The mechanism of the biological clock has long proved elusive; however, a molecular basis for such a clock in the fruit fly Drosophila has been discovered, and similar mechanisms may well apply in other organisms.

It is based on the cyclical rise and fall in the concentrations of certain proteins which form part of a negative feedback loop that controls transcription of their own genes.

The most famous successful example was the introduction of the gray moth, Cactoblastis cactorum, into Australia to control the prickly pear, Opuntia inermis, which was over running vast tracts of land. The moth's caterpillars eat the shoots of the plant.

Another example is the introduction of parasitic wasps that lay their eggs inside the eggs of pest insects; such as, corn borers that attack corn (maize).

Populations of insect pests may also be reduced by releasing sterile males to mate with the females, or by using sex-attractant chemicals (pheromones) to trap males or females.

The concept is applied primarily in drinking water management.

It occurs in self-purification of water bodies and in activated sludge wastewater treatment.

Perspectives about how some scientists are utilizing the forces of nature through biomimetics or biomimesis; that is, mimicking nature with technology.

Don't confuse this field of science with a similar term known as biometrics.