Food Chains and Predator-Prey Cycles

• How do the numbers of predators and prey change over time?

  They change in cycles
• What is a biotic factor that affects organisms?

  A source of food
• What do scientists use to represent feeding relationships?

  Food chains
• What is the first organism in the simple food chain shown?

  Grass
• What is the role of producers in food chains?

  They synthesize complex molecules
• In the food chain with grass, what eats the grass?

  Rabbits
• What do green plants produce through photosynthesis?

  Glucose
• What term do scientists use for molecules like glucose?

  Biomass
• Who are the primary consumers in the food chains discussed?

  Rabbits and caterpillars
• What do we call animals that eat primary consumers?

  Secondary consumers
• In the food chain with a tree, who is the tertiary consumer?

  Bird of prey
• What is the definition of a predator?

  An animal that kills and eats others
• In the food chain with rabbits and foxes, who is the prey?

  Rabbits
• How do predator and prey populations typically behave over time?

  They rise and fall in cycles
• What might cause changes in predator-prey cycles?

  A drought or new predator arrival
• What are the stages in a typical food chain?

  1. Producer
  2. Primary consumer
  3. Secondary consumer
  4. Tertiary consumer
• Describe the relationship between predator and prey populations.

  • Populations rise and fall in cycles
  • Increased prey leads to increased predators
  • Decreased prey leads to decreased predators
• What is a stable community?

  • All biotic and abiotic factors are balanced
  • Populations of organisms remain stable
  • Changes disrupt the balance