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Outline salient features of carbon cycling in an ecosystem.

Carbon cycle is the simplest of all nutrient cycles. Its salient features are :

1. The reservoirs of carbon are : air( as Carbon dioxide), Water ( as dissolved carbon), earth's crust and ocean ( as bicarbonates) and fossil fuels.

2. Carbon dioxide is used by green plants for the process of photosynthesis and oxygen is released as a by-product. The fixed carbon enters the food chain and passed to herbivores, carnivores, decomposers. About 4 x 10¹³ kg of carbon is fixed in biosphere through photosynthesis annually.

2. CO₂ production and return to atmosphere.

(a) Carbon dioxide is released into the atmosphere by respiration of producers and consumers.

(b) It is also released by decomposition of organic wastes and dead bodies by decomposers by the action of bacteria and fungi of decay.

(d) Volcanic eruptions and hot springs also release C0₂ into the atmosphere.

(e) Weathering of carbonate-containing rocks by the action of acids also add C0₂ to the atmosphere.

Fill in the blanks with suitable words :
1. Plants are called as .......................because it fixes carbon dioxide.

2. In ecosystem, dominated by trees, the pyramid is.......................type.

3. In aquatic ecosystems, the limiting factor for the productivity is.......................

4. Common detritivores in our ecosystem are.......................

5. The major reservoir of carbon is.......................

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

Define decomposition and describe the processes and products of decomposition.

Give an account of energy flow in an ecosystem.

Write important features of a sedimentary cycle in an ecosystem.

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

The second trophic level in a lake is :

Secondary producers are :

What is the percentage of photosynthetically active radiation (PAR), if incident solar radiation is considered 100% ?

Distinguish between the following :
(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.

Describe the components of an ecosystem.

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

Describe the advantages for keeping the ecosystems healthy.

Explain the carbon cycle with the help of a simplified model.

Explain how does:

(a) a primary succession start on a bare rock and reach a climax community?
(b) the algal bloom eventually choke the water body in an industrial area?

(a) Explain primary productivity and the factors that influence it.

(b) Describe how do oxygen and chemical composition of detritus control decomposition?

It is often said that the pyramid of energy is always upright. On the other hand, the pyramid of biomass can be both upright and inverted. Explain with the help of examples and sketches.

(a) Explain the significance of ecological pyramids with the help of an example.
(b) Why are the pyramids referred to as upright or inverted?

(a) Taking an example of a small pond explain how the four components of an ecosystem function as a unit.
(b) Name the type of food chain that exists in a pond.