Question

Select the correct match from the following.
I. Sedimentary cycle – Nitrogen cycle
II. Pioneer species – Lichens
III. Secondary succession – Burned forests
IV. Pyramid of energy – Always upright

• A. I, II and IV only
• B. III only
• C. II, III and IV only
• D. II and IV only

Answer 1

The correct option is C II, III and IV only

Movement of nutrients occurs through various biotic and abiotic components of the ecosystem and is termed as biogeochemical cycles. It is of two types based on the reservoirs -

• Gaseous cycle - The reservoir exists in the atmosphere. Example: Nitrogen, carbon, etc.
• Sedimentary cycle - The reservoir exists in the earth’s crust. Examples : Sulphur, phosphorus, etc.

Hence I is incorrect.

Pioneer species are those organisms that first invade a bare area. In terrestrial ecosystems, it is usually lichen. They secrete acids to dissolve rock and form soil (weathering). Hence II is correct.

Succession where natural communities develop in an area that was earlier occupied by living organisms that were somehow lost is known as secondary succession. It begins in areas where natural biotic communities have been destroyed such as in abandoned farm lands, burned or cut forests, lands that have been flooded, etc. Hence, III is correct.

The pyramid of energy is a diagrammatic representation of energy flow from the producers (at the base) to the tertiary consumers (at the top). It is always upright because the amount of energy at a lower trophic level i.e. base of the pyramid is always more than that at a higher trophic level i.e. the apex of the pyramid. Hence IV is correct.