Ecology (from
οἶκος, "house"; -λογία, "study of") is the
scientific study of the relationships that living
organisms have with each other and with their abiotic
environment. Topics of interest to ecologists include the
diversity, distribution, amount (
biomass), number (
population) of organisms, as well as competition between them within and among
ecosystems. Ecosystems are composed of dynamically interacting parts including
organisms, the
communities they make up, and the non-living components of their environment. Ecosystem processes, such as
primary production,
pedogenesis,
nutrient cycling, and various
niche construction activities, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life history traits, and the variety of organisms is called
biodiversity. Biodiversity, which refers to the varieties of
species,
genes, and
ecosystems, enhances certain
ecosystem services.
Ecology is an
interdisciplinary field that includes
biology and
Earth science. The word "ecology" ("Ökologie") was coined in 1866 by the German scientist
Ernst Haeckel (1834–1919). Ancient Greek philosophers such as
Hippocrates and
Aristotle laid the foundations of ecology in their studies on
natural history. Modern ecology transformed into a more rigorous
science in the late 19th century.
Evolutionary concepts on adaptation and
natural selection became cornerstones of modern
ecological theory. Ecology is not synonymous with environment,
environmentalism, natural history, or
environmental science. It is closely related to
evolutionary biology,
genetics, and
ethology. An understanding of how biodiversity affects ecological function is an important focus area in ecological studies. Ecologists seek to explain:
Life processes, interactions and
adaptationsThe movement of materials and
energy through living communities
The
successional development of ecosystems, and
The
abundance and distribution of organisms and biodiversity in the context of the
environment.
Ecology is a human science as well. There are many practical applications of ecology in
conservation biology, wetland management,
natural resource management (
agroecology,
agriculture,
forestry,
agroforestry,
fisheries), city planning (
urban ecology),
community health,
economics,
basic and
applied science, and human social interaction (
human ecology). Organisms and resources compose
ecosystems which, in turn, maintain
biophysical feedback mechanisms that moderate processes acting on living (
biotic) and nonliving (
abiotic) components of the planet. Ecosystems sustain life-supporting functions and produce
natural capital like biomass production (food, fuel, fiber and medicine), the regulation of
climate, global biogeochemical cycles, water filtration,
soil formation, erosion control, flood protection and many other natural features of scientific, historical, economic, or intrinsic value.