Thursday, 27 March 2008

Food Chains/Pyramids

A food chain shows who eats what in a particular habitat. It always starts with a green plnat, as they can produce their own food. Their known as the producers. Animals are the consumers as they eat plants and other animals. The diagram shows, grass is eaten by a vole, which is eaten by a barn owl. The arrows between each item in the chain always point in the direction of energy flow - in other words, from the food to the feeder.

Each animal in a food chain eats another and gains energy, this keeps the ecosystem alive.

Putting this food chain into a pyramid will look like this:

1 Barn owl

25 voles

200 grass seeds

However sometimes food pyramids can look like this:

1 Sparrowhawk

10 Bluetits

200 Caterplillars

1 Tree

If this happens then in order to make it look like a pyramid you can change it into a 'pyramid of biomass' this shows the mass of living material rather than the numbers.

~ Animals that are hunted are care known as the prey.
~ Animals that hunt and eat other animals are called predators.

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