Question

With reference to aquatic ecosystems, which of the following pairs are correctly matched?

1. Autotrophs : Algae
2. Consumers : Phytoplankton
3. Decomposers : Fungi

• A. 1 and 2
• B. 1, 2 and 3
• C. 2 and 3
• D. 1 and 3

Answer 1

The correct option is D 1 and 3

A food chain is the chronological series of organisms each depending on others for food.

They are formed normally starting from producers (plants) such that an animal feeds on a plant or on another animal and it is in turn, is food for another. Such a chain or web is formed because of this interdependency.

An ecosystem is a community of living organisms that live in and interact with each other in a specific environment. An aquatic ecosystem is an ecosystem in a body of water, examples include ponds.

The autotrophic components in this ecosystem include the phytoplankton, some algae and the floating, submerged and marginal plants (found at the edges) which are able to utilise the sunlight and synthesise their own food. Hence 2 is incorrectly matched.

The consumers are represented by the zooplankton, the free swimming and bottom dwelling animals that feed on algae or phytoplanktons (microscopic marine algae).

The decomposers are organisms like fungi and bacteria, abundant at the bottom of the pond and feed on dead and decaying organic material.

Hence 1 and 3 are correctly matched and option d is correct.

Figure : Food web in a pond ecosystem