Q.Why is a garden pond considered a convenient, self-contained example for studying the basic structure and function of an ecosystem?

An ecosystem is the basic functional unit of ecology: a self-regulating system in which a community of living organisms interacts continuously with the physical and chemical features of its surroundings, so that energy and matter flow through the whole. Ecosystems are classified by habitat into terrestrial (forest, grassland, desert) and aquatic (pond, lake, river, ocean) types, and by origin into natural ecosystems, which are self-sustaining, and artificial ecosystems (a crop field, a managed fish pond), which need continuous human input such as irrigation or fertiliser to persist in the form intended. …