Chapter 3.1

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.

What is made of….?

PhosphorousPotassiumNitrogenSulfurMagnesiumIron

Page 60

Photosynthesis

Page 60

• Figure 3.7 Gross and net primary productivity. 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).

Energy Pyramid

Trophic pyramidFigure 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)

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

Food Chain / Web