Question

Which of the following trophic levels includes a bird feeding on both insects and berries?
(a) Primary consumer
(b) Secondary consumer
(c) Tertiary consumer
(d) Both A and B
(e) Both A and C

Answer 1

Hint: The second trophic level includes those organisms that feed on plants and berries while the third trophic level includes organisms that feed on insects. There are certain organisms that feed on both plants and insects.

Complete answer:
The food chain, in ecology, the sequence of transfers of matter and energy in the form of food from organism to organism. The food chains are intertwined as the organisms eat different types of plants and animals. In ecology, the definition of the trophic level is that it is the position held by an organism in a food chain. However, the food chain is the succession of those organisms that eat other organisms and may, in turn, be eaten themselves. The number of steps an organism takes from the start of the chain is the trophic level of that organism. So, the bird that eats berries or plants will come under the primary consumer and when it will eat insects then it will come under the secondary consumer.
The primary energy source in any ecosystem is the sun and the solar radiation from it provides the input of energy which is used by primary producers, also known as autotrophs. The primary producers are those that perform photosynthesis and their own food, they involve plants and algae. The primary consumer constitutes the first trophic level while the consumer occupies the rest of the trophic levels. The consumers do not produce their own food and require nutrition from others hence they are named herbivores. They occupy the second trophic level and are called primary consumers as they consume primary producers to get energy. The trophic level three, four, and five constituents of carnivores and omnivores. Carnivores are those organisms that consume other animal’s flesh while omnivores are those organisms that consume both plants and animals. Both carnivores and omnivores occupy the third trophic level as they consume herbivores are called the secondary consumers while those carnivores and omnivores that consume secondary consumers and occupy the fourth trophic level are called tertiary consumers. And lastly, the trophic level present at the top of the food chain consists of animals that are called predators and called the fifth trophic level.

So, the correct answer is ‘Both A and B’.

Note:
Raymond Lindeman developed the concept of a trophic level in 1942 based on the terminology of another scientist August Thienemann (1926): "producers", "consumers" and "reducers" (modified to "decomposers" by Lindeman). In ecology, the flow of energy through a food chain is referred to as the energy flow and is the focus of study in ecological energetics.