GCSE Biology: Energy Flow in Food Chains
- All living organisms need energy.
- They get this energy from food, by respiration.
- all the energy in an ecosystem comes from the sun.
- Producer, green plants convert the energy from the sun into glucose by photosynthesis.
- Animals get their energy by eating plants, or by eating animals that have eaten plants.
- s energy moved from one animal to another we call this path the food chain.
- Every food chain begins with green plants as they are the only organisms which can capture the suns light.
- All animals are consumers. An animal which eats plants is a primary consumer, and an animal that eats other animals that have eaten plants is a secondary consumer.
- Food chains are usually short because the energy passed along gets less and less and organisms use the energy to survive.
- Many food chains have only three links, and very few have more than five.
- The number of organisms in each food chain can be shown in a number pyramid. The width of the block indicates the relative numbers.
- Each level in a pyramid is called a feeding or trophic level.
This pyramid is "pyramid shaped" as there are more producers than there are primary consumers, and more secondary consumers than there are primary consumers.
This pyramis is not "pyramid shaped" as there is only a single oak tree, a very small number of oak trees compared to the number of caterpillars. This pyramid still illustrates the number of organisms at each trophic level.