Systems theory is the transdisciplinary study of systems, i.e. cohesive groups of interrelated, interdependent components that can be natural or human-made. Every system has causal boundaries, is influenced by its context, defined by its structure, function and role, and expressed through its relations with other systems. A system is "more than the sum of its parts" by expressing synergy or emergent behavior.
Theoretical ecology is the scientific discipline devoted to the study of ecological systems using theoretical methods such as simple conceptual models, mathematical models, computational simulations, and advanced data analysis. Effective models improve understanding of the natural world by revealing how the dynamics of species populations are often based on fundamental biological conditions and processes. Further, the field aims to unify a diverse range of empirical observations by assuming that common, mechanistic processes generate observable phenomena across species and ecological environments. Based on biologically realistic assumptions, theoretical ecologists are able to uncover novel, non-intuitive insights about natural processes. Theoretical results are often verified by empirical and observational studies, revealing the power of theoretical methods in both predicting and understanding the noisy, diverse biological world.
Ecological economics, bioeconomics, ecolonomy, eco-economics, or ecol-econ is both a transdisciplinary and an interdisciplinary field of academic research addressing the interdependence and coevolution of human economies and natural ecosystems, both intertemporally and spatially. By treating the economy as a subsystem of Earth's larger ecosystem, and by emphasizing the preservation of natural capital, the field of ecological economics is differentiated from environmental economics, which is the mainstream economic analysis of the environment. One survey of German economists found that ecological and environmental economics are different schools of economic thought, with ecological economists emphasizing strong sustainability and rejecting the proposition that physical (human-made) capital can substitute for natural capital.
Agroecology is an academic discipline that studies ecological processes applied to agricultural production systems. Bringing ecological principles to bear can suggest new management approaches in agroecosystems. The term can refer to a science, a movement, or an agricultural practice. Agroecologists study a variety of agroecosystems. The field of agroecology is not associated with any one particular method of farming, whether it be organic, regenerative, integrated, or industrial, intensive or extensive, although some use the name specifically for alternative agriculture.
Industrial ecology (IE) is the study of material and energy flows through industrial systems. The global industrial economy can be modelled as a network of industrial processes that extract resources from the Earth and transform those resources into products and services which can be bought and sold to meet the needs of humanity. Industrial ecology seeks to quantify the material flows and document the industrial processes that make modern society function. Industrial ecologists are often concerned with the impacts that industrial activities have on the environment, with use of the planet's supply of natural resources, and with problems of waste disposal. Industrial ecology is a young but growing multidisciplinary field of research which combines aspects of engineering, economics, sociology, toxicology and the natural sciences.
Alfred James Lotka was an American mathematician, physical chemist, and statistician, famous for his work in population dynamics and energetics. A biophysicist, Lotka is best known for his proposal of the predator–prey model, developed simultaneously but independently of Vito Volterra. The Lotka–Volterra model is still the basis of many models used in the analysis of population dynamics in ecology.
Eugene Pleasants Odum was an American biologist at the University of Georgia known for his pioneering work on ecosystem ecology. He and his brother Howard T. Odum wrote the popular ecology textbook, Fundamentals of Ecology (1953). The Odum School of Ecology is named in his honor.
Howard Thomas Odum, usually cited as H. T. Odum, 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.
Applied ecology is a sub-field within ecology that considers the application of the science of ecology to real-world questions. It is also described as a scientific field that focuses on the application of concepts, theories, models, or methods of fundamental ecology to environmental problems.
Ecology is a new science and considered as an important branch of biological science, having only become prominent during the second half of the 20th century. Ecological thought is derivative of established currents in philosophy, particularly from ethics and politics.
Ecological engineering uses ecology and engineering to predict, design, construct or restore, and manage ecosystems that integrate "human society with its natural environment for the benefit of both".
Ecosystem ecology is the integrated study of living (biotic) and non-living (abiotic) components of ecosystems and their interactions within an ecosystem framework. This science examines how ecosystems work and relates this to their components such as chemicals, bedrock, soil, plants, and animals.
Emergy is the amount of energy consumed in direct and indirect transformations to make a product or service. Emergy is a measure of quality differences between different forms of energy. Emergy is an expression of all the energy used in the work processes that generate a product or service in units of one type of energy. Emergy is measured in units of emjoules, a unit referring to the available energy consumed in transformations. Emergy accounts for different forms of energy and resources Each form is generated by transformation processes in nature and each has a different ability to support work in natural and in human systems. The recognition of these quality differences is a key concept.
The energy systems language, also referred to as energese, or energy circuit language, or generic systems symbols, is a modelling language used for composing energy flow diagrams in the field of systems ecology. It was developed by Howard T. Odum and colleagues in the 1950s during studies of the tropical forests funded by the United States Atomic Energy Commission.
In 1996 H.T. Odum defined transformity as,
"the emergy of one type required to make a unit of energy of another type. For example, since 3 coal emjoules (cej) of coal and 1 cej of services are required to generate 1 J of electricity, the coal transformity of electricity is 4 cej/J"
The environmental humanities is an interdisciplinary area of research, drawing on the many environmental sub-disciplines that have emerged in the humanities over the past several decades, in particular environmental literature, environmental philosophy, environmental history, science and technology studies, environmental anthropology, and environmental communication. Environmental humanities employs humanistic questions about meaning, culture, values, ethics, and responsibilities to address pressing environmental problems. The environmental humanities aim to help bridge traditional divides between the sciences and the humanities, as well as between Western, Eastern, and Indigenous ways of relating to the natural world and the place of humans within it. The field also resists the traditional divide between "nature" and "culture," showing how many "environmental" issues have always been entangled in human questions of justice, labor, and politics. Environmental humanities is also a way of synthesizing methods from different fields to create new ways of thinking through environmental problems.
The maximum power principle or Lotka's principle has been proposed as the fourth principle of energetics in open system thermodynamics, where an example of an open system is a biological cell. According to Howard T. Odum, "The maximum power principle can be stated: During self-organization, system designs develop and prevail that maximize power intake, energy transformation, and those uses that reinforce production and efficiency."
An ecosystem model is an abstract, usually mathematical, representation of an ecological system, which is studied to better understand the real system.
Charles A. S. Hall is an American systems ecologist and ESF Foundation Distinguished Professor at State University of New York in the College of Environmental Science & Forestry.
Deep ecology is an environmental philosophy that promotes the inherent worth of all living beings regardless of their instrumental utility to human needs, and the restructuring of modern human societies in accordance with such ideas.
