Student Activity - Making a food web
This activity is a practical way for students to understand the complexity of food webs.
A food chain is used to describe the way energy moves from a producer - a plant - through to a predator. It is a simple linear view of who is eating what. But how many animals eat only one type of food? If you look at the picture below of the Antarctic system you can see that most animals are eating - and being eaten by - more than one animal. This forms a food web, a more complicated but accurate view that helps us to understand how the different living things in an ecosystem depend upon each other.
This diagram shows how the 'food web' in the Ross Sea works. The arrows go from prey species (these get eaten) to predators (the hunters).
- All the students stand in a circle.
- The first student holds onto a ball of string and names a plant.
- Another student names an animal - don’t forget about insects - that eats that plant. They then take the ball of string while the first person holds onto the string end.
- Next someone must come up with something that might eat that animal. This continues until a top level predator is reached.
- Cut the string. You will now have one piece ranging from a plant through a number of animals.
- Name another plant and repeat the procedure. If the same animal is named then the original person must hold the string causing it to cross over.
How complicated does your web become when the same plant or animal is eaten by many animals?
What would happen if you removed any given species or added in something that is not normally part of the natural ecosystem?