A missing link in any food chain can cause major effects on the living things in that food chain
EXAMPLE QUESTIONS
What animals eat plant eating animals?
What different food chains can you think of?
What do you think might happen if a food chain gets broken?
Can you think of any food chain that does not involve green plants?
FOOD CHAINS BEGIN WITH PLANTS
Green plants are the only living things that are able to turn non-living substances (minerals, water and carbon-dioxide) into food and energy.
Animals are dependant upon green plants for their food supplies.
Humans, and some other animals, eat green plants (cabbage, lettuce for example).
We also eat things like potatoes, rice and applies which are food and energy stores built up by green plants.
When we eat the meat of a plant-eating animal, or herbivore, such as cow, sheep or rabbit, we are eating the flesh of an animal that has been created from the stored energy in the plants that it has eaten.
Each change, or transfer of energy via food, is a link in a chain of energy-transfer events, called a food chain.
THERE ARE MANY DIFFERENT FOOD CHAINS
All kinds of food chains exist.
They all begin with plants.
Some small fish feed on sea plants and plankton and then get eaten by bigger fish.
Some of these bigger fish may be eaten by mammals (seals, sea lions or humans, for example) and others may be eaten by birds (such as herons, gulls and ospreys).
Aphids feed on green leaves and some are then eaten by ladybirds; ladybirds are eaten by birds; birds may be eaten by cats.
A SMALL CHANGE IN ONE FOOD CHAIN LINK CAN HAVE FAR-REACHING RESULTS
Because food chains are linked together in many complex ways, even a small break in the chain can have dramatic effects on other parts of the chain.
It can also affect other chains that are connected to that chain.
Changes in animal habitats from natural events such as forest fires, or from human events like the construction of dams or the clearing of land for farming, can severely affect this careful balance.
Killing off a particular plant (because it is seen as a weed) or a creature (because it is considered a pest) can have this effect.
Sometimes a fatal disease epidemic can affect a particular animal within a chain and disrupt the food chain it belongs to.
