Insects are the most numerous, diverse forms of life on Earth.
The study of insects helps us understand the physiology and biology of other animals. Their actions help us comprehend animal social organization and behavior, and ecological interactions, too, can be better understood by studying insects. The quantity and quality of insect life in and around a pond or stream, for example, can indicate the presence or absence of pollution. The remarkable number of insects on Earth reflects 350 million years of evolutionary development. They exist in every freshwater and terrestrial ecosystem found on the globe.