Trophic Levels

Trophic Levels

• Definition: A trophic level is a feeding level in a food chain. (“Trophic” = feeding)

• Levels in a food chain:

  1. Producers – make their own food via photosynthesis (plants & algae).

  2. Primary consumers – herbivores that eat producers.

  3. Secondary consumers – carnivores that eat herbivores.

  4. Tertiary consumers – carnivores that eat other carnivores.

• Apex predators:

  • Carnivores at the top of the food chain.

  • Have no natural predators.

Decomposers

• Role: Break down dead plants, animals, and waste (e.g., feces).

• Function:

  • Secrete enzymes to digest dead material outside their bodies.

  • Absorb the soluble nutrients (mineral ions) back into their cells.

  • Return minerals to the soil → essential for plant growth and ecosystem cycling.

✅ Key Idea:

• Trophic levels show feeding relationships in ecosystems.

• Decomposers recycle nutrients, maintaining the balance in ecosystems.