Idea or model
Food chains and webs
Who eats whom in an ecosystem. Energy and nutrients pass from producers to the animals that eat them.
Energy flow
Energy enters most ecosystems as sunlight and is lost at each step up a food chain, which limits how many levels it can support.Source: OpenStax, 2018
Process
How Energy flow connects
Energy flow involves
Energy flow includes
Process
Primary production
Carbon fixed by plants, algae and photosynthetic microbes: about 105 billion tonnes a year worldwide, roughly half on land and half in the ocean.
Studied in
Your progress
Sources & further reading
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Biology 2e (opens the original in a new tab)
OpenStax (2018). OpenStax, Rice University.
Free introductory college textbook.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)