Biology - Food chains and cycles

HideShow resource information

Food chains show the feeding relationships between living things. Pyramids of biomass reveal the mass of living material at each stage in a chain. The amount of material and energy decreases from one stage to the next. Food production is more efficient if the food chain is short, or if energy losses from animals are reduced.

The carbon cycle shows how carbon moves from the atmosphere, through various animals and plants, then back to the atmosphere again.

Food chains

food chain shows what eats what in a particular habitat. For example, grass seed is eaten by a vole, which is eaten by a barn owl. The arrows between each item in the chain always point in the direction of energy flow - in other words, from the food to the feeder.

The Sun is the ultimate source of energy for most communities of living things. Green plants absorb some of the Sun’s light energy to make their own food byphotosynthesis. The other organisms in a food chain are consumers, because they all get their energy and biomass by consuming - eating - other organisms.

It helps if you can recall the meaning of some common words used with food chains.

Common words used with food chains and their meaning

WordMeaning Producers Green plants - they make food by photosynthesis. Primary consumers Usually eat plant material - they are herbivores. For example rabbits, caterpillars, cows and sheep. Secondary consumers Usually eat animal material - they are carnivores. For example cats, dogs and lions. Predators Kill for food. They are either secondary or tertiary consumers Prey The animals that predators feed on. Scavengers Feed on dead animals. For example, crows, vultures and hyenas are scavengers. Decomposers

Feed on dead and decaying organisms, and on the undigested parts of plant and animal matter in faeces.                                                        

Energy transfer

Energy is transferred along food chains from one stage to the next. But not all of the energy available to organisms at one




A well presented set of notes on food chains, energy flows and the carbon cycle. There are some colourful diagrams included but it would be very useful to add a simplified version of the carbon cycle to make these complete. This topic is found in most GCSE Biology specifications.

Similar Biology resources:

See all Biology resources »See all Energy flow through ecosystems resources »