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  2. Ecological efficiency - Wikipedia

    en.wikipedia.org/wiki/Ecological_efficiency

    Out of a total of 28,400 terawatt-hours (96.8 × 10 ^ 15 BTU) of energy used in the US in 1999, 10.5% was used in food production, [3] with the percentage accounting for food from both producer and primary consumer trophic levels. In comparing the cultivation of animals versus plants, there is a clear difference in magnitude of energy efficiency.

  3. Ecological pyramid - Wikipedia

    en.wikipedia.org/wiki/Ecological_pyramid

    Ecological pyramid. A pyramid of energy represents how much energy, initially from the sun, is retained or stored in the form of new biomass at each trophic level in an ecosystem. Typically, about 10% of the energy is transferred from one trophic level to the next, thus preventing a large number of trophic levels.

  4. First law of thermodynamics - Wikipedia

    en.wikipedia.org/wiki/First_law_of_thermodynamics

    e. The first law of thermodynamics is a formulation of the law of conservation of energy in the context of thermodynamic processes. The law distinguishes two principal forms of energy transfer, heat and thermodynamic work, that modify a thermodynamic system containing a constant amount of matter. The law also defines the internal energy of a ...

  5. Exponential growth - Wikipedia

    en.wikipedia.org/wiki/Exponential_growth

    Exponential growth is a process that increases quantity over time at an ever-increasing rate. It occurs when the instantaneous rate of change (that is, the derivative) of a quantity with respect to time is proportional to the quantity itself. Described as a function, a quantity undergoing exponential growth is an exponential function of time ...

  6. Energy flow (ecology) - Wikipedia

    en.wikipedia.org/wiki/Energy_flow_(ecology)

    Energy flow (ecology) A food pyramid and a corresponding food web, demonstrating some of the simpler patterns in a food web. A graphic representation of energy transfer between trophic layers in an ecosystem. Energy flow is the flow of energy through living things within an ecosystem. [ 1] All living organisms can be organized into producers ...

  7. Aufbau principle - Wikipedia

    en.wikipedia.org/wiki/Aufbau_principle

    e. In atomic physics and quantum chemistry, the Aufbau principle ( / ˈaʊfbaʊ /, from German: Aufbauprinzip, lit. ' building-up principle '), also called the Aufbau rule, states that in the ground state of an atom or ion, electrons first fill subshells of the lowest available energy, then fill subshells of higher energy.

  8. Biomass (ecology) - Wikipedia

    en.wikipedia.org/wiki/Biomass_(ecology)

    A biomass pyramid shows the amount of biomass at each trophic level. A productivity pyramid shows the production or turn-over in biomass at each trophic level. An ecological pyramid provides a snapshot in time of an ecological community. The bottom of the pyramid represents the primary producers . The primary producers take energy from the ...

  9. Fine-structure constant - Wikipedia

    en.wikipedia.org/wiki/Fine-structure_constant

    A nondimensionalised system commonly used in high energy physics sets ε 0 = c = ħ = 1, where the expressions for the fine-structure constant becomes [10] =. As such, the fine-structure constant is just a quantity determining (or determined by) the elementary charge : e = √ 4 πα ≈ 0.302 822 12 in terms of such a natural unit of charge.