🔗 Food Chain

A food chain is a simple, straight-line diagram showing the flow of energy and nutrients through an ecosystem, from one organism to another.

Example: Grass → Grasshopper → Frog → Snake → Eagle

Each organism in the chain is linked to the next as a source of food.

🕸 Food Web

A food web is a complex, realistic model made up of interconnected food chains. It shows that:

• Most organisms eat more than one type of food
• Energy flows in multiple directions
• Food webs are more likely to exist in nature than simple chains

🧩 Roles in a Food Chain / Web

1. 🌱 Producers (Autotrophs)

• Make their own food
• Photosynthetic or chemosynthetic organisms
• Chemosynthetic organisms (e.g., deep-sea bacteria) create food using chemical energy from volcanic vents
• Photosynthesis uses sunlight to create food
• Base of all ecosystems

2. 🐛 Primary Consumers (Herbivores)

• Eat producers (plants or algae)

3. 🦎 Secondary Consumers (Carnivores or Omnivores)

• Eat primary consumers

4. 🐍 Tertiary Consumers

• Eat secondary consumers
• Often top predators

5. 🍄 Decomposers

• Break down dead organisms and waste
• Return nutrients to the soil
• Examples: Fungi, bacteria

6. 🐜 Detritivores

• Eat dead organic matter (detritus) but don’t fully decompose it
• Examples: Earthworms, millipedes

7. 🦅 Scavengers

• Eat dead animals (carcasses) but don’t hunt them
• Examples: Vultures, hyenas

♻ Energy Transfer in Food Chains

When energy moves from one organism to the next:

• Only about 10% is passed on
• 90% is lost as:
  • 🔥 33.33% used in respiration (movement, heat, daily functions)
  • 💩 50% is not absorbed (lost as waste, undigested food)
  • ⚡ Only 17.66% is stored as biomass (used for growth and passed on)

That's why food chains usually have no more than 4–5 links — not enough energy remains for many levels.

✅ Key Points to Remember

• Food webs are more realistic than simple food chains
• Roles: Producers → Consumers → Decomposers, with specialized roles (detritivores, scavengers, etc.)
• Some producers use chemosynthesis (no sunlight)
• Energy is lost at every level; only 10% is passed on
• Organisms can play multiple roles in a food web (e.g., a bear is both herbivore and carnivore)

Written by Kasiban Parthipan