it feed on the goat which feeds on the grass

4. Vulture since it eats the tiger, which in turn eats the goat, which eats the grass.

Q. Assertion: Atmospheric nitrogen gas is always fixed by nitrogen -fixing micro-organisms.

Reason: Decomposers release nitrogen gas from dead bodies of plants and animals.

1. Both assertion and reason are true and reason is the correct explanation of assertion
2. Both assertion and reason are true but reason is not the correct explanation of assertion
3. Assertion is true but reason is false
4. Both assertion and reason are false

Q. Which of the following statements is not true for metabolism in living organisms?

1. Chemical reactions can be anabolic or catabolic.
2. Metabolism is exclusively seen only in living organisms.
3. Chemical reactions which maintain the living state of an organism is known as metabolism.
4. Metabolic reactions are not chemical reactions.

Q.

How much energy is transferred from one trophic level to next trophic level?

1. 10%
2. 20%
3. 50%
4. 1%