food chains

• Food chain


  A list of organisms in a habitat that shows their feeding relationship, i.e what eats what
• Trophic levels


  The stages in food chains
• Producer


  • Usually a green plant or algae that completes photosynthesis to store energy from sunlight as glucose
• Primary consumer


  • Eats a producer
• Secondary consumer


  • Eats a primary consumer
• Tertiary consumer


  • Eats a secondary consumer
• Quaternary consumer


  • Eats a tertiary consumer
• Prey


  • Animals that are hunted and eaten
• Predator


  • Consumes prey
• Top (or apex) predator

  • The final consumer at the top of the food chain that is not eaten by anything else
• There are volcanic vents at the bottom of the oceans where it is so dark that no plant or algae could live. Places like this are the only food chains on Earth that don't start with photosynthesis.
• Chemosynthesis


  The process where bacteria feed directly on the chemicals released from the vents and use a variety of chemical reactions to make glucose
• The Sun's energy


  Converted by plants through photosynthesis, then moves up the food chain to the top predator
• Pesticides like DDT can enter the food chain and have knock-on effects on all the animals up the chain
• If one plant or animal in a food chain is removed, the population of the consumer can grow out of control
• Food web


  All the food chains that make up an ecosystem from producers to consumers to top predators
• Decomposers


  Consume dead animals, decaying plant material and waste products, and return the nutrients to the soil
• Toxic materials can accumulate in the food chain and damage the organisms, particularly the predators at the end of the chain
• Mercury compounds were used to make insecticides and paints, but when mercury gets into a food chain, it damages the nervous and reproductive systems of mammals, including humans