Describe the processes and products of decomposition. - Biology

Answer in Brief

Describe the processes and products of decomposition.



The steps of decomposition are fragmentation, leaching, catabolism, humification, and mineralization.

a. Fragmentation: Detritivores like earthworms break down detritus into smaller fragments or particles.

b. Leaching: In this process, water-soluble inorganic nutrients percolate into the soil horizon and get precipitated as unavailable salts.

c. Catabolism: The bacterial and fungal enzymes degrade detritus into simpler inorganic substances. All of the above steps occur simultaneously.

d. Humification: It leads to the accumulation of a particularly decomposed, dark-coloured, amorphous, a colloidal organic substance called humus. Humus serves as a reservoir of nutrients. It is resistant to microbial action and undergoes decomposition at an extremely slow rate. Humus changes the soil texture and increases the capacity of water holding in the soil.

e. Mineralization: Some microorganisms degrade humus and release inorganic nutrients by the process of mineralization.

Decomposition cycle

Concept: Ecosystem
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Chapter 14: Ecosystems and Energy Flow - Exercises [Page 320]


Balbharati Biology 12th Standard HSC for Maharashtra State Board
Chapter 14 Ecosystems and Energy Flow
Exercises | Q 4.3 | Page 320


Describe the advantages for keeping the ecosystems healthy

Define the following term and give one example:


Define an ecosystem.

Give examples of any two ecosystems.

Which of the following act as decomposers in an ecosystem?
(a) Lactobacillus bacteria
(b) Cyanobacteria
(c) Putrefying bacteria
(d) Rhizobium bacteria

One of the following helps in the recycling of materials in an ecosystem. This one is :
(a) autotrophs
(b) saprotrophs
(c) omnivores
(d) carnivores

Where does all the energy in living organisms originate from?

Put a tick mark (✓) against the correct alternative in the following statement:

The term “ecosystem” is derived from the Greek word “Oikos” meaning.

Match the items in Column I with as many items as possible in Column II.

  column I Column II
1 Grass (i) Carnivore
2 Deer (ii) Decomposers
3 cobra (iii) Primary Consumer
4 Vulture (iv) Autotroph
5 Microbes (v) Scavenger

State whether true or false– Flow of nutrients in an ecosystem is unidirectional.

Reorganize the following food chain. Describe the ecosystem to which it belongs. Grasshopper – Snake – Paddy field – Eagle – Frog.

What do we learn from the story of Jadav Molai Peyang?

What is shown in the picture? Write name and trophic level of each component.

What are the meanings of following symbols? Write your role accordingly?

If frog population in paddy fields declines all of a sudden,
a) What will be the effect on paddy crop?
b) Number of which consumers will decline and which will increase?
c) Name the Indian states where paddy is cultivated on a large scale.

In a food chain autotrophic plants are present at the _______ level.

Give my information

Describe the following pictures

Define the following term and give two examples.


Answer the following question.
Write the different components of a lac-operon in E. coli. Explain its expression while in an ’open’ state.

What do you understand by the term 'environment'?

How is man-made ecosystem formed?

Name two major types of ecosystems.

In which parts of the world are tropical rainforests found?

What is a forest biome?

Differentiate between terrestrial and aquatic ecosystem.

Word ecosystem was coined by

Annual rainfall in the area of deciduous forest is

Which one is not a factor of the abiotic environment?

How do gymnosperms and angiosperms differ?

The second trophic level in a lake is ________________.

Which of the following is most often a limiting factor of the primary productivity in any ecosystem?

___________ are also called Heterotrophs.

__________ is a system of interlocking and independent food chains.

_______ is an extensive large ecosystem.

Distinguish between terrestrial biomes and Aquatic biomes.

Write a paragraph on the functions of an ecosystem.

_______________ is a chemical factor of abiotic components.

Find an odd one out.

Environment is a broad concept.

What does ecosystem mean?

What is indicated by this symbol?

Give scientific reason.

The various food chains in the ecosystem maintain the environmental balance.

Which are two components affecting the environment? State two examples of each.

Complete food chain.

Grass → _________ → Frog → ________ → Eagle

Why is it said that pollution control is important?

  1. Write the given food chain in the appropriate sequence.
    Grasshopper - Snake - Rice field - Eagle - Frog
  2. In which ecosystem given the food chain is included? Explain the ecosystem.
  3. If the frog population declines all of a sudden what will be the effect on paddy fields?

The Pacific ocean is an example of an marine ecosystem.

Identify the similar characteristics of: Lantana, African catfish and Eichhomia.

In a very short period of time, a threat to the ecosystem is caused due to the loss of ______ species.

In which one of the following organisms does the body fluid enter through nephrostome?

Arrange the following in the proper order of hydrarch succession and choose the correct option.

  1. Scrub stage
  2. Marsh - meadow stage
  3. Submerged free floating plant stage
  4. Phytoplankton
  5. Forest
  6. Submerged plant stage
  7. Reed swamp stage

Which one of the following is NOT a natural aquatic ecosystem?

An ecosystem is represented in the figure given above. This ecosystem will be self-sustaining if ______.

In the garden ecosystem, which of the following are producers?

Which one of the following is an artificial ecosystem?

The study about freshwater ecosystem is called ______.

The study of the sources, development, and history of a word is called ______.

A healthy ecosystem provides ______.

Explain the following term


Explain the following term


The ______ is the ultimate source of energy for the biosphere as a whole.

Pick out the terrestrial ecosystem.

______ is the best example of natural terrestrial ecosystem.

Ecosystem originated without human intervention is called ______.

Forest and Mountain regions are the best examples of the artificial terrestrial ecosystem.

If we protect the ecosystem, we can reduce waste by using durable goods.


Edaphic factor: Water in soil:: Physical factor: ______.

Ecosystems created and maintained by humans are called?

Match the Following:

1. Edaphic factor a. Primary consumer
2. Snails b. Non biodegradable
3. Crow c. Decomposers
4. Earthworms d. Oranic matter in soil
5. Hazardous chemicals e. Omnivores

Give two examples of artificial terrestrial ecosystems?

An ecosystem includes

Cooperation of the two photosystems of the chloroplast is required for:

Give an example of a food chain.

Define the term:

Gross Primary Productivity

Define the term:

Net Primary Productivity

  • Assertion: Biodegradable substances result in the formation of compost and natural replenishment.
  • Reason: It is due to breakdown of complex inorganic substances into simple organic substances.

Which are the major producers in an aquatic ecosystem?

When was the concept of ecosystem services given? By whom was it given?

Give the stratification seen in open seas.

In an ecosystem, bacteria are considered as______.

Explain BOD and its effects on aquatic ecosystem.


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