Food Chains and Food Webs

Biomass

The total amount of living organic matter in a trophic level. Decreases as you move up the food chain because energy is lost at each step.

Ecological management for ecological stability

Strategies used to maintain healthy ecosystems, such as habitat protection, reducing pollution, sustainable harvesting, and controlling invasive species to preserve balance.

Energy flow

Movement of energy through an ecosystem from the sun → producers → consumers → decomposers. Energy decreases at each step due to heat loss.

Food chain

A linear sequence showing who eats whom. Shows ONE path of energy flow in an ecosystem.

Food web

A complex network of interconnected food chains. Shows ALL feeding relationships in an ecosystem.

Interspecific competition

Competition between different species for limited resources (food, space, water). Can lead to resource partitioning or competitive exclusion.

Predator-prey interactions

Relationship where one organism (predator) hunts another (prey). Helps regulate population sizes and drives natural selection.

Second Law of Thermodynamics (in ecology)

When energy is converted, some is lost as heat. Explains why only ~10% of energy moves to the next trophic level.

Top-down control

When predators at high trophic levels regulate the structure of lower trophic levels. Example: Removing wolves → deer increase → plants decrease.

Bottom-up control

When primary producers or nutrient availability determine ecosystem structure. Example: More nutrients → more plants → more herbivores.

Trophic dynamics

The study of energy and biomass movement through trophic levels in an ecosystem.

Trophic levels

The feeding positions in a food chain (producers → primary consumers → secondary consumers → tertiary consumers → decomposers).

10% rule

Only about 10% of the energy at one trophic level is passed to the next; the rest is lost as heat (due to the second law of thermodynamics).