Question

In parasitic food chain, the pyramid of number is
A. Upright
B. Inverted
C. Linear
D. Both A and B

Answer 1

Hint:Food chain involves a nutritive interaction between the living organisms of an ecosystem. In the food chain there is unidirectional flow of energy. Parasitic food chains also called auxiliary food chains begin with hosts and usually end in parasites.

Complete answer:
Ecological pyramid is a graphical respiration of the relationship between individuals present in the various trophic levels of a food chain with producers forming at the base and top carnivores at the tip.
Option A: Pyramid of number is usually upright in a grassland, ponds and lake ecosystem. Therefore, this is the incorrect option.
Option B: But in parasitic food chains, a single plant may support the growth of many herbivores and each herbivore in turn may provide nutrition to several parasites, which support many hyperparasites. From producers towards consumers, there is a reverse position as the number of organisms gradually increases, hence the pyramid is inverted in shape. Therefore, this is the correct option.
In parasitic food chains either the producer or the consumer is parasitic, so food passes to smaller organisms. The energy transfer in this type of food chain is not significant.
Example:

\[\begin{array}{*{20}{l}}
  {\mathop {Trees}\limits_{(producer)} \to \mathop {\mathop {Fruit{\text{ }}eating}\limits_{Birds} }\limits_{(Herbivores)} \to \mathop {\mathop {Lice}\limits_{bugs} }\limits_{(Parasite)} \to \mathop {\mathop {Bacteria}\limits_{fungi} }\limits_{(hyper - parasite)} } \\
  {}
\end{array}\]

Option C: Pyramid of number can never be linear as that would mean the product and consumer are equal in number which is practically not possible, therefore, this is the incorrect option.
Option D: As only option B is correct, therefore, this is the incorrect option.

Additional information: The importance of ecological pyramids are,
->They show the efficiency of energy transfer
->The present condition of ecosystem can be monitored and also any kind of damage can also be prevented
->It demonstrates feeding of different organisms in different ecosystems

Thus, the correct answer is option (B) Inverted.

Note:The 10% law was given by Raymond Lindeman. This law states that when energy is transferred from one trophic level to the other, only 10% of energy from the organic matter is passed on.