Organisms that get the nutrients and energy they require by feeding either directly or indirectly on producers are called consumers or heterotrophs (other-feeders)

Some consumers feed on living plants and animals; the others feed on small fragments of dead plants and animals matter, called detritus. Detritus consumers, called decomposers, digest dead tissue or wastes and absorb their soluble nutrients. Decomposers consist of two classes: called bacteria and fungi. Bacteria and fungi decomposers in turn are an important source of food for organisms such as worms and insects living in the soil and water.

There is no waste in functioning biological communities; the wastes of one form of life arc food or nutrients for other forms of life. This is how no-waste-in-naturc principle works.

Exercise 3. Study the definitions of the following words:

Ecology - study of the interaction of living organisms with each other and with their environment; study of the structure and functions of nature.

Ecosystem - community of organisms interacting with one another and with chemical and physical factors making up their environment.

Nutrient - element or compound needed for the survival, growth and reproduction of a plant or an animal.

Organism - any form of life.

Photosynthesis - complex process that takes place in cells of green plants. Radiant energy from the sun is used to combine carbon dioxide (C02) and water (H20) to produce oxygen (02) and simple nutrient, such as glucose (C6H1206).