K-3

• All resources used by humans, including fuels, metals, and building materials, ultimately come from the earth and many of these resources are not in endless supply. They must be used with care, conserved, and recycled. (Energy, Systems and Interactions)

3-6

• Humans use air, fresh water, soil, minerals, fossil fuels and other sources of energy that come from the earth; many of these materials are nonrenewable. They must be used wisely and conserved judiciously. (Energy, Systems and Interactions) Nutrients are recycled as living things die and decompose.

6-9

• Matter needed to sustain life is cycled and recycled within ecosystems. Decomposers use organic material from producers, herbivores, and carnivores, and they themselves decompose. Matter is thus partly recycled in the environment. (Patterns of Change, Systems and Interactions)

• Conservation and management of resources are ethical and practical concerns involving pubic policy and individual responsibility. (Energy, Systems and Interactions)

• Public landfills must be planned responsibly to allow maximum use of land once it is reclaimed. Toxic waste buried in landfills adversely affect the groundwater supply and thus affect public water and public health. (Systems and Interactions, Patterns of Change)

9-12

• Matter needed to sustain life in an ecosystem is cycled and reused. Some of the cycles are the carbon cycle, the nitrogen cycle, the water cycle, and various mineral cycles. (Patterns of Change, Systems and Interactions)

• Non-renewable resources can be conserved through careful use, recycling, and application of energy. If the energy applied in recycling and conserving comes from another non-renewable source, then the effect is to trade one non-renewable resource for another. (Energy, Systems and Interactions)

• Environmental reclamation involves the need to restore mining sites, clean up oil spills, and dispose of toxic wastes properly. These responsibilities always accompany the exploitation of natural resources. (Energy, Systems and Interactions)