1.9 & 1.10 Trophic Levels & The 10% Rule

Trophic Levels

The hierarchical levels in an ecosystem, consisting of producers, primary consumers, secondary consumers, and tertiary consumers, that represent the flow of energy and matter.

10% Rule

The approximate amount of energy that is transferred from one trophic level to the next, with only about 10% of the energy being passed on.

Biogeochemical Cycles

The cycles that demonstrate the conservation of matter in ecosystems, where elements such as carbon, nitrogen, water, and phosphorus are continuously recycled between the environment and organisms.

Conservation of Matter & Energy

The principle that matter and energy are never created or destroyed, but only change forms, as demonstrated by biogeochemical cycles and the first law of thermodynamics.

2nd Law of Thermodynamics

The law that states that each time energy is transferred, some of it is lost as heat, resulting in a decrease in usable energy, as applied to food webs and energy transfer in ecosystems.

Trophic Pyramid

A model that represents the flow of energy through an ecosystem, with each level of the pyramid representing a trophic level and showing the decrease in available energy as you move up the food chain.

Tertiary Consumers

Animals that eat secondary consumers or carnivores and omnivores, often referred to as top or apex predators.

Secondary Consumers

Animals that eat primary consumers or herbivores, including carnivores and omnivores.

Primary Consumers

Animals that eat plants, also known as herbivores.

Biomass

The total mass of all living things at each trophic level in an ecosystem, with only about 10% of the biomass being able to be grown or supported due to the 10% rule.