Chapter 3 The law of conservation of energy states that energy may neither be created nor destroyed. Therefore the sum of all the energies in the system is a constant.

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Photosynthesis Another example off the “interweb”… what do you see that’s different from the last slide?

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Gross and net primary productivity The amount of energy available in an ecosystem determines how much life the ecosystem can support. Producers typically capture only about 1 percent of available solar energy via photosynthesis. The energy they capture (gross primary productivity, or GPP) can be divided into energy used for the producers’ respiration and energy available for the producers’ growth and reproduction (net primary productivity, or NPP). (Friedland page 63)

1 st Law of Thermodynamics: Just as matter can neither be created nor destroyed, energy is neither created nor destroyed. – You can’t get something from nothing. When an organism needs biologically usable energy, it must convert it from an energy source such as the Sun or food.

2 nd Law of Thermodynamics: when energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes. Energy efficiency is the ratio of the amount of work that is done to the total amount of energy that is introduced into the system in the first place.

Energy (Trophic) Pyramid Each Trophic level retains only 10% of the energy from it’s food source…

Trophic pyramid Figure 3.9 Trophic pyramid for the Serengeti ecosystem. This trophic pyramid represents the amount of energy that is present at each trophic level, measured in joules (J). While this pyramid assumes 10 percent ecological efficiency, actual ecological efficiencies range from 5 to 20 percent across different ecosystems. For most ecosystems, graphing the numbers of individuals or biomass within each trophic level would produce a similar pyramid. (page 39)

Recycling Organisms In the end, each trophic level eventually produces dead individuals and waste products that feed other organisms Scavengers are carnivores, such as vultures, that consume dead animals. Detritivores are organisms, such as dung beetles, that specialize in breaking down dead tissues and waste products (referred to as detritus) into smaller particles. These particles can then be further processed by decomposers: the fungi and bacteria that complete the breakdown process by recycling the nutrients from dead tissues and wastes back into the ecosystem. Without scavengers, detritivores, and decomposers, there would be no way of recycling organic matter and energy, and the world would rapidly fill up with dead plants and animals.

Calories The energy needed to raise the temperature of 1 gram of water through 1 °C

Food Chain / Web