Food chains

 

 

Food chains show the flow of food (chemical potential energy) from one living thing to another. In the picture above, grass is eaten by the sheep which in turn is eaten by humans. All food chains must start with a plant. Plants are known as primary producers because they can trap the sun's energy and produce their own food through a process called photosynthesis. The next living thing to follow the primary producers is a group of living things called first order consumers. Consumers are creatures that eat plants or animals and do not produce their own food.
Caterpillars eat plants and get the food the plant made into their bodies. Caterpillars are known as first order consumers. Birds that do not eat plants will then eat the caterpillar and in turn get the plant food into their bodies. Birds are known as second order consumers. The caterpillar is very important in providing food for many other creatures. Caterpillar's are responsible for supplying the sun's energy, trapped in the plant food, to the birds and in turn any other animal, third order consumer, such as a cat, that eats the bird.
All food chains start with a plant

 

Animals that come just after plants in a food chain are called herbivores. Herbivores are animals that eat only plants. After the herbivores come the carnivores which eat other animals. Only 10% of the energy from one level will flow to the next level. The remaining energy is lost, mainly as heat.

At the end of every food chain there are the minute organisms we call decomposers(bacteria and fungi). These small creatures breakdown the dead matter and return it to the soil for use by other growing animals and plants. Decomposition normally involves the use of oxygen to break down the organic matter However there are bacteria and fungi that can decompose organic matter in the absence of oxygen.

Discuss what the Earth would be like if decomposers were to all suddenly die.

Why do all food chains start with a producer?

What flows from one organism to the next in a food chain?

What type of consumer is the sheep in the food chain above?

If the algae eaten by a fish contain 100 joules of energy what is the number of fish that must be eaten by a pelican so that the pelican gets 100 joules of energy?

 


Ecosystem activity

 

Home of butterflies

Home of stick insects