Energy flows in one direction through an ecosystem, from the sun or inorganic compounds to producers (organisms that can make their own food) through various levels to consumers (organisms that rely on other organisms for food). Your body gets the energy and materials it needs for growth and repair from the foods you eat.

32 Energy Flow

A. Producers

1. Energy From the Sun

2. Life Without Light

B. Consumers

C. Feeding Relationships

1. Food Chains

2. Food Webs

3. Trophic Levels

D. Ecological Pyramids

1. Energy Pyramid

2. Biomass Pyramid

3. Pyramid of Numbers


33 Cycles of Matter

A. Recycling in the Biosphere

B. The Water Cycle

C. Nutrient Cycles

1. The Carbon Cycle

2. The Nitrogen Cycle

3. The Phosphorus Cycle

D. Nutrient Limitation