Food chains & Predator Prey Cycles

• A model that shows how energy passes from organism to organism is called a food chain.
• Organisms at the very start of a food chain that can create glucose using photosynthesis are known as producers.
• Which two of the following groups of organisms are producers?

  algae

  plants

  
  

  Producers are organism that create their own food using energy from the sun.
• Which resource do plants not compete for?

  Food
• What do primary consumers feed on?

  Producers 
• Tertiary consumers are organisms that eat secondary consumers. 
• As energy passes along a food chain, most of the energy is lost
• Which is the secondary consumer in the following food chain?

  tree → caterpillar → shrew → owl

  shrew
• What is a predator? 

  An animal that hunts and kills other animals for food
• An organism that is killed and eaten by a predator is known as prey.
• The diagram above shows the predator-prey cycle between snakes and rabbits.

  1. At time X, the number of predators is increasing because there is a lot of prey.
  2. At time Y, the number of predators is decreasing because there is less prey.
  3. At time Z, the number of prey is decreasing because there are now more predators.