Question

In a food relationship, the lion eats the wild beast and the wild beast eats plants.
Which of the following statements suits the given condition?
i. The lion is the prey and the wild beast is the predator.
ii. The lion is the predator and the wild beast is the prey.
iii. The lion is the primary consumer and the wild beast is the secondary consumer.
iv. The lion is the secondary consumer and the wild beast is the primary consumer.

A. (i) and (ii) only
B. (i) and (iv) only
C. (ii) and (iii) only
D. (ii) and (iv) only

Answer 1

Hint: Food chain is the linear flow of energy from one trophic level to another through food. The flow of food is very essential as the organisms gain energy mainly through the food that is passed on at different trophic levels. Predator-prey relationship is a type of relationship where predator kills the prey and eats it.

Complete answer:
The food chain is a representation of the flow of energy. The energy flow starts from the producers as they are the autotrophs. Autotrophs are the organisms that can produce their own food. So, in the above example the plants that are being consumed by the wild beast are the producers.
The wild beast which feeds on the plants is considered as the primary consumer. Primary consumers are generally the herbivorous animals. They are heterotrophic, meaning they cannot produce their own food.
Next, coming to the lion. The lion feeds on the wild beast and is considered to be the secondary consumer. The food chain is represented as follows:

According to the information provided above we can see that option (iii) is not the right option as lions are not a primary consumer. So, option C is ruled out. Since we know that the lion is the predator as it feeds on the wild beast, option (i) is also wrong. That further rules out option A and B and leaves us with option D. Option D says both (ii) and (iv) meaning the lion is the predator, wild beast is the prey, lion is the secondary consumer and wild beast is the secondary consumer. This is the right option.

Hence, the correct answer is option (D).

Note: Primary consumers, secondary consumers etc., are not fixed for any animal. An animal which is the primary consumer in one food chain may be a secondary consumer in another food chain. Apart from producers and consumers there can also be decomposers in a food chain that feed on both dead and decaying producers and consumers.