Ecological pyramids are a graphical way to show the effects of the loss of energy. Each level in a pyramid matches a level of a producer or consumer in an ecosystem or food chain. At higher levels, less energy is available. The number of organisms in the level also usually decreases.
KEY IDEAS
1. Only about 10% of the energy is passed onto a predator because the predator uses energy in catching its prety, eating it, and breaking down the large food molecules to simple nutrients.
2. Each individual needs several individuals of prey over a short period of time, so there are usually more producers in an ecosystem than consumers. Consider how many plants a rabbit might eat in one year. It needs more than one plant per year to survive.
3. A food pyramid is narrower in the witner than the the summer due to:
-hibernation
- migration
- weather
- life cycles
- winter kill
- availbility of food