Saprophytes and Decomposers

Q.

What are decomposers in a food web?

Q.

Question 30
We do not clean ponds or lakes, but an aquarium needs to be cleaned. Why?

Q.

What are decomposers? How are they useful?

Q. Which one of the following is incorrect with respect to the decomposition process?

1. Catabolism - last step of decomposition carried out by saprophytic organisms.
2. Fragmentation - Carried out by organisms such as earthworms.
3. Humification - leads to the accumulation of a dark coloured humus which undergoes microbial action at a very fast rate.
4. Leaching - water soluble inorganic nutrients leach to the upper layers of soil by percolation of water into soil particles.

Q. Assertion [A]: Food chains start with photosynthesis and end with decomposition.
Reason [R]: In an ecosystem, plants produce food and decomposers help in the decay of dead matter.

1. A is true and R is false
2. Both A and R are true R does not explain A
3. Both A and R are false
4. Both A and R are true and R explains A

Q.

Microorganisms play an important role in the ecosystem. Explain briefly.

Q.

Question 2
Give any two ways in which biodegradable substances would affect the environment.

Q.

Destruction of toxic chemicals and harmful pollutants with the help of plants is called phytoremediation

1. True

2. False

Q.

Question 1
Which of the following groups contain only biodegradable items?
1. Glass, flowers and leather
2. Grass, wood and plastic
3. Fruit-peels, cake and lime-juice
4. Cake, wood and grass

Q.

Bacteria plays important role in an ecosystem because

1. they act as producers.

2. they act as decomposers.

3. they act as consumers.

4. they act as parasites.

Q.

Decomposers are the microorganisms like _________ and __________.

Q. The decomposers in an ecosystem ______.

1. convert inorganic materials to simpler forms.
2. convert organic materials to inorganic forms.
3. convert inorganic materials into organic compounds.
4. do not breakdown organic compounds.

Q. The biodegradable material among the given options is
(a) paper
(b) plastic
(c) detergent
(d) glass

Q. Which of these is the major function of bacteria and fungi in an ecosystem?

1. Absorption of inorganic nutrients
2. Degradation of inorganic matter
3. Degradation of organic matter
4. Fixation of nitrogen and phosphorus

Q.

Which of the following is true regarding decomposition of dead animals or plants?

1. Nutrients in the soil are absorbed by plants and decomposers.

2. Complex organic substances are converted into simpler inorganic substances.

3. Complex inorganic substances are converted into simple organic substances.

4. Fertility of soil decreases gradually.

Q. ........... is a suspension of microorganism which when added to the soil, it colonises the rhizosphere.

1. Biofuels
2. Biofertilizer
3. Biodiesel
4. None of the above

Q.

Give one word / a few words for the following:

Organisms which help not only in cleaning the environment but also in the recycling of minerals.