All of the ecosystems of the earth, together, form the biosphere. The biosphere is that portion of the earth within which life exists. It includes all oceans and freshwater, the lower layers of the atmosphere and the outer skin of the earth’s crush—the rocks and soil of the earth’s surface. Within the biosphere all of the functions [...]
Environment is the sum of substances & forces external to the organism in such a way that it affects the organism’s existence. In relation to man, the environment constitutes of air, land, water, flora and fauna because these regulate the man’s life. Environment is a multi-dimensional systems of complex interrelationships in a continuing state of [...]
Trophic level is a step or division of food chain which is characterized by the method of obtaining its food. The number of trophic levels are equal to the number of steps in the food chain. The two fundamental trophic levels are producers and consumers.
A group of species belonging to a trophic level which exploits a common resource base in a similar fashion is known as ecological guild. Examples: Nectar feeding birds, grazing animals.
An ecad of a plant species is a population of individuals which although belong to the same genetic stock (genetically similar) but differ in vegetative characters such as size, shape, number of leaves, stem etc.
