CIE iGCSE Co-ordinated Sciences-B18.1 Energy flow - Study Notes- New Syllabus
CIE iGCSE Co-ordinated Sciences-B18.1 Energy flow – Study Notes
CIE iGCSE Co-ordinated Sciences-B18.1 Energy flow – Study Notes -CIE iGCSE Co-ordinated Sciences – per latest Syllabus.
Key Concepts:
Core
- State that the Sun is the principal source of energy input to biological systems
- Describe the flow of energy through living organisms, including light energy from the Sun and chemical energy in organisms, and its eventual transfer to the environment
CIE iGCSE Co-Ordinated Sciences-Concise Summary Notes- All Topics
The Sun – Source of Energy
📌 Key Statement
The Sun is the principal source of energy input to biological systems.
🌱 Why the Sun is Important
- Plants absorb light energy from the Sun for photosynthesis.
- Photosynthesis converts light energy → chemical energy (glucose).
- This chemical energy is passed along food chains when animals eat plants.
- Therefore, all life depends on the Sun’s energy (except some deep-sea bacteria that use chemical energy).
📊 Summary Table
| Role of Sun | Explanation |
|---|---|
| Energy for photosynthesis | Light captured by chlorophyll → glucose made |
| Base of food chains | Plants (producers) store Sun’s energy in food |
| Transfer through ecosystem | Herbivores eat plants → carnivores eat herbivores |
| Global importance | Drives climate and supports nearly all life |
⚡ Quick Recap
Sun = main energy source for almost all ecosystems.
Plants trap sunlight → chemical energy → passed along food chains.
Without the Sun → no photosynthesis → no life.
👉 Memory trick: “Sun → Plants → Food → Life.”
Flow of Energy in Living Organisms
📌 Introduction
Energy flows through ecosystems in one direction:
☀️ Sun → 🌱 Producers → 🐇 Consumers → 🦅 Top consumers → 🌍 Lost as heat
🌱 Step 1: Light Energy from the Sun
- The Sun is the main energy source for almost all life.
- Plants (producers) absorb light energy using chlorophyll.
- Photosynthesis converts it into chemical energy stored in glucose.
🐾 Step 2: Chemical Energy in Organisms
- Plants use glucose for growth and energy.
- Energy is passed along food chains:
- Herbivores eat plants (gain stored energy).
- Carnivores eat herbivores (energy transfer continues).
- At each step, only a small fraction of energy is passed on (most is lost).
🌬️ Step 3: Energy Transfer to the Environment
- Energy is eventually lost to the environment as:
- Heat from respiration
- Movement of organisms
- Waste products (e.g., undigested food, excretion)
- This energy cannot be recycled, but nutrients can.
📊 Summary Table
| Stage | Energy Form | Notes |
|---|---|---|
| Sun | Light energy | Main input to life on Earth |
| Plants | Chemical energy in glucose | Photosynthesis stores energy |
| Animals | Chemical energy in food | Transferred along food chains |
| Environment | Heat & waste | Energy lost, not recycled |
⚡ Quick Recap
Sunlight → chemical energy (plants) → chemical energy (animals) → lost as heat.
Energy flows one-way, nutrients recycle.
👉 Memory tip: “Sun → Plant → Animal → Heat.”