Ecology is the science of the relationship between organisms and the environment. Including aspects of both biology and Earth science, ecology first emerged in the 19th century, with the term itself coined by German scientist Ernst Haeckel. Ecology emerged out of the scientific revolution unleashed by Charles Darwin, seeking to understand the development of ecosystems, biodiversity and the entire realm of life from the smallest organisms to the entire planet.
Ecology is all about the interaction between living things and their environment, what are known as ecosystems. Ecosystems are constantly changing and evolving, sometimes changing slowly over thousands or millions of years, and sometimes quite rapidly. Ecologists have sought to organize the world into what is known as a nested hierarchy, in which life is classified from the smallest (genes), through larger, more complex systems, from species to communities to the entire biosphere of the planet.
One of the central concepts of ecology is that of biodiversity. Biodiversity is the large variety of life across the planet and its biological processes. Within biodiversity there is diversity in species, ecosystems, and genetics. Preserving biodiversity in a region is central to conservation and species preservation. Ecologists are frequently involved in environmental impact and the management of natural resources. Emerging ideas about sustainability are key to ecology.