4.6 Energy and Substances in Food Chains

Bush Grass = Producer
Impala = Primary Consumer
Leopard = Secondary Consumer
Lion = Tertiary Consumer

- Producer: converts light energy into chemical energy. The chemical energy takes the form of organic molecules including: carbohydrates, proteins and lipids. These molecules, which are called food, are composed of:
C-H
C-O
C-C
O-H
C-N
bonds.
- These bonds all represent energy
- Carbon, Hydrogen, Nitrogen and Oxygen are the substances/matter

- As bush grass carries out photosynthesis it creates the organic molecules which are the substances and contain the energy which was fixed from sunlight, now in the form of chemical energy.
- The impala consumes this for: respiration, growth and life processes
- When the leopard eats the impala, these molecules are passed on and re-organized into leopard form, and so on...

Substances/Matter and the energy which is in the bonds between the elements are passed from each stage in the food chain.

4.5(a&b) Food Chains and Food Webs

4.5a Food Chains 



Food Chains link together:
Producer ----> Primary Consumer ------> Secondary Consumer -----> Tertiary Consumer

• Only one organism per trophic level
• You cannot show an organism being an omnivore / cannot show organisms feeding at more than 2 trophic levels
• Food Chains show the flow of matter and flow of energy

4.5b Food Webs




The food web allows us to provide a better description of the ecosystem (ecosystems are community of organisms interacting) In this case interacting = feeding

Feeding at different trophic levels:
consequences
- organisms can have multiple predators
- may be feeding on multiple pray
- resulting to the food chains becoming linked.