question_answer

Expain the following.

(i)  Phosphorus cycle

(ii) Pyramid of energy.

Answer:

(i)  Phosphorus cycle: Phosphorus has a sedimentary cycle. Phosphorus is deposited into the soil from the phosphate rocks and occurs in the soil in the form of orthophosphates. Absorption of phosphate is facilitated by mycorrhiza. Animals take this phosphorus by the way of food. Dead and worn out plant and animal parts become decayed. They are acted upon by phosphatising bacteria to release phosphorus in the soil.

(ii) Pyramid of energy: It is graphic representation of amount of energy trapped per unit time and area in different trophic levels of a food chain with producers forming the base and top carnivores the tip. Maximum energy content is present in producers. They convert solar energy in chemical form and stored inside organic matter manufactured by the producers.

Pyramid of energy is always upright, can never be inverted, because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step.