The Marine Society & Sea Cadets

The diagram below shows how an ecosystem works. All living things need energy to survive and energy flows through an ecosystem along a food chain.

The Sun
This is the source of energy in an ecosystem and without plants to convert solar energy, most life on Earth would cease to exist. Light energy from the sun is absorbed by green plants through Photosynthesis

Plants
The bottom or start of a food chain is made up of producers, such as algae or plants. As well as getting energy from the sun, plants absorb minerals (from rock breakdown) from the soil, through their roots. Energy is stored in stems, leaves and seeds.

Herbivores
Some animals only eat plants, these are called Herbivores. By eating plants, the energy and nutrients are transferred to the animals and are stored in their bodies as muscle and fat.

Carnivores
Carnivores eat other animals. The energy and nutrients are transferred again. Some animals eat plants and animals, these are called Omnivores.

Decomposition
When organisms die, the nutrients are returned to the soil. Fungi and bacteria decompose the dead material, making it ready for re-use. This means the process goes in a circle. In real life, food chains are interrelated (connected) because animals do not eat the same food every meal and so food chains become inter-connected to form food webs.

Scientists study ecosystems for a variety of reasons:

• They can look at the relationship between the biotic and abiotic environment in a variety of places (land, sea.)
  
• They can use this information to learn more about natural changes and help to predict them.
  
• They can look at how the actions of humans can harm or protect ecosystems.
  

The World has many different ecosystems. Each one has its own climate, soil, plants and animals as over thousands of years, trees, animals and plants have adapted to different conditions round the world. Very few ecosystems are natural today because of human activities.