Question

Distinguish between
(a) Grazing food chain and detritus food chain
(b) Production and decomposition
(c) Upright and inverted pyramid
(d) Food chain and Food web
(e) Litter and detritus
(f) Primary and secondary productivity

Answer 1

(a) Grazing food chain and detritus food chain

	Grazing food chain		Detritus food chain
1	In this food chain, energy is derived from the Sun.	1	In this food chain, energy comes from organic matter (or detritus) generated in trophic levels of the grazing food chain.
2	It begins with producers, present at the first trophic level. The plant biomass is then eaten by herbivores, which in turn are consumed by a variety of carnivores.	2	. It begins with detritus such as dead bodies of animals or fallen leaves, which are then eaten by decomposers or detritivores. These detritivores are in turn consumed by their predators.
3	This food chain is usually large.	3	It is usually smaller as compared to the grazing food chain.

(b) Production and decomposition

	Production		Decomposition
1	It is the rate of producing organic matter (food) by producers.	1	It is the process of breaking down of complex organic matter or biomass from the body of dead plants and animals with the help of decomposers into organic raw material such as CO2, H2O, and other nutrients.
2	It depends on the photosynthetic capacity of the producers	2	It occurs with the help of decomposers
3	Sunlight is required by plants for primary production. 3. Sunlight is not required for decomposition by decomposers (c) Upright and inverted	3	Sunlight is not required for decomposition by decomposers

(c) Upright and inverted pyramid

	Upright pyramid		Inverted pyramid
1	The pyramid of energy is always upright.	1	. The pyramid of biomass and the pyramid of numbers can be inverted.
2	In the upright pyramid, the number and biomass of organisms in the producer level of an ecosystem is the highest, which keeps on decreasing at each trophic level in a food chain.	2	In an inverted pyramid, the number and biomass of organisms in the producer level of an ecosystem is the lowest, which keeps on increasing at each tropic level.

(d) Food chain and Food web

	Food chain		Food web
1	It is a single linear sequence of organisms	1	It contains a number of interconnected food chains.
2	Members present at higher trophic levels feed on single types of organisms.	2	One organism has alternate food sources.

(e) Litter and detritus

	Litter		Detritus
1	Litter contains all kinds of wastes generated above the ground.	1	Detritus is composed of the remains of dead plants and animals.
2	Litter contains both biodegradable and non-biodegradable matter.	2	Detritus contains only biodegradable matter.

(f) Primary and secondary productivity

	Primary productivity		Secondary productivity
1	It is defined as the amount of organic matter produced by producers per unit area over a period of time.	1	It is defined as the rate of production of organic matter by consumers over a period of time.

 

Answer 2

1.Grazing Food Chain vs. Detritus Food Chain:

• Grazing Food Chain:
  • Begins with living producers (plants).
  • Energy flow: Sun → producers → consumers.
  • Longer and more complex with multiple trophic levels.
• Detritus Food Chain:
  • Begins with dead organic matter like leaves, dead animals, rotten vegetables, etc.
  • Energy flow: Stored in dead organic matter → released by decomposers → carried by larger consumers.
  • Shorter and simpler with fewer trophic levels.

2.Production and Decomposition:

• Production:
  • Process performed by producers, creating organic matter from inorganic materials.
  • Energy flow: Sun → stored into organic molecules.
• Decomposition:
  • Process carried out by decomposers, breaking down complex dead organic matter into simpler molecules.
  • Energy flow: Organic molecules → used by decomposers for their growth.

3.Upright and Inverted Pyramids:

• Upright Pyramids:
  • Highest number of organisms at the top level.
  • Large number of producers at the base.
• Inverted Pyramids:
  • Lowest number of organisms at the top level.
  • Small numbers of producers at the base.

4.Food Chain and Food Web:

• Food Chain:
  • Single flow or list of who eats whom within the ecosystem.
  • Starts with the producer and ends with the decomposer.
• Food Web:
  • Outline of how different food chains are connected within the ecosystem.
  • Multiple paths, interconnected beginning and ending.

5.Litter and Detritus:

• Litter:
  • Dead organic matter present on the surface of the soil, e.g., dead leaves, dead animals, etc.
• Detritus:
  • Present below the surface of the soil, produced by detrivores or decomposers.

6.Primary and Secondary Productivity:

• Primary Productivity:
  • Rate of synthesis of organic matter by producers, comparatively higher than secondary productivity.
• Secondary Productivity:
  • Rate of synthesis of organic matter by consumers, very small and decreases with each trophic level.