Q.What is meant by the ecosphere or biosphere?

Ecology is the study of how organisms interact with each other and with their physical surroundings. It is traditionally split into autecology, which examines a single species in relation to its environment (its tolerance limits, feeding pattern, breeding cycle), and synecology, which examines whole groups of organisms — populations and communities — and the relationships between them.

Ecological organisation is built as a nested hierarchy, each level composed of units from the level beneath it: an individual organism belongs to a population (all interbreeding members of one species in an area), populations of different species together form a community, a community plus its physical environment forms an ecosystem, ecosystems of a similar climate and vegetation type group into a biome, and all the biomes on Earth together make up the biosphere (or ecosphere) — the global zone where life exists.

Every level in this hierarchy has properties that do not exist at the level below: a population has a birth and death rate, a community has species diversity, an ecosystem has energy flow and nutrient cycling — none of which make sense applied to a single organism alone. This is why ecologists study whole systems, not isolated individuals. …