Food Chains and Food Webs Science Food Chains and Food Webs

Most animals have a varied diet. A food chain is part of a much larger picture called the food web. Food chains and food webs tell us about the feeding relationships of organisms in an ecosystem. We know which organisms are part of a particular food chain or food web, however we cannot show the numbers involved in them.

Organisms can be divided into to 2 groups:- Producers and Consumers. All plants are producers, this is because they use the sun’s energy to produce food energy. All animals are consumers because they eat either Plants (Producers), Animals ( Carnivore) or Both ( Omnivore).

Consumers can be divided further into: Primary Consumer, Secondary Consumer and Tertiary Consumer. Primary Consumers feed on Producers, for example a rabbits feed on grass . Secondary Consumers are animals that eat primary consumers. Tertiary consumers eat secondary consumers.

Food Chains. Food chains show an example of one relationship between organisms The arrows so the way energy is passed along the food chain or in other words, the arrow say “is eaten by”.

Food Webs. Food webs are similar to food chains but are generally more complex. A food web unlike a food chain will show a more accurate feeding relationship between organisms. Most organisms have more than one food source.

Food Webs, Continued... Food webs can sometimes get broken or have “holes” put in them. This would involve an animal being wiped out. If an animal was to be wiped out to be wiped out it would have side effects. For example, if a frog who ate slugs and was eaten by a perch was wipe out the slugs population would increase (due to not being eaten) and the perch population would decrease due to not getting food. However nature is very good at balancing food webs out. Although the slugs population would increase initially it would eventually decrease or stop increasing due to being eaten by a another animal, e.g. lizard. As for the perch the perch as can be shown in a food web would find a alternative food source.

Summary Within an ecosystem plants and animals rely on others to provide them with the nutrition that they need. The way that animals and plants are linked together can be shown in a simplified sequence called a food chain. The example above shows the food chain from the sun and water through to the primary, secondary and tertiary consumers (Hawk) Producer— Normally a green plant that gets its energy from the sun through photosynthesis Primary consumers are animals that feed on the producers. An example is a rabbit eating grass Secondary consumers are animals that eat the primary consumers. An example is a fox eating a rabbit. Tertiary consumers are animals that feed on the secondary consumers. An example is a bear eating a fox. A food web is a more complex form of the food chain that takes into consideration the fact that animals may belong to many different chains, and so they can all combine to form a web.

Activity Time Click below