Food chains and Food web

• Producers

  •  make(produce) their own food using energy from the Sun.
  • Producers are usually green plants — they make glucose by photosynthesis.
• When a green produces glucose, some of it is used to make other biological molecules in the plant. These biological molecules are the plants biomass —— the mass of living material.
• Biomass 

  • can be thought of as energy stored in a plant. 
  • is transferred through living organisms in an ecosystem when organisms eat other organisms
  • this means that these photosynthetic organisms support nearly all life on Earth.
• 1. Producers are eaten by primary consumers (usually herbivores).
  2. Primary consumers are then eaten by secondary consumers (carnivores).
  3. Secondary consumers are eaten by tertiary consumers (also carnivores).
• Consumers -  are organisms that eat other organisms.
• Food webs 

  • Shows how food chains are linked.

  There are many different species within an environment — which means lots of different possible food chains. You can draw a food web to show them.

  All the species in a food web are interdependent — they depend on each other for survival.

  The transfer of biomass is one way in which organisms are interdependent.

  The direction of biomass transfer is shown by the arrows in a food chain or web.
• Interdependence - means that a change in the size of one population will affect the sizes of other populations in the community.

  • For example, in the food web on the right, if lots of water spiders died, then:
  • There would be less food for the frogs, so their numbers might decrease.
  •  The number of mayfly larvae might increase since the water spiders wouldn't be eating them.
  • The diving beetles wouldn't be competing with the water spiders for food, so their numbers might increase.