Ecosystems Curriculum

This section addresses students' tendency to miss cyclic causal relationships. It helps students to realize that the same atoms are continuously recycled between the living and non-living parts of an ecosystem. This "circle of decay" is always happening. A contrast is drawn between matter, which is recycled, and energy, which is not.

Section 2: Understanding Goals

Subject Matter

• When dead matter decomposes it does not disappear, but is recycled through living things and the physical environment. (The atoms are recycled.)
• When dead matter decomposes it breaks down into its basic elements, some of which are nutrients.
• The nutrients from dead matter are put back into the surrounding physical environment (soil, water, air) by decomposers.
• The nutrients in soil make the soil a good environment for new plants to grow.
• Nutrients are passed along the food web from plants to animals, from animals to animals, from dead plants and animals to decomposers, and finally back to plants via soil, air and water.
• The matter cycle (of producers to consumers to decomposers back to producers, and so on) is crucial to the rest of the food web and the ecosystem as a whole.

Causality

• In cyclic causality, there is no real beginning or ending.
• There are cycles of decay happening all of the time (simultaneously). Thus there will always be nutrients being made available in the ecosystem.