Summary
An interlinked network of food chains showing feeding relationships in a community.
In depth
Webs show complexity, including omnivores and generalists. Species with many links are less vulnerable to a loss of one food source, but removing keystone species may collapse the web.
Webs can be used to study bioaccumulation and stability.
Webs help predict indirect effects: removing a predator can raise prey and reduce prey's resources. Web complexity differs between ecosystems.
Example: if sea otters decline, urchins rise, and kelp falls.
Webs are described by connectance (the proportion of possible links realised), chain length and the numbers of top, intermediate and basal species. Omnivory, cannibalism and ontogenetic diet shifts add complexity. Stable webs usually have many weak interactions and a few strong ones, which dampen oscillations.
Removing a species can have indirect effects: when sea otters were hunted, urchins grazed kelp forests into barrens, and many fish and invertebrates that depended on kelp declined. Webs help predict outcomes of invasive species and overfishing, and they can be built from gut contents, isotopes or DNA metabarcoding of faeces.
Key idea: a web shows many pathways, so feeding relationships are better described as a network than as a line.
Frequently asked questions
What is Food Web?
An interlinked network of food chains showing feeding relationships in a community.
Which area of biology covers Food Web, and how advanced is it?
Food Web is one of the 54 topics in Ecology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Food Chain, Food Web Stability, Trophic Cascade.
Can you give an example of Food Web?
In the Arctic, the loss of sea ice affects algae, zooplankton, fish, seals and polar bears.
What should I learn before Food Web?
Food Web is a Beginner topic, so no earlier topic is required. Other Beginner topics in Ecology that pair well with it include Ecology, Ecosystem, Biotic and Abiotic Factors.
What topics are related to Food Web?
The closest topics to Food Web are Food Chain, Food Web Stability, Trophic Cascade, Allee Effect. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Food Web?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Food Web. To practise the whole of Ecology, use the Ecology quiz.
How is Food Web different from Food Chain?
Food Web: An interlinked network of food chains showing feeding relationships in a community. Food Chain: A linear sequence showing who eats whom, beginning with a producer. Read both side by side and note what each one explains.
How should I study Food Web step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Food Chain and explain the difference aloud. Finally, take the Ecology quiz and come back to this page for any question you miss.