A. Taking an example of a small pond, explain how the four components of an ecosystems function as a unit.

B. Name the type of food chain that exists in a pond.

A. The four components of an ecosystem:

Productivity: In a pond ecosystem, phytoplankton, algae, floating and submerged plants are the producers. They make food from the sunlight in the process of photosynthesis. Thus, they contribute to primary productivity.

Decomposition: Decomposers such as fungi, bacteria break down dead and decaying organic matter into simpler compounds.

Energy Flow: Energy flow from producer to different consumers in a unidirectional manner. Some of the energy is lost in the form of heat to the environment.

Nutrient cycle: The dead organic matter is mineralised and release them back to the environment for the use of autotrophs.

B. Aquatic food chain operates in a pond.

Example: