In this IBDP biology post, we will be looking at how energy flows between different animals, and the food chain. Let's go!
Photoautotrophs and Chemoautotrophs
Photoautotrophs:
Use pigments such as chlorophyll to trap light energy which is converted into chemical energy in carbon compounds
Chemoautotrophs:
Use energy from chemical processes
Example: Volcanic vents
All Autotrophs convert Carbon Dioxide [from atmosphere or dissolved in water] into Organic Compounds
Food Chains
Food Chains: Show the flow of energy through the trophic levels of a feeding relationship
Trophic Level: Feeding position of an organism in a food chain
In IBDP Biology, we know that food Chains mostly only have 3 to 4 trophic levels because of Theories of energy flow and energy losses
Only a small proportion of energy and biomass is passed on from one trophic level to another [10%]
The amount of energy drops along Food Chains - 4th and 5th Trophic Levels too little energy remains to sustain another level
Pyramids of Energy
Pyramids of Energy: A diagram that shows the flow of energy between trophic levels in a community
Measured in units of energy, per unit area per unit time KJ m-2 y-1
90% of energy is lost between Trophic Levels:
- Not ingested
- Not digested
- Excreted
- Lost as heat from Respiration
As the Trophic Level increases the biomass and energy available decreases
Energy losses between Trophic Levels limit the length of Food Chains
As energy is lost between Trophic Levels Biomass is lost too [each level smaller than one below]
Biomass is used to indirectly measure energy transfers
Summary:
- Only around 10% of energy is passed on to another chain
- Autotrophs give heterotrophs the needed energy from sunlight
- Biomass and energy decreases ad trophoc levels go higher
That's all! Well done!
Drafted by Venetia (Biology)