Feeding relationships

producers

producers

an organism that makes its own food

eg. green plants (photosynthesis)

consumers

a living organism that eats other plants and animals.

eg. a human

decomposers

• organisms that feed on dead/decaying plants/animals by secreting enzymes.

• they produce small, soluble food molecules. the food molecules diffuse into the decomposer

  eg. fungi

primary consumers

feeds on producers

eg. herbivores

secondary consumers

feeds on primary consumers

eg. predators

tertiary consumers

feeds on secondary consumers

eg. predators

trophic level

the different feeding levels in a food chain

food chain

• A food chain shows the transfer of energy from one organism to the next

• The source of all energy in a food chain is light energy from the sun

• The arrows in a food chain show the transfer of energy from one trophic level to the next

food web

a network of interconnected food chains.

pyramids of number

• shows how many organisms are in each level of a food chain.

• The width of the box indicates the number of organisms at that trophic level.

pyramids of biomass

• shows how much mass the creatures at each level would have without all the water that is in the organisms (their ‘dry mass’)

• the mass of organisms always decreases as you move up the triangle.

pyramids of energy transfer

• shows the amount of energy contained within the biomass of individuals (within different trophic levels.)

• The area of each box = amount of energy present.

• Pyramid always has a wide base (due to the large amount of energy contained within the biomass of producers)

• As you move up the pyramid to higher trophic levels the quantity of energy decreases because not all energy is transferred to the biomass of the next trophic level.

how does energy transfer along a food chain?

1. all energy comes from the sun: producers generate glucose via photosynthesis.

2. primary consumers (herbivores) feed on plants and gain energy)

3. process continues up the food chain

4. decomposers break down dead organic matter, and recycle the nutrients.

why does only 10% of energy transfer from one trophic level to the next?

• material not eaten by consumer

• material not consumed, but is passed out as faeces.

• energy used by consumer for movement.

• energy used for metabolic processes in consumers body (which releases heat.)

• energy used in generating heat

• energy lost in urine.