13.4, food chains and food webs

• Food chains and food webs


  Models the flow of energy in an ecosystem
• Food chain


  A model that shows a sequence of feeding relationships
• Food chain


  • Links species by their feeding relationships
  • Follows the connection between one producer and a single chain of consumers within an ecosystem
• Types of consumers


  • Herbivores
  • Carnivores
  • Omnivores
  • Detritivores
  • Decomposers
• Specialists


  Consumers that primarily eat one specific organism or a very small number of organisms
• Generalists


  Consumers that have a varying diet
• Trophic levels


  • Primary consumers (herbivores that eat producers)
  • Secondary consumers (carnivores that eat herbivores)
  • Tertiary consumers (carnivores that eat secondary consumers)
  • Omnivores (may be listed at different trophic levels in different food chains)
• Food web


  A complex network of feeding relationships that emphasizes complicated feeding relationships and energy flow in an ecosystem
• An organism may have multiple feeding relationships in an ecosystem