Feeding Relationships

Feeding Relationships

Food Chains and Food Webs

  • A food chain shows the transfer of energy from one organism to another, beginning with a producer.
  • Each stage in a food chain is called a trophic level.
  • A food web is a complex network of interconnected food chains, showing how energy transfers through an ecosystem.

Producers, Consumers, and Decomposers

  • Producers are organisms that can produce their own food through photosynthesis, such as green plants.
  • Consumers are organisms that obtain energy by eating other organisms.
  • Consumers can be categorised as: primary consumers (herbivores that eat producers), secondary consumers (carnivores that eat primary consumers), and tertiary consumers (carnivores that eat other carnivores).
  • Decomposers are organisms that break down dead or decaying organisms, returning nutrients to the soil for reuse by producers.

Energy Transfer in Ecosystems

  • Energy is transferred from producers through various trophic levels via consumers when they eat.
  • Energy transfer is not 100% efficient — at each level, much of the energy is lost through bodily functions or as heat.
  • As energy is lost at each trophic level, there are usually only a few levels in a food chain. This is known as the energy pyramid.

Predator and Prey Relationships

  • A predator is an organism that captures and eats other organisms (the prey).
  • A prey is an organism that is eaten by a predator.
  • The number of predators and their prey in an ecosystem are closely linked and often show cyclical changes.

Biomass and Energy at Each Trophic Level

  • Biomass refers to all the living material in an organism. It is a measure of the number or mass of organisms at each trophic level.
  • The pyramid of biomass shows the mass of organisms at each trophic level in a food chain.
  • Energy and biomass decrease at each higher trophic level - this is depicted in a pyramid of energy.

Adaptations for Feeding

  • Predator and prey organisms exhibit different adaptations to enhance their survival.
  • Predators may have adaptations for efficient hunting, such as sharp teeth and claws, keen senses, and the ability to run quickly.
  • Prey animals may have adaptations to avoid predators, including camouflage, warning colouration, and defensive structures like shells and spines.