ProducersThe first trophic level. Producers make their own food using sunlight.
Primary consumersThe second trophic level. They eat producers, as a rabbit eats plants.
Secondary consumersThe third trophic level. They eat primary consumers, as a fox eats rabbits.
Tertiary consumersThe fourth trophic level. They eat secondary consumers.
Energy up, heat out 4
Energy passed upAbout 10 percent of the energy moves up a level.
Energy lost as heatMost of the energy at each level leaves as heat.
AutotrophsLiving things that make their own food. Producers are autotrophs.
HeterotrophsLiving things that eat other living things. Every consumer is a heterotroph.
Three kinds of pyramid 3
Pyramid of energyCompares the energy at each trophic level.
Pyramid of biomassCompares the mass of living things at each level.
Pyramid of numbersCompares how many living things are at each level.
How this list was compiled: Every name checked on 2026-10-01 in two independent sources. National Geographic Education encyclopedia entries (one source): Energy Transfer in Ecosystems, https://education.nationalgeographic.org/resource/energy-transfer-ecosystems/ (food chains drawn as energy pyramids, a step for each trophic level with primary producers at the bottom; on average only about 10 percent of the energy passes up from each level; energy is changed to heat); Food Chain, https://education.nationalgeographic.org/resource/food-chain/ (producers or autotrophs as the first trophic level, primary, secondary and tertiary consumers); Heterotrophs, https://education.nationalgeographic.org/resource/heterotrophs/; Food Web, https://education.nationalgeographic.org/resource/food-web/ (energy lost as heat or waste). Wikipedia: Ecological pyramid, https://en.wikipedia.org/wiki/Ecological_pyramid (pyramid of energy, of biomass and of numbers; about 10 percent); Trophic level, https://en.wikipedia.org/wiki/Trophic_level (levels one to four; rabbits eat plants, foxes eat rabbits, golden eagles eat foxes; producers are autotrophs and consumers heterotrophs); Energy flow (ecology), https://en.wikipedia.org/wiki/Energy_flow_(ecology) (at each step energy is lost as heat). The three kinds of pyramid were also read in passages found by full-text search of the Internet Archive: Food Chains (1998), https://archive.org/details/foodchains0000silv, and Ecology: Science of Survival (1971), https://archive.org/details/ecologyscienceof0000unse. Licence: own work
The drawing: Drawn for this site on 2026-10-01 from plain geometry. Own original drawing; nothing is traced or copied. Licence: own work
How it works
Label the energy pyramid one tier at a time, from the producers at the base to the tertiary consumers at the tip. A second view sets three kinds of pyramid side by side.
Read the full guide
Why it is a pyramid
Each tier is a trophic level. Producers make food from sunlight; primary consumers eat them, secondary consumers eat those, and tertiary consumers sit at the tip. Only about 10 percent of the energy in one level is passed to the next. Most of the rest leaves as heat, so each tier is narrower than the one below.
Three kinds of pyramid
A pyramid of energy compares the energy at each level, a pyramid of biomass the mass of living things, and a pyramid of numbers how many there are. The last two can be upside down; a pyramid of energy cannot.
Questions and answers
What are the levels of an energy pyramid?
From the base up: producers, primary consumers, secondary consumers and tertiary consumers. They are trophic levels one, two, three and four.
What is the 10 percent rule?
On average only about 10 percent of the energy stored in one trophic level is passed to the next. National Geographic says this limits how many trophic levels an ecosystem can support.
Where does the rest of the energy go?
Most of it is changed to heat as living things respire. Some leaves as waste, and some animals and plants die uneaten.
What is the difference between autotrophs and heterotrophs?
Autotrophs make their own food and are the producers at the base. Heterotrophs get energy by eating other living things, so every consumer above the base is one.