Food Web
A food web is a complex network of interconnected food chains within an ecosystem, showing all the feeding relationships among organisms and the multiple pathways through which energy and nutrients flow. Unlike a simple linear food chain, a food web more accurately represents real ecosystems where most organisms eat more than one type of food and are eaten by more than one predator. Food webs are used to model the cascading effects that result from changes in species populations, such as the removal of a keystone species.
Food Chain vs Food Web — Key Differences
| Feature | Food Chain | Food Web |
|---|---|---|
| Structure | Linear, single pathway | Network of multiple pathways |
| Complexity | Simple | Complex and realistic |
| Stability | Fragile (single link loss = collapse) | Stable (redundant pathways) |
| Energy flow | Single route | Multiple routes simultaneously |
| Example | Grass → Cow → Human | Savanna with 20+ species interactions |
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Related Terms
Food Chain
A food chain is a linear sequence showing how energy and matter are transferred from one organism to the next through feeding relationships, beginning with a producer and ending with a top predator or decomposer. Each link in the chain represents a trophic level, and only about 10% of the energy from one level passes to the next due to metabolic losses. Food chains illustrate the flow of energy through an ecosystem and help predict the effects of removing or adding species.
Trophic Level
A trophic level is a position in a food chain or food web occupied by organisms that obtain their energy from the same source and in the same number of steps from the primary producers. Level 1 consists of producers (plants), level 2 of primary consumers (herbivores), level 3 of secondary consumers, and so on. Due to the 10% energy transfer rule, food chains rarely extend beyond four or five trophic levels.
Ecosystem
An ecosystem is a biological community of interacting organisms together with the physical environment they inhabit, including all living (biotic) and non-living (abiotic) components. It represents a functional unit of ecology where energy flows and nutrients cycle between organisms and their environment. Ecosystems range in scale from a small pond to the entire Amazon rainforest and are the foundational units studied in ecology.
The concept of a food web (as opposed to a simpler chain) was developed and formalised by Charles Elton (1927) and later elaborated by ecologists including Robert MacArthur. Web derives from Old English webb (woven fabric), referring to the interlaced network of connections.