Energy Pyramid

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An energy pyramid is the graphical representation of the trophic levels (nutritional) by which the incoming solar energy is transferred into an ecosystem. The source of energy for living beings on Earth is the Sun. The energy that the Sun emits at present is of 1366.75 W/m^2 (400 years ago, it was of 1363.48 W/m^2). When the studies of the capture of energy by the producer organisms (photosynthetic organisms) were made, the Solar Irradiance (SI) was of 1365.45 W/m^2. The energy usable by photosynthetic organisms is 697.04 W/m^2; nevertheless, the photosynthetic organisms take only 0.65 W/m^2 and the rest of the incident energy on the surface is transferred to the abiotic surroundings (oceans, soil, atmosphere, etc.) and from there, the energy is emitted to the outer space and to the Gravity field (Guth. 1999. Pp. 29-31). The atmosphere absorbs 191.345 W/m^2, maintaining the tropospheric temperature of Earth in the hospitable 35.40 °C (95.72 °F).

On the diagram, the ciphers expressed in the boxes at the left side of the pyramid represent the energy taken by each individual. For example, the amount of energy acquired by the herbivores is equivalent to the ingestion of one gram of organic material from photosynthetic organisms. Each subsequent amount of energy (green rectangle) in the pyramid (towards the peak) is the energy that would be obtained by each gram of organic material originated from the underlying level. Detritivores or detritivorous are organisms that fed on remnants of organic matter, like corpses, excrements, etc. Detritivores take advantage of ca. 57% from the energy stored by the producers.

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SECOND KIND OF ECOLOGICAL ENERGY PYRAMID

The energy pyramid below this paragraph was built in 1978 from data taken from nature. The studied ecosystem characterizes a field near Biology Cabinet's offices:

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In the scheme above these lines, the base level which corresponds to the Producers displays Net Primary Production (NPP) of 1%; nevertheless, in recent studies scientists have observed that the NPP has been increased by 1.2% in the last 23 years (Nemani et al. 2003) (Wielicki et al. 2002); as a result, the amount of energy captured by the photosynthetic organisms is 25776.8 Kcal/m^2 per year; that is an increase in the NPP of 305.6532 Kcal/m^2 per year. This gives a demonstration of how a small increase of the incident solar irradiation on the biosphere can lead to enormous beneficial increase in the energy available in the food chain.

The aforementioned studies demonstrate that the cause of the increase of NPP is the climate change derived from small increases in the intensity of solar radiation penetrating the atmosphere in its way onto the biosphere. (Nemani et al. 2003) (Wielicki et al. 2002).

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REFERENCES AND BIBLIOGRAPHY

Bruce A. Wielicki, Takmeng Wong, Richard P. Allan, Anthony Slingo, Jeffrey T. Kiehl, Brian J. Soden, C. T. Gordon, Alvin J. Miller, Shi-Keng Yang, David A. Randall, Franklin Robertson, Joel Susskind, Herbert Jacobowitz. Evidence for Large Decadal Variability in the Tropical Mean Radiative Energy Budget. Science, 1 February 2002: Vol. 295. No. 5556, pp. 841 - 844. DOI: 10.1126/science.1065837

Curtis, Helen. Biology. 1983. Worth Publishers, Inc., New York, New York.

Guth, Alan H. The Inflationary Universe: The Quest for a New Theory of Cosmic Origins. Perseus Books Group, 1999, New York, New York. Pp. 29-31.

Odum, Eugene P. and Barrel, Gary W. Fundamentos de Ecología-Quinta Edición.2006. International Thompson Editores, S. A. de C. V. México, Distrito Federal.

Ramakrishna R. Nemani, Charles D. Keeling, Hirofumi Hashimoto, William M. Jolly, Stephen C. Piper, Compton J. Tucker, Ranga B. Myneni, Steven W. Running. Climate-Driven Increases in Global Terrestrial Net Primary Production from 1982 to 1999. Science 6 June 2003: Vol. 300. No. 5625, pp. 1560 - 1563. DOI: 10.1126/science.1082750.

Sutton, David B., Harmon, N. Paul. Ecology: Selected Concepts. 2000. John Wiley & Sons, Inc. New York.

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