Ecosystems (Copy)
9.1 Ecosystems – Cheat Sheet
Key Definitions
| Term | Definition |
|---|---|
| Ecosystem | A community of living organisms (biotic) interacting with non-living environment (abiotic). |
| Population | All individuals of one species living in an area. |
| Community | All populations of different species living together in an area. |
| Habitat | The place where an organism lives. |
| Niche | The role of an organism in an ecosystem (feeding, reproduction, interactions). |
Components of an Ecosystem
| Component | Examples |
|---|---|
| Biotic (Living) | Producers (plants), Consumers (herbivores, carnivores, omnivores), Decomposers (fungi, bacteria) |
| Abiotic (Non-living) | Temperature, light, pH, oxygen, salinity, humidity, water availability |
Biotic Interactions
| Interaction | Description | Example |
|---|---|---|
| Competition | Organisms compete for resources | Plants competing for light |
| Predation | Predator eats prey | Lion hunting zebra |
| Pollination | Plants depend on animals to transfer pollen | Bees pollinating flowers |
Photosynthesis
- Equation:
Carbon dioxide + Water → Glucose + Oxygen
(with light + chlorophyll) - Importance: Produces energy-rich food (glucose) and oxygen for life.
Energy Flow
| Concept | Description |
|---|---|
| Food Chain | Simple transfer of energy (e.g., Grass → Rabbit → Fox). |
| Food Web | Complex network of interconnected food chains. |
| Trophic Levels | Producer → Primary consumer → Secondary consumer → Tertiary consumer. |
Ecological Pyramids
| Type | Description |
|---|---|
| Numbers Pyramid | Shows number of organisms at each trophic level. |
| Energy Pyramid | Shows energy loss at each trophic level (only ~10% passed on). |
Respiration
- Equation:
Glucose + Oxygen → Carbon dioxide + Water + Energy - Importance: Releases energy for growth, movement, repair, and survival.
Carbon Cycle
| Process | Role |
|---|---|
| Photosynthesis | Plants absorb CO₂ → glucose. |
| Respiration | Organisms release COâ‚‚. |
| Decomposition | Dead organisms decomposed → CO₂ returned. |
| Combustion | Fossil fuels burned → CO₂ emitted. |
Quick Pointers
- Energy flow = one way (sun → producers → consumers → decomposers).
- Nutrients like carbon are recycled (via cycles).
- Balance of photosynthesis & respiration regulates COâ‚‚/Oâ‚‚ in atmosphere.
Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Environmental Management Full Scale Course