CIE iGCSE Biology-19.1 Energy flow- Study Notes- New Syllabus
CIE iGCSE Biology-19.1 Energy flow- Study Notes – New syllabus
CIE iGCSE Biology-19.1 Energy flow- Study Notes -CIE iGCSE Biology – 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
The Sun – The Principal Source of Energy in Biological Systems
Key Statement:
The Sun is the main (principal) source of energy input to all biological systems on Earth.
Why the Sun Is So Important:
Green plants use sunlight in the process of photosynthesis to make food (glucose).
This stored energy is passed on to herbivores (plant-eaters), and then to carnivores and omnivores.
Decomposers also get energy by breaking down dead organisms – which originally got their energy from the Sun too.
Green plants use sunlight in the process of photosynthesis to make food (glucose).
This stored energy is passed on to herbivores (plant-eaters), and then to carnivores and omnivores.
Decomposers also get energy by breaking down dead organisms – which originally got their energy from the Sun too.
🌱 How the Energy Flows:
- ☀️ Sunlight
- ⬇
- 🌿 Producers (plants) make food using light energy
- ⬇
- 🐾 Consumers (animals) eat plants or other animals
- ⬇
- 🦠 Decomposers break down waste and dead matter
Key Point to Remember:
Almost all energy that living things use to grow, move, and survive comes originally from the Sun.
Almost all energy that living things use to grow, move, and survive comes originally from the Sun.
🧾 Real-Life Examples:
- Plants make their own food from sunlight → photosynthesis
- Humans eat plants or animals → energy came from plants → which got it from the Sun
- Even fuels like coal and oil are ancient stored energy from the Sun (via plants)
Flow of Energy Through Living Organisms
☀️ 1. Energy From the Sun
- The Sun is the main source of energy for all life on Earth.
- Green plants (producers) capture light energy during photosynthesis.
- They convert it into chemical energy stored in glucose.
🌱 2. Chemical Energy in Organisms
- The chemical energy in plants is passed to herbivores when they eat plants.
- Then to carnivores and omnivores when they eat other animals.
- This energy transfer continues through food chains and food webs.
Energy moves through:
Sun → Plants → Herbivores → Carnivores → Decomposers
Sun → Plants → Herbivores → Carnivores → Decomposers
🔚 3. Loss and Transfer to the Environment
- At every step, some energy is lost as heat (mainly during respiration).
- Energy is also lost through movement, growth, excretion, and body heat.
- Eventually, all energy is either used or released into the environment as heat and waste.
🔄 4. Decomposers and Final Energy Flow
- When organisms die, decomposers like fungi and bacteria break them down.
- This releases the remaining chemical energy back into the environment as heat and nutrients.
🧠 Key Summary:
Energy flows in one direction – from the Sun to producers, through consumers, and finally to the environment as heat.
It is not recycled, unlike nutrients.