Ecology is the study of how organisms interact with other organisms that share their habitat as well as with other conditions of their environment, including climate, sunlight exposure and geology. It differs from botany and zoology, in which organisms are studied primarily at the individual level, and from molecular biology and biochemistry, in which they are studied at the protein and nucleic acid levels. Although often considered as a branch of biology, ecology differs in that it also draws heavily from other branches of science, including geography, geology, and meteorology.
All species of life are finely interwoven into a delicate balance with other species and with other aspects of their environment that has been established and evolved over millions of years. A change in one species, such as an extinction or a significant mutation, or a change in some other aspect of their environment, can affect other species, including causing one, a few, or many, of them to go extinct.
Although the recording of observations about animals and plants and their relationships began in antiquity, ecology as a true science traces its roots to only the mid-nineteenth century and was influenced by Darwin's then-controversial theory of evolution. The term "ecology" was coined by the German zoologist Ernst Haeckel in 1866 to describe the "economies" of plants and animals. The field advanced rapidly during the twentieth century, in large part a result of advances in biology and other sciences but also due to the increasingly obvious effects on ecosystems from human activity.
Ecology has become an increasingly urgent field of study because of the accelerating deterioration of the natural environment, including climate change, ocean acidification, land pollution and the loss of biodiversity, and the effects that this deterioration is already starting to have on food supplies, public health, the quality of life, and even political stability. Creating greater awareness and understanding of ecology among the general public and political leaders, including teaching about it in the schools, is an important step towards implementing changes in human behavior that could slow this deterioration, and, ideally, eventually bring it to a halt.