Food Webs (Edexcel GCSE Biology: Combined Science)

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Food Webs

  • A food web is a network of interconnected food chains
  • Food webs are more realistic ways of showing connections between organisms within an ecosystem (compared to individual food chains) as animals rarely exist on just one type of food source

Food Web Definitions Table

Types of Variation table, IGCSE & GCSE Biology revision notes

Food web, IGCSE & GCSE Biology revision notes

A food web shows the interdependence of organisms

  • Food webs give us a lot of information about the transfer of energy in an ecosystem
  • They also show interdependence - how the change in one population can affect others within the food web
  • For example, in the food web above, if the population of earthworms decreased:
    • The population of grass plants would increase as there are now fewer species feeding off them
    • The populations of frogs and mice would decrease significantly as earthworms are their only food source
    • The population of sparrows would decrease slightly as they eat earthworms but also have another food source to rely on (caterpillars)

Examiner Tip

Don’t forget – animals (known as consumers) can be at different trophic levels within the same food web as they could be omnivores (animals that can eat both plants and animals) or could be predators that eat both primary, secondary and/or tertiary consumers!Food web showing trophic levels_2, downloadable AS & A Level Biology revision notes

Trophic levels for a simple food web – note that some organisms can belong to more than one trophic level (such as the squirrel, fox and eagle in this food web)

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Lára

Author: Lára

Expertise: Biology Lead

Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.