4b) Feeding relationships

Chains

• Start with a producer which make their own food from sun's energy 
• Primary consumers eat producers (herbivores) 
• Secondary consumers (carnivores) 
• Then tertiary consumers (carnivores) eat secondary consumers 
• Decomposers break down dead materials and waste 
• Stages are called TROPHIC LEVELS 
• Example: Grass ------> Rabbit ------> Fox 

Food chains are a sequence of feeding relationships between organisms showing who eats what and the movement of energy through trophic levels. 

Food webs is a network of interconnected food chains. It shows that one species affects another  

Pyramids of numbers: show the feeding relationships in the community- it takes many plants to feed herbivores and many herbivores to feed one carnivore. 

Pyramids of biomass: Shows mass of living material at each stage of the food chain is always less than the previous.

Pyramids of energy transfer: shows the transfer of energy through the food chain. 

Energy transfer:

1. Energy from sun
2. Plants photosynthesise
3. 90% of energy lost 
4. Some parts aren't eaten e.g. roots or bones and due to waste (faeces) 
5. Life processes e.g. respiration use some energy 
6. Move energy eventually lost to heat 
7. 10% total biomass 
• This is the energy that is transferred