4.1 Following the food web in Wicken Fen
The definition of an ecosystem can be framed in terms of energy flow. You need to know what organisms are living in it – the biodiversity of the system. Next, you can work out how the organisms are linked.
The sum of the nutritional links between organisms in an ecosystem is known as the food web.
There are two food webs mentioned in the film and one animal that links them together. What is the significance of this link?
Note your thoughts in the box provided.
The dragonflies link the aquatic with the terrestrial food webs. Energy obtained by the dragonfly larvae feeding below the surface is transferred to the terrestrial food chain. This example emphasises the complexity of links that need to be unravelled if a picture of energy flow is to be drawn accurately.