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13. Outline salient features of carbon cycling in an ecosystem.

Salient features of carbon cycling are as follows 1. Carbon cycling occurs through atmosphere, ocean and through the living and dead organisms. 2. Most of the carbon is fixed by plants during the process of photosynthesis and returns to the atmosphere in the form of CO2 during respiration. 3. Burning of wood, forest fire and combustion of organic matter, fossil fuel, and volcanic activity are...

12. Write important features of a sedimentary cycle in an ecosystem.

The important features of the sedimentary cycle are as follows: 1. These nutrient cycles have their reservoirs in the Earth's crust. 2. Sulphur, calcium, phosphorous etc have sedimentary cycles. 3. Sedimentary cycles are slow, they take more time to complete their circulation and are considered less perfect cycles

11. Give an account of energy flow in an ecosystem

Energy Flow in an ecosystem All living organisms are dependent for their food on producers, directly or indirectly. There is a unidirectional flow of energy from the sun to producers and then to consumers. Photosynthetically active radiation (PAR) is responsible for the synthesis of food by plants. Animals obtain their food from plants, so they are called consumers. The process of eating and...

10. Define decomposition and describe the processes and products of decomposition.

Decomposition is the process of breaking down of complex organic matter of detritus into inorganic substances such as carbon dioxide, water and nutrients. Dead remains of plants and animals constitute detritus. The process of decomposition involves steps like fragmentation, leaching, catabolism, humification and mineralization. 1. Fragmentation of Detritus- In this step, the detritus is broken...

9. What is primary productivity? Give brief description of factors that affect primary productivity.

Primary productivity refers to the amount of organic matter or biomass produced by producers per unit area over a period of time. The primary productivity of an ecosystem depends upon a number of factors such as light, temperature, water, precipitation, availability of nutrients etc.

8.  Define ecological pyramids and describe with examples, pyramids of number and biomass.

Ecological pyramid- The graphical representation of an ecological parameter such as number, biomass or energy, sequence wise in various trophic levels of a food chain in which producers are at the base, herbivores in the middle and carnivores at the top level. Ecological pyramids can be upright, inverted, or spindle-shaped.  The three common types of ecological pyramids include the pyramid of...

7. Describe the components of an ecosystem.

An ecosystem refers to be the functional unit of nature in which living organisms interact among themselves and also with their surrounding physical environment in order to perform nutrient cycling, energy flow, decomposition and productivity. There are many types of ecosystems such as pond ecosystem, forest ecosystem etc. Components of ecosystem  The components of the ecosystem can be divided...

6. Distinguish between

(f) Primary and secondary productivity

Primary productivity    Secondary productivity Primary productivity refers to the amount of organic matter produced by producers per unit area over a period of time  Secondary productivity refers to the rate of production of organic matter by consumers over a period of time   

6. Distinguish between 

    (e) Litter and detritus

Litter      Detritus The term litter refers to any kind of waste generated                                 The term detritus refers to the dead waste of plants and animals bodies Litter can be biodegradable as well as non- biodegradable Detritus is biodegradable  

6. Distinguish between 

(d) Food chain and Food web

Food chain Food web                                         A series of living organisms present at different trophic levels and related to food habits An interconnected web of a   number of food chains.                                            The members at higher trophic level feed upon the members of lower trophic levels. Different organisms have more than one food sources  

6. Distinguish between 

(c) Upright and inverted pyramid


Upright pyramid Inverted pyramid Upright pyramids show a decrease in number and biomass from producer level to the tertiary consumer level Inverted pyramids depict an increase in number and biomass from producer level to tertiary consumer level Pyramid of energy is upright Pyramid of biomass and number can be inverted  

6. Distinguish between 

(b) Production and decomposition

Production     Decomposition It is the process of formation of organic matter by producers by means of photosynthesis It is the process of breakdown of complex organic matter into simples organic molecules It requires sunlight It can take place in the absence of sunlight also  

6. Distinguish between

(a) Grazing food chain and detritus food chain

Grazing food chain Detritus food chain  Solar energy is utilised                                                                    Biomass energy stored in bodies of plants and animals is utilised The grazing food chain starts from producers The detritus food chain starts from detritus i.e. dead plants and animals It includes a number of trophic levels Detritus food chain includes a...

5 . What is the percentage of photosynthetically active radiation (PAR) in the incident solar radiation?

(a) 100%

(b) 50 %

(c) 1-5%

(d) 2-10%

(b) 50% Out of total incident solar radiation, 50 % is formed by photosynthetically active radiation

4. Secondary producers are

(a) Herbivores

(b) Producers

(c) Carnivores

(d) None of the above

(d) None of the above In a food chain, plants are the only producers, there are no other producers. Herbivores and carnivores are primary and secondary consumers respectively. 

3. The second trophic level in a lake is

(a) Phytoplankton

(b) Zooplankton

(c) Benthos

(d) Fishes

(b) Zooplankton In a lake, the first trophic level is formed by phytoplankton while the second trophic level is formed by zooplankton.

2. Which one of the following has the largest population in a food chain?

(a) Producers

(b) Primary consumers

(c) Secondary consumers

(d) Decomposers

(d) Decomposers Decomposers are microorganisms including fungi and bacteria. These break down the remains of dead plants and animals. Decomposers form the largest community of organisms in a food chain. 

1. Fill in the blanks.

    (e) The major reservoir of carbon on earth is_________.

The major reservoir of carbon on earth is ocean

1. Fill in the blanks.

(d) Common detritivores in our ecosystem are_________.

Common detritivores in our ecosystem are earthworms

1. Fill in the blanks.

(c) In aquatic ecosystems, the limiting factor for the productivity is_________.

In aquatic ecosystems, the limiting factor for the productivity is light