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Howard T. Odum

Systems Ecology
20th century
Name: Howard Thomas Odum
Birth: 1 September 1924
Chapel Hill, North Carolina, USA
Death: 11 September 2002
Gainesville, Florida, USA
School/tradition: Zoology
Main interests: Mathematics, Ecology and Natural philosophy
Notable ideas: Ecological economics, ecological engineering, Emergy, Maximum power principle, Systems ecology

Howard Thomas Odum (1924–2002), known as H.T. Odum, Tom Odum or just H.T., was an American ecologist and a professor at the University of Florida. He is known for his pioneering work on ecosystem ecology together with his brother Eugene Odum, but also for his provocative proposals for additional laws of thermodynamics, proposals which were informed by his work within general systems theory.



Howard Thomas Odum was born in 1924 in Chapel Hill in North Carolina as third child, following his brother Eugene and sister Mary Francis. Their father was the influential American sociologist Howard W. Odum. His father encouraged his sons to go into science and to develop new techniques to contribute to social progress. Howard learned his early scientific lessons about birds from his brother, about fish and the philosophy of biology while working after school for the marine zoologist Robert Coker, and about electrical circuits from "The Boy Electrician. [1].

Howard Thomas studied zoology at the University of North Carolina at Chapel Hill. With his early interest in ornithology and electronic circuits, he published his first paper while he was still an undergraduate. His education was interrupted for three years by his wartime service with the Army Air Force in Puerto Rico and the Panama Canal Zone where he worked as a tropical meteorologist. Back at the University of North Carolina, he earned his B.S. in zoology (Phi Beta Kappa) in 1947.

In 1947 Howard T. Odum married Virginia Wood in Virginia, who died in 1973. In 1974 H.T. remarried Elizabeth C. Odum. He had two children from his previous marriage, and E.C. Odum had four from hers. H.T.Odum's advice on how to manage a blended family was to be sure to keep talking, while E.C.Odum's was to hold back on discipline and new rules.[2]

In 1950 Howard earned his Ph.D. in zoology at Yale University, 1950 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 analysis of the global circulation of strontium, anticipated in the late 1940s the now-accepted view of the earth as one great ecosystem. [3]

Before the end of Howard’s studies at Yale his collaborations with his brother Eugene began. At that time, they started the first English-language textbook on systems ecology, Fundamentals of Ecology, which was published in 1953 and had very broad influence. H.T. Odum wrote the chapter on energetics which introduced his energy circuit language. Their collaborations after that, in research as well as writing, were frequent. Moreover for H.T.Odum, his energese or energy systems language was itself a collaborative tool. [4]

  From 1956 to 1963 H.T. Odum worked as Director of the Marine Institute of the University of Texas. During this time Odum became aware of the interplay of ecological-energetic and economic forces. Back in Florida H.T. Odum taught at the Center for Environmental Policy at the University of Florida for roughly thirty years and founded the University's Center for Wetlands in 1973, the first of its kind in the world. In the 1960's-1970's Odum was also chairman of the International Biological Program's Tropical Biome planning committee and was supported by large contracts with the United States Atomic Energy Commission with nearly 100 scientists, which involved radiation studies of a tropical rainforest [5]

By the end of his life, H.T. Odum was Graduate Research Professor Emeritus and Director of the Center for Environmental Policy.[6] He was also known as an avid birdwatcher in both his professional and personal life.

In recognition of Odum's contributions, he was awarded the Mercer Award of the Ecological Society for the study of the coral reef on Eniwetok Atoll [7], the French Prix de Vie, and the Crafoord Prize of the Royal Swedish Academy of Science considered the Nobel equivalent for bioscience not originally honored by Nobel himself. Charles A S Hall has called Odum one of the most innovative and important thinkers of our time.[8] According to Hall, Howard T. Odum alone or with his brother Eugene had received essentially all of the most prestigious awards available to an ecologist.

H.T. Odum's students have carried on his work at institutions around the world, most notably the University of Florida with Dr. Mark Brown, the University of Maryland with Dr. David Tilley and Dr. Patrick Kangas, the United States EPA with Dr. Daniel Campbell, UNICAMP in Brazil overseen by Dr. Enrique Ortega, and the University of Siena with Dr. Sergio Ulgiati. These institutions continue to evolve and propagate the emergy concept.

His contributions to this field have been recognised by the Mars Society who named their experimental station the "H.T.Odum greenhouse". The greenhouse was dedicated to H.T. Odum at the suggestion professor Patrick Kangas (University of Maryland). Professor Kangas and his graduate student, David Blersch both made significant contributions to the waste water recycling system design.

Work: An overview

H.T. Odum studied ecosystems all over the world. He pioneered the study of several areas, some of which have as a result become distinct fields of research. Hall (1995, p.ix) said there are now at least six scientific areas in which Odum published one of the first significant papers:

  • Ecological modeling (deriving from Odum 1960a),
  • Ecological engineering (deriving from Odum et al. 1963),
  • Ecological economics (deriving from Odum 1971),
  • Estuarine ecology (deriving in part from Odum and Hoskins 1958 and others),
  • Tropical ecosystems ecology (deriving from Odum and Pidgeon 1970),
  • General systems theory

Odum left a large scientific legacy in many fields associated with ecology, systems and energetics. [9]. Odum also made significant contributions to the fields of radiation ecology, systems ecology, unified science, and microcosm research. He was one of the first people to discuss the use of ecosystems for life-support function in space travel.[10] Some authors have suggested that Odum was technocratic in orientation [11] while others have suggested that he is on the "new values are needed" side.

This article will further look at his major contributions to the fields of ecological modeling, energetics, systems ecology, ecological economics, ecological engineering and general systems theory.

Ecological modeling

A new integrative approach in ecology

In his Ph.D. thesis in 1950, H.T.Odum gave a novel definition of ecology as the study of large entities (ecosystems) at the "natural level of integration" [12]. Hence, in the traditional role of an ecologist, one of Odum's doctoral aims was to recognise and classify large cyclic entities (ecosystems). However another of his aims was to make predictive generalizations about ecosystems, such as the whole world for example. For Odum, as a large entity, the world constituted a revolving cycle with high stability. It was the presence of stability which, Odum believed, enabled him to talk about the teleology of such systems. Moreover, at the time of writing his thesis, Odum felt that the principle of natural selection was more than empirical, because it had a teleological, that is a "stability over time" component. And as an ecologist interested in the behaviour and function of large entities over time, Odum therefore sought to give a more general statement of natural selection so that it was equally applicable to large entities as it was to small entities traditionally studied in biology: [13]

Hence Odum also had the aim of extending the scope and generality of natural selection, to include large entities such as the world. This extension relied on the definition of an entity as a combination of properties that have some stability with time [14][15]

Ecosystem simulation

In writing a history of the ecosystem concept, Golley noted that Odum tended to think in the form of analogies, and gave the example, "if the world is a heat engine, then..." In this vein, Odum can be understood as extending the dynamical analogies which establish the analogies between electrical, mechanical, acoustical, magnetic and electronic systems, to include ecological systems.[16]

Odum used an analog of electrical energy networks to model the energy flow pathways of ecosystems.[17] Odum's analog electrical models had a significant role in the development of his approach to systems and have been recognized as one of the earliest instances of systems ecology. [18]

Electron flow in the electrical network represented the flow of material (e.g. carbon) in the ecosystem, charge in a capacitor was analogous to storage of a material, and the model was scaled to the ecosystem of interest by adjusting the size of electrical component.[19]

Ecological analog of Ohm's Law

In the 1950s Odum introduced his electrical circuit diagrams of ecosystems to the Ecological Society of America. He claimed that energy was driven through ecological systems by an "ecoforce" analogous to the role of voltage in electrical circuits.[20]

Odum developed an analogue of Ohm's Law which aimed to be a representation of energy flows through ecosystems.[21] In terms of steady state thermodynamics, Ohm's Law can be considered a special case of a more general flux law, where the flux (J) "is proportional to the driving thermodynamic flux (X) with conductivity (C). That is: J = CX.[22]

Kangas states that Odum then also concluded that as thermodynamic systems, ecosystems should also obey the force-flux law [23]. Hence Ohm's law and passive electrical analog circuits can be used to simulate ecosystems (Ibid.). In this simulation, Odum attempted to derive an ecological analog for electrical voltage. Voltage, or driving force, is related to something we have measured for years, the biomass, in pounds per acre. The analogous concept required is the biomass activity, that is, the thermodynamic thrust, which may be linear. Exactly what this is in nature is still uncertain, as it is a new concept.

Such a consideration led Odum to ask two important methodological questions: 1) What is the electrical significance of a function observed in nature? 2) Given an electrical unit in a circuit, what is it in the ecological system? For example, what is a diode in nature? One needs a diode to allow biomass to accumulate after the voltage of the sun has gone down. Otherwise the circuit reverses. Higher organisms like fish are diodes.

The Silver Spring study

Silver Spring is a common type of spring-fed lake in Florida, with a constant temperature and chemical composition. The study Howard Odum conducted here was the first complete analysis of a natural ecosystem.[3]   Odum started with an overall model. In this model energy and matter flows through an ecosystem: [24] H are herbivores, C are carnivores, TC are top carnivores, and D are decomposers. Squares represent biotic pools and ovals are fluxes or energy or nutrients from the system.

Odum mapped in detail all the flow routes to and from the lake. He measured the energy input of sun and rain, and of all organic matter - even those of the bread the tourists threw to the ducks and fish - and then measured that gradually left the lake. In this way he was able to establish the lake's energy budget.[3]


Main article: Energetics

Ecological and biological energetics

Around 1955 Odum directed studies into radioecology [25] which included the effects of radiation on the tropical rainforest at El Verde, Puerto Rico (Odum and Pidgeon), and the coral reefs and ocean ecology at Eniwetok atoll.[26] The Odum brothers were approached by the Atomic Energy Commission to undertake a detailed study of the atoll after nuclear testing. Apparently the atoll was sufficiently radioactive that upon their arrival the Odums were able to produce an autoradiographic image of a coral head by placing it on photographic paper.[27] These studies were early applications of energy concepts to ecological systems. They were exploring the implications of the laws of thermodynamics when used in these new settings.[28]

From this view, biogeochemical cycles are driven by radiant energy.[29] Odum expressed the balance between energy input and output as the ratio of production (P) to respiration (R): P-R. He classified water bodies based on their P-R ratios, this separated autotrophic from heterotrophic ecosystems: "his measurements of flowing water metabolism were measurements of whole systems. Odum was measuring the community as a system, not adding up the metabolism of the components as Lindeman and man others had done".[30] This reasoning appears to have followed that of Odum's doctoral supervisor, G.E.Hutchinson who expressed the view that if a community were an organism then it must have a form of metabolism [31] However Golley notes that H.T.Odum attempted to go beyond the reporting of mere ratios, a move which resulted in the first serious disagreement in systems energetics.

Maximum power theory and the proposal for additional laws of thermodynamics/energetics

In a controversial move, Odum, together with Richard Pinkerton (at the time physicist at the University of Florida), was motivated by Lotka's articles on the energetics of evolution, and subsequently proposed that the theory that natural systems tend to operate at an efficiency that produces the maximum power output, not the maximum efficiency. [32] This theory in turn motivated Odum to propose maximum power as a fundamental thermodynamic law. Further to this Odum also mooted two more additional thermodynamic laws (see Energetics), but there is far from consensus in the scientific community about these proposals, and many scientists have never heard of H.T.Odum or his views.

Energese: Energy Systems Language

By the end of the 1960s Odum's electronic circuit ecological simulation models were replaced by a more general set of energy symbols. When combined to form systems diagrams, these symbols were considered by Odum and others to be the language of the macroscope which could portray generalized patterns of energy flow: "Describing such patterns and reducing ecosystem complexities to flows of energy, Odum believed, would permit discovery of general ecosystem principles".[33] Some have attempted to link it with the universal scientific language projects which have appeared throughout the history of natural philosophy [34][35]


Kitching claimed that the language was a direct result of working with analogue computers, and reflected an electrical engineer's approach to the problem of system representation: "Because of its electrical analogy, the Odum system is relatively easy to turn into mathematical equations ... If one is building a model of energy flow then certainly the Odum system should be given serious consideration... "[36]

Energy quality

In taking an energy-based view of hierarchical organization also developed further the systems ecology understanding of energy quality.


Main article: Emergy

In the 1990s in the latter part of his career H.T. Odum together with David M. Scienceman developed the ideas of emergy, as a specific use of the term Embodied energy. Some consider the concept of "emergy", sometimes briefly defined as "energy memory", as one of Odum's more significant contributions. However the concept is neither free from controversy, and not without its critics. Odum looked at natural systems as having been formed by the use of various forms of energy in the past: "emergy is a measure of energy used in the past and thus is different from a measure of energy now. The unit of emergy (past available energy use) is the emjoule to distinguish it from joules used for available energy remaining now." This was then conceived as a principle of maximum empower which might explain the evolution of self-organising open systems. However such a principle has not been empirically demonstrated nor verified by the scientific community.

Ecosystem ecology and systems ecology

Main articles: Ecosystem ecology and systems ecology

For Hagen, the maximum power principle, and the stability principle could be easily translated into the language of homeostasis and cybernetics systems [37] Hagen claims that the feedback loops in ecosystems, were, for Odum, analogous to the kinds of feedback loops diagrammed in electronic circuits and cybernetic systems (Ibid.). This approach represented the migration of cybernetic ideas into ecology and led to the formulation of systems ecology. In Odum's work these concepts form part of what Hagen called an, "ambitious and idiosyncratic attempt to create a universal science of systems" (Ibid).

The ecosystem concept

Main article: ecosystem


Hagen has identified the systems thinking of Odum as a form of holistic thinking.[38] Odum contrasted the holistic thinking of systems science with reductionistic microscopic thinking, and used the term "macroscope" to refer to the holistic view, which was a kind of "detail eliminator" allowing a simple diagram to be created.[39]


H.T.Odum was a pioneer in his use of small closed and open ecosystems in classroom teaching. These small ecosystems were often constructed from fish tanks or bottles and have been called microcosms.[40] Odum's microcosm studies influenced the design of Biosphere 2 [41]

Hierarchical organization

In observing the way higher order trophic levels have a control function in ecosystems H.T.Odum arrived at the concept he termed hierarchical organization.

Ecological economics

Main article: Ecological economics

Ecological economics is now an active field between economics and ecology with annual conferences, international societies and an international journal. From 1956 to 1963 H.T.Odum worked as Director of the Marine Institute of the University of Texas. During this time Odum became aware of the interplay of ecological-energetic and economic forces. He therefore funded the research into the use of conventional economic approaches to quantify dollar values of ecological resources for recreational, treatment and other uses. This research calculated the potential value of primary production per bay surface area [42]

For Hall [43] the importance of Odum's work came through his integration of systems, ecology, and energy with economics, together with Odum's view that economics can be evaluated on objective terms such as energy rather than on a subjective, willingness to pay basis.

Ecological engineering

Main article: Ecological engineering

Ecological Engineering is an emerging field of study between ecology and engineering concerned with the designing, monitoring and constructing of ecosystems. The term ecological engineering was first coined by the Howard T. Odum in 1962 [44] when he worked at the University of Florida. Ecological engineering, he wrote, is "those cases where the energy supplied by man is small relative to the natural sources but sufficient to produce large effects in the resulting patterns and processes." [45]

General systems theory

Main article: Systems theory

Odum has been described as a "technocratic optimist".[46] His approach was significantly influenced by his father who was also an advocate of viewing the social world through the various lenses of physical science.[47] Within the processes on earth, H.T.Odum (1989) viewed humans as playing a central role: He said that the "human is the biosphere's programmatic and pragmatic information processor for maximum performance".

... Integration of science and society ...??


H.T. Odum wrote some 15 books and 300 papers, and a Festschrift volume (Maximum Power: The Ideas and Applications of H.T.Odum 1995) was published in honour of his work. [48]


  • 2001, A Prosperous Way Down: Principles and Policies, with Elisabeth C. Odum, University Press of Colorado.
  • 2000, with E.C. Odum, Modeling for all Scales: An introduction to System Simulation, Academic Press.
  • 1999, Heavy Metals in the Environment: Using Wetlands for Their Removal.
  • 1999, Biosphere 2 : Research, Past and Present, with Bruno D. V. Marino.
  • 1996, Environmental Accounting: EMERGY and environmental decision making.
  • 1993, Ecological Microcosms, with Michael J. Beyers.
  • 1984, Cypress Swamps with Katherine C. Ewel.
  • 1983, Systems Ecology : an Introduction.
  • 1981, Energy Basis for Man and Nature, with Elisabeth C. Odum.
  • 1970, with Robert F. Pigeon (eds), A Tropical Rain Forest; a Study of Irradiation and Ecology at El Verde, Puerto Rico, United States Atomic Energy Commission, National Technical information service.
  • 1971, Environment, Power and Society, 1971
  • 1967, (ed.) Work Circuits and System Stress, in Young, Symposium on Primary Productivity and Mineral Cycling, Universit of Maine Press.
  • 1953, 'Fundamentals of Ecology, with Eugene P. Odum, (first edition).

Articles (selection)

  • 1998, eMergy Evaluation, paper presented at the International Workshop on Advances in Energy Studies: Energy flows in ecology and economy, Porto Venere, Italy, May 27.
  • 1989, Comments and thanks to Students and Associates, Handout on the Occasion of the Celebration in Chapel Hill, N.C, in: "Advances in Understanding Ecological Systems", August 31-September, 2.
  • 1977, The ecosystem, energy, and human values, in: Zygon, Volume 12 Issue 2 Page 109-133.
  • 1973, Energy, ecology and economics, Royal Swedish Academy of Science. in: AMBIO, 2 (6), 220-227.
  • 1963, with W.L. Slier, R.J. Beyers & N. Armstrong, Experiments with engineering of marine ecosystems, in: Publ. Inst. Marine Sci. Univ. Tex. 9:374-403.
  • 1963, Limits of remote ecosystems containing man, in: The American Biology Teacher. 25 (6): 429-443.
  • 1960a, Ecological potential and analog circuits for the ecosystem, in: Amer. Sci. 48:1-8.
  • 1960b, Ten classroom sessions in ecology in: The American Biology Teacher. 22 (2): 71-78.
  • 1958, with C.M. Hoskin, Comparative studies of the metabolism of Texas bays, in: Publ. Inst. Mar. Sci., Univ. tex., 5:16-46.
  • 1955, with E.P. Odum, Trophic structure and productivity of a winward coral reef community on Eniwetok Atoll, in: Ecological Monographs. 35, 291-320.
  • 1950, The Biogeochemistry of Strontium: With Discussion on the Ecological Integration of Elements, A Dissertation presented to the Faculty of the Graduate School of Yale University in Candidacy for the Degree of Doctor of Philosophy.

About Howard T. Odum

  • Beyers, R.J. 1964. The Microcosm Approach to Ecosystem Biology. The American Biology Teacher. 26 (7): 491-498.
  • Bocking, S. 1997. Ecologists and environmental politics: a history of contemporary ecology, Yale University.
  • Cevolatti, D., and Maud, S., 2004, "Realising the Enlightenment: H. T. Odum's Energy Systems Language qua G. W. v. Leibniz's Characteristica Universalis," Ecological Modelling 178: 279-92.
  • Costanza, R. 1997. An Introduction to Ecological Economics, CRC Press.
  • Ewel, John J. 2003. Resolution of Respect: Howard Thomas Odum Bulletin of the Ecological Society of America. January 2003: 12-15 (PDF)
  • Gilliland, M.W. ed. (1978) Energy Analysis: A New Public Policy Tool, AAA Selected Symposia Series, Westview Press, Boulder, Colorado.
  • Golley, F. 1993. A History of the Ecosystem Concept in Ecology: More than the sum of the parts, Yale University Press.
  • Hagen, J.B. 1992. An Entangled Bank: The Origins of Ecosystem Ecology. Rutgers University Press.
  • Hall, C.A.S. (ed.) 1995. Maximum Power: The Ideas and applications of H.T.Odum. Colorado University Press.
  • Debora Hammond, 1997. Ecology and Ideology in the General Systems Community, Environment and History, Volume 3, Number 2, pp. 197-207(11)
  • Hammond, G. 2007. Energy and sustainability in a complex world: Reflections on the ideas of Howard T. Odum, Int. J. Energy Res. (in press).
  • Kangas, P. 1995. Contributions of H.T.Odum to Ecosystem Simulation Modelling, in Hall (ed.) Maximum Power: the Ideas and Applications of H.T.Odum, Colorado University Press, Colorado.
  • Kangas P. 2004. The role of passive electrical analogs in H.T. Odum's systems thinking, Ecological Modelling, v 178 (1-2), 101-106.
  • Kangas P. 2004b. Ecological economics began on the Texas bays during the 1950s, Ecological Modelling, v 178 (1-2), 179-181.
  • Kitching R.L. 1983. Systems Ecology: An Introduction to Ecological Modelling, University of Queensland Press.
  • Lugo, A. E. 1995. A review of Dr. Howard T. Odum's early publications: From bird migration studies to scott nixon's turtle crass model. In Hall (ed.) Maximum Power: The Ideas and applications of H.T.Odum. Colorado University Press.
  • Madison, M.G. 1997. 'Potatoes Made of Oil': Eugene and Howard Odum and the Origins and Limits of American Agroecology, Environment and History, Volume 3, Number 2, June 1997, pp. 209-238 (30
  • Odum, E.C. 1995. H.T. Odum as a Husband and Colleague, in Hall (ed.), Maximum Power: The Ideas and applications of H.T. Odum. Colorado University Press, pp.360-361.
  • Taylor, Peter J. 1988. Technocratic optimism, H.T. Odum and the partial transformation of ecological metaphor after World War 2. Journal of the History of Biology 21:213-244.


  1. ^ Taylor 1988, p.223.
  2. ^ (E.C.Odum 1995, p. 360).
  3. ^ a b c The Craford prize 1987 for Eugene P. Odum and Howard T. Odum, with an overview of H.T. Odum's career, 23 September 1987.
  4. ^ H.T. Odum told, that "when a group gathers around a table to talk about analyzing the main components of a new system or problem, one person can diagram for the group, enhancing the coherence of the dicusssion. If the symbols are understood by all, the process of discussion and drawing unites people and thinking around a task with a minimum of semantic problems about meanings. A group, collective-thinking exercise stimulates memories and draws out qualitative and quantitative knowledge from combined experiences with the real-world system of concern. This can be an effective problem-solving and analysis activity in management, research, and classroom settings and should be attempted as a learning tool. It is a useful first step before quantitative or simulation studies." (Howard T. Odum 1994, p.21.)
    Note: Recently Raphael Valyi coded a java tool which aims in part to provide a globalised facility for collaborative diagraming, and simulating of systems using Odum's energy systems language.
  5. ^ Odum & Pigdon, A Tropical Rainforest
    According to Hagen (1992, p. 168) the then director of the Environmental Sciences Division at the United States A.E.C., John Wolfe, considered Odum's study to be one of the best ever funded by the U.S. A.E.C.
  6. ^ In a handout to thank students and associates H.T.Odum (1989, p.1) described his role as follows: I have played many roles sometimes with the majority, but more often attempting to shock the scientific establishment into a better view.
  7. ^ (Hagen 1992, p.101)
  8. ^ Charles A S Hall, 1995, p.ix
  9. ^ Costanza (1996, p. 61) wrote: "Odum's work on energy flow through systems and dynamic modelling of systems spawned, or at least paralleled and encouraged, an immense amount of work by his students and others ranging from input-output studies of energy and material flow in ecological and economic systems ... to dynamic simulation models of whole ecosystems and integrated ecological economic systems."
  10. ^ Hall comments that many of "H.T.'s" old ideas have been given new wrappings by academics unaware of their roots in the work of H.T.Odum. Hall (1995, p.1) said: I remember in 1967 H.T. telling me that some day industrial nations would have to be subsidizing the growing of tropical forests to sequester CO2, something that in fact has come to pass on at least a small scale. Thus a lot of his ideas that seemed so improbable in the past are considered common knowledge now.
  11. ^ Talyor 1988, Hammond 1997.
  12. ^ H.T. Odum, 1950, p.3.
  13. ^ H.T. Odum (1950 pp.7, 10-11) said: A more general statement is that "a system which has stability with time will exist longer than a system without stability".
    ... "Nature seeks steady state entities by natural selection" Of course natural selection in biological systems is a special case of this principle.
    ... Le Chatelier's principle from this view point may be phrased that a system with a self correcting mechanism has reached this condition by natural selection.
    ... The second law of thermodynamics appears to be another special case. A system with constant temperature is selected by nature as more stable than a system with different temperatures together.
  14. ^ H.T. Odum (1950, pp.6, 8) said: It is now proposed to extend natural selection to the natural level of integration and to the large ecological entities which include both biological and inorganic components. It is postulated that there is a natural selection of the possible systems that may form from a given starting condition, and that those systems that result are those which have mechanisms of maintaining stability. It is thus postulated that natural selection of natural systems results in the formation of entities defined as above. The reason that systems can not proceed toward some kind of disintegration is that such a pattern has no mechanism of maintaining itself. As soon as it does the system fits the definition of an entity.
  15. ^ Odum then went on to explore the consequence of applying such a view (1950, p.9): If this postulate is applied to all of nature, the resulting proposition is that nature is as a whole in a steady state or is in the most stable form possible and constitutes one big entity. This does not necessarliy contradict evolutionary changes in the earth's history since these changes may be part of a larger steady state systems.
  16. ^ Odum stated: In trying to solve the ecosystem, one compares it to an electrical system, for which the synthetic knowledge is much greater, and also one attempts to generalize more or less in the way of steady-state thermodynamics.
  17. ^ (Golley, p. 189)
  18. ^ Kangas (2004, p.101) said: In the 1950s and the 1960s H.T.Odum used simple electrical networks composed of batteries, wires, resistors and capacitors as models for ecological systems. These circuits were called passive analogs to differentiate them from operational analog computer circuits, which simulated systems in a different manner.
  19. ^ Kangas 2004, p.102.
  20. ^ Hagen (1992, p.144): This, according to Odum, necessitated a fundamental change in the way ecologists thought about predator-prey relationships. "The validity of this application [[[Ohm's Law]] ] may be recognized", he asserted, "when one breaks away from the habit of thinking that a fish or a bear catches food and thinks instead that accumulated food by its concentration practically forces food through the consumers."
  21. ^ (Golley 1993, p.95)
  22. ^ Ibid., Kangas 1995, pp.11-12). Kangas noted that Odum first set out the theory that Ohm's Law from electronics was analogous to the thermodynamic functioning of ecosystems (2004, p.101): It seems clear that for Odum the concept that a battery (or more explicitly the solar electricity generator he sometimes used) pushed electrons around a copper circuit in almost exactly the same way that the sun pushed energy (or reduced carbon) around the invisible circuits of an ecosystem.
  23. ^ (Kangas 1995, p.12)
  24. ^ The picture is adapted from the Silver Springs model; Odum 1971)
  25. ^ (Golley 1993, p.74)
  26. ^ (Odum and Odum 1955)
  27. ^ (Hagen 1992, p.102)
  28. ^ Golley (1993, pp.70, 82) said: Odum pioneered a method of studying system dynamics by measuring the chemistry of the input and output water. The difference between input and output, under steady state conditions, was a measure of the metabolism of the whole system. Tom Odum ... was motivated to study the whole system as a unit. His general plan "was to characterize the chemostatic flow, to establish the qualitative and quantitative community structure, to measure the production rates, and to study the mechanisms by which the community metabolism is self-regulated".
  29. ^ Taylor 1988, p. 226.
  30. ^ Golley 1993, pp.83, 93.
  31. ^ Hagen 1992, p.50.
  32. ^ Odum and Pinkerton 1955. This was described variously as the "maximum power principle" (Odum 1994), "maximum power theory" (Gilliland 1978), "maximum power efficiency" (Costanza 1999, p.60), "optimum efficiency maximum power principle" (Odum 1970), and "maximum power output theorem" (Golley 1993, p. 87).
  33. ^ (Bocking 1997, p.73)
  34. ^ Cevolatti and Maud 2004.
  35. ^ This language has gone by several names including, "energy circuit language" (Odum 1971), "Energy Systems Language" (Odum and Odum 2000), "universal energy language" (Hagen 1992, p.135), and "Energese" (Hagen 1992, p.135): Odum believed that this language could be applied to any system: electrical, mechanical, biological, or social. This ambitious program in systems ecology was summarized in Odum's semipopular book, Environment, Power, and Society ... intended to explain basic concepts of ecology using Odum's energy language. ... It presented a cogent argument for the limits of industrial growth. Circuit diagrams were skillfully used to illustrate the dependence of agricultural ecosystems and industrial societies upon fossil fuel subsidies ... Voting, public opinion, taxes, even revolution and war could be expressed in the language of energy circuits.
  36. ^ Kitching 1988, p.25.
  37. ^ (Hagen 1992, pp.130, 131).
  38. ^ Hagen 1992, p.138.
  39. ^ Madison (1997, p.215): The intricate biological details of a particular ecosytem were relevant; natural history serves as an important means of creating an "inventory of the parts" for the system, but the real explanation came in terms of overall energy flow through the ecosystem as a whole. For example, when the Odums had studied the metabolism of the reef at Eniwetok Atoll, they were not concerned with individual species. Indeed, at the time they were unable to identify them. Nonetheless, they were able to estimate the total flow of energy through the entire system. Had they started studying the reef from the bottom up, they might never have gotten around to studying its overall metabolism.
  40. ^ Beyers 1964.
  41. ^ 1999 Biosphere 2 : Research, Past and Present, with Bruno D. V. Marino.
  42. ^ Kangas (2004b, p.179-180): Odum was involved to a greater or lesser extent in the first calculation of the value of an ecosystem service in 1958! ... He divided fossil fuel use by GNP at the national scale to estimate a ratio of 10,000 Cal/$. By dividing this conversion into ecological energy flow he calculated what he termed life support value. ... Much interesting ecological economics work grew from Odum's life support calculations. The important dialog about the value of salt marsh wetlands ... can be traced back to these early calculations as can, to some extent, the whole notion of ecosystem services so popular today among ecological economists...
  43. ^ Hall 1995, p. 159.
  44. ^ David Del Porto
  45. ^ H.T. Odum, 1962
  46. ^ Taylor 1988, Lugo 1995.
  47. ^ Hagen (1992, p.135): The energetics laws are as much first principles of political science as they are first principles of any other process on earth.
  48. ^ In a review of Maximum Power, Robert V. O'Neill (1996, p.2263) of the Oak Ridge National Laboratory wrote: What is clear is that H.T.Odum [was] a genius and an integrative genius seldom books petty constraints.


  • Center for Environmental Policy
  • (H.T. Odum) Center for Wetlands
  • Photo archive and H.T. Odum collection in the Encyclopedia of Earth
  • H.T. Odum Cypress Dome Wetland
  • Photo of the inside of the Mars Society's H.T. Odum Greenhouse
  • Photo of the outside of the Mars Society's H.T. Odum Greenhouse
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Howard_T._Odum". A list of authors is available in Wikipedia.
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