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Ecology (from Greek: οἶκος, "house", or "environment"; -λογία, "study of") is a branch of biology that studies the interactions among organisms and their biophysical environment, which includes both biotic and abiotic components. Topics of interest include the biodiversity, distribution, biomass, and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis, nutrient cycling, and niche construction, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life history traits.

Ecology is not synonymous with environmentalism, natural history, or environmental science. It overlaps with the closely related sciences of evolutionary biology, genetics, and ethology. An important focus for ecologists is to improve the understanding of how biodiversity affects ecological function. Ecologists seek to explain:

  • Life processes, interactions, and adaptations
  • The movement of materials and energy through living communities
  • The successional development of ecosystems
  • The abundance and distribution of organisms and biodiversity in the context of the environment.

Ecology has practical applications 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). For example, the Circles of Sustainability approach treats ecology as more than the environment 'out there'. It is not treated as separate from humans. Organisms (including humans) and resources compose ecosystems which, in turn, maintain biophysical feedback mechanisms that moderate processes acting on living (biotic) and non-living (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.

The word "ecology" ("Ökologie") was coined in 1866 by the German scientist Ernst Haeckel. Ecological thought is derivative of established currents in philosophy, particularly from ethics and politics. Ancient Greek philosophers such as Hippocrates and Aristotle laid the foundations of ecology in their studies on natural history. Modern ecology became a much more rigorous science in the late 19th century. Evolutionary concepts relating to adaptation and natural selection became the cornerstones of modern ecological theory.

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New beech leaves, Grib Forest in the northern part of Denmark
Pictured left: New beech leaves, Grib Forest in the northern part of Denmark

The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species. The natural environment is contrasted with the built environment, which comprises the areas and components that are strongly influenced by humans. A geographical area is regarded as a natural environment. The concept of the natural environment can be distinguished by components:

Earth science generally recognizes 4 spheres, the lithosphere, the hydrosphere, the atmosphere, and the biosphere as correspondent to rocks, water, air, and life. Some scientists include, as part of the spheres of the Earth, the cryosphere (corresponding to ice) as a distinct portion of the hydrosphere, as well as the pedosphere (corresponding to soil) as an active and intermixed sphere. Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth. There are four major disciplines in earth sciences, namely geography, geology, geophysics and geodesy. These major disciplines use physics, chemistry, biology, chronology and mathematics to build a qualitative and quantitative understanding of the principal areas or spheres of the Earth system.

Biomes are terminologically similar to the concept of ecosystems, and are climatically and geographically defined areas of ecologically similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, often referred to as ecosystems. Biomes are defined on the basis of factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest, woodland, savanna), and climate. Unlike ecozones, biomes are not defined by genetic, taxonomic, or historical similarities. Biomes are often identified with particular patterns of ecological succession and climax vegetation.

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Animal diversity.png
Credit: Composite image created by User:Medeis

There are many diverse animal species on the planet.

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Howard Thomas Odum (1924 – 2002) (also known as 'Tom' or 'H.T.') was an American ecologist. He is known for his pioneering work on ecosystem ecology, and for his provocative proposals for additional laws of thermodynamics, informed by his work on general systems theory. Odum was the third child of the American sociologist Howard W. Odum, and the brother of ecologist Eugene Odum.

In 1950 Howard earned his Ph.D. in zoology at Yale University, under the guidance of G. Evelyn Hutchinson. His dissertation was titled The Biogeochemistry of Strontium: With Discussion on the Ecological Integration of Elements. This step took him from his early interest in ornithology and brought him into the emerging field of systems ecology. Through this a meteorologist "analysis of the global circulation of strontium, anticipated in the late 1940s the view of the earth as one great ecosystem."

While at Yale, Howard began his life-long collaborations with his brother Eugene Odum. In 1953, they published the first English-language textbook on systems ecology, Fundamentals of Ecology. Howard wrote the chapter on energetics which introduced his energy circuit language. They continued to collaborate, in research as well as writing, for the rest of their lives. For Howard, his energy systems language (which he called "energese") was itself a collaborative tool.

The Center for Wetlands at the University of Florida, founded in 1973 by Howard T. Odum, is the first of its kind in the world to especially study wetlands. From 1956 to 1963, Odum worked as Director of the Marine Institute of the University of Texas. During this time, he became aware of the interplay of ecological-energetic and economic forces. He then taught at the University of North Carolina at Chapel Hill, where he was in the Department of Zoology, and one of the professors in the new Curriculum of Marine Sciences until his move to the University of Florida in 1970. He then taught at the Environmental Engineering Sciences Department for 26 years until his retirement in 1996. He also started and directed the Center for Environmental Policy at the University of Florida and founded the University's Center for Wetlands in 1973, the first of its kind in the world that is still in operation today.

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White Tank Mountains Regional Park - Two Ocotillos - 60134.JPG
...desert ecology is the sum of the interactions between both biotic and abiotic processes in arid regions, and it includes the interactions of plant, animal, and bacterial populations in a desert habitat, ecosystem, and community? Some of the abiotic factors also include latitude and longitude, soil, and climate. Each of these factors have caused adaptations to the particular environment of the region.
(Pictured left: Two Ocotillo plants, in White Tank Mountains Regional Park)
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For many of us, water simply flows from a faucet, and we think little about it beyond this point of contact. We have lost a sense of respect for the wild river, for the complex workings of a wetland, for the intricate web of life that water supports.
— Sandra Postel

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Environmental Research Letters is an open-access electronic-only peer-reviewed scientific journal covering research in all aspects of environmental science. Numerical modelling or simulation, as well as theoretical and experimental approaches to environmental science form the core content. Approaches from a range of physical and natural sciences, economics, and political, sociological and legal studies are also present.

Official website: Environmental Research Letters

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