Edexcel IGCSE Biology · Spec 4.6-4.9
Feeding Relationships
Food chains and food webs, energy transfer between levels, and pyramids of number and biomass.
Biology revision video
Feeding Relationships
Prefer to watch on YouTube? Open this video on YouTube.
Spec 4.6-4.9
What you need to know
- Name the trophic levels in a food chain
- Read food webs
- Explain energy loss and ecological pyramids
Active recall
Quick check
Answer each question before opening the answer.
What do the arrows in a food chain represent?
The direction of energy/biomass transfer — they point from the food to the organism that eats it.
Why are food chains usually short?
Energy is lost at each level (in respiration, movement and waste), so there is less to support organisms higher up.
Biology video companion
Keep your notes and exam practice together
The free Biology workbook follows every video in specification order.