Energy Flow in an Ecosystem Diagram

All 14 parts on the diagram

Show the list

Energy flow 8

Sun Where the energy comes from. Almost every ecosystem runs on sunlight.
Light energy Energy enters the ecosystem as sunlight.
Producers Plants make their own food using energy from the Sun.
Chemical energy Energy stored in food. It passes on when one living thing eats another.
Primary consumer An animal that eats producers.
Secondary consumer An animal that eats primary consumers.
Decomposers Fungi and bacteria break down whatever dies.
Heat Energy leaves as heat at every step. It does not come back.

Chemical cycling 6

Air The air holds carbon dioxide, which plants take in.
Soil The soil holds nutrients that plants take up.
Uptake by producers Plants take chemicals in from the air and the soil.
Passed on in food Chemicals move on when one living thing eats another.
Dead matter and waste Dead plants, dead animals and waste go to the decomposers.
Returned by decomposers Decomposers put chemicals back into the soil and the air.

How this list was compiled: Every name and statement checked on 2026-10-03 in two independent sources. (1) NOAA Education, Aquatic food webs, https://www.noaa.gov/education/resource-collections/marine-life/aquatic-food-webs : how energy flows through an ecosystem, producers, primary and secondary consumers, decomposers (bacteria and fungi) that recycle what remains into nutrients for producers. (2) NOAA Education, Carbon cycle, https://www.noaa.gov/education/resource-collections/climate/carbon-cycle : plants move carbon from the atmosphere into living things using energy from the Sun, animals that eat plants take it on, and respiration, excretion and decomposition release it back into the atmosphere or soil. (3) CLEAN (Climate Literacy and Energy Awareness Network), Energy Literacy Principle 3, https://cleanet.org/clean/literacy/energy3.html : the Sun is the main energy source for ecosystems and starts the energy flow of almost all food webs; energy moves one way through food webs, from producers on to consumers and decomposers; the chemical elements in living things pass along food chains; a constant supply of energy, mostly sunlight, keeps the process going. (4) Wikipedia: Energy flow (ecology), Photosynthesis, Nutrient cycle, Ecosystem, Decomposer, Trophic level, https://en.wikipedia.org/wiki/Energy_flow_(ecology) : light energy converted into chemical energy by photosynthesis, energy lost as heat at each step, the one-way flow of energy against the cycling of nutrients, chemical energy in food, dead matter broken down by decomposers, nutrients in the soil. (5) J. M. Moran, An Introduction to Environmental Sciences (1973), read by full-text search on archive.org, https://archive.org/details/introductiontoen0000mora_v6n6 : all light energy transformed into chemical energy by photosynthesis is eventually lost as heat energy. (6) Environmental Education Objectives and Field Activities, third edition (Paducah Independent School District, Kentucky, 1970; ERIC ED049026), https://archive.org/details/ERIC_ED049026 : producers convert light energy into chemical energy. Licence: own work

The drawing: Drawn for this site on 2026-10-03 from plain geometry. Own original drawing; nothing is traced or copied. Licence: own work

How it works

This energy flow in an ecosystem diagram shows one meadow twice. First, energy passes through it: in as light, out as heat. Then chemicals cycle around it, between living things, the soil and the air.

Read the full guide

Energy flows one way

Light energy from the Sun reaches the producers, which store some of it as chemical energy in food. That energy passes to the primary consumer, then the secondary consumer, and to the decomposers when anything dies. At each step some leaves as heat.

Chemicals cycle

Producers take carbon from the air and nutrients from the soil. The chemicals are passed on in food. Dead matter and waste go to the decomposers, which return the chemicals to the soil and the air, ready to be used again.

The wavy arrows only point away: heat does not come back to the living things.

Questions and answers

How does energy flow through an ecosystem?

In one direction. Energy enters as sunlight, producers store some of it as chemical energy in food, and it passes to each consumer that eats. At every step some leaves as heat, so new energy has to keep arriving from the Sun.

What is the difference between energy flow and chemical cycling?

Energy passes through once: in as light, out as heat. Chemicals such as carbon are used again and again. They move from the air and the soil into living things, and decomposers put them back.

Where can I drag the labels onto the diagram to identify how energy flows through an ecosystem?

Here, with taps in place of drags. The meadow is this site's own drawing. Press Quiz me on the Energy flow view and tap the Sun, each arrow and each living thing as its name comes up.

Can I drag the labels onto the diagram to identify how chemicals cycle in an ecosystem?

Switch to the Chemical cycling view. It asks the air, the soil and the four arrows between them and the living things. You tap each one, or print the drawing blank and write the names in.

What do decomposers do in an ecosystem?

Decomposers such as fungi and bacteria break down dead plants, dead animals and waste. That returns nutrients to the soil and carbon to the air, where producers can take them up again.