Explanation

Trophic levels show how energy moves through an ecosystem from one group of organisms to another. The first level includes producers like plants that make food using sunlight. Each level above represents organisms that eat the level below them.

Energy flows upward through the trophic levels but decreases at each step. Producers capture solar energy, herbivores eat producers, carnivores eat herbivores, and decomposers break down dead organisms. Only about 10% of energy passes from one level to the next.

Biological diversity describes the variety of species, not energy flow. Nutrient cycling moves chemicals through the ecosystem but is separate from trophic levels. Ecological interactions include all relationships between organisms, which is broader than just feeding relationships.