In a food chain:
• It starts with the producer and ends with either a secondary consumer or a tertiary consumer.
• Organisms feed on organisms from the previous trophic level.
• Energy is transferred from the consumed organisms to the feeding organisms.
• Energy is transferred between trophic levels when an organism eats other organisms from which it gains its energy. This energy is transferred to the organism after it has digested and assimilated the food to form new substances in the body.
In a food web:
• It shows the feeding relationships in a community.
• It consists of several food chains (Figure 9.7).
• Organisms in all food chains rely on each other in feeding aspects.
• It starts with photosynthetic producers which convert light energy from the sun into chemical energy in the form of food stored in organs such as roots, fruits, stems or leaves.
Hope this helps