Ecosystems as Open Systems
Definition
Ecosystem
An ecosystem is an ecological unit consisting of living organisms (biotic components) interacting with their physical environment (abiotic components).
- Imagine a forest.
- Sunlight streams through the canopy, water flows through streams, and animals move in and out.
- This dynamic environment is an open system, where both energy and matter can enter and exit.
Open vs. Closed Systems
Open Systems
Definition
Open system
A system that exchanges both energy and matter with its surroundings.
- An open system is a system where both energy and matter can be exchanged with the surroundings.
- Ecosystems are open systems because they interact with their environment, receiving inputs like energy from the sun and nutrients from the soil, and producing outputs like waste products and heat.
A forest ecosystem receives sunlight (energy) and nutrients (matter) from the soil, and it also exports oxygen, water vapor, and organic waste into the environment.
Closed Systems
Definition
Closed system
A system that only exchanges energy with its surroundings, not matter.
- A closed system is one where only energy can enter or exit, but matter is contained within the system.
- In a closed system, there are no exchanges of material with the environment, but energy can still flow in and out.
- A sealed terrarium is a closed system because it does not exchange matter with its environment.
- The plants within it can still absorb sunlight (energy) and release oxygen, but the nutrients and water within the terrarium are recycled internally.
- Ecosystems are rarely completely closed.
- Even isolated environments like caves rely on external inputs, such as water or nutrients.
Energy Flow in Ecosystems
- Sunlight is the primary energy source for most ecosystems.
- Producers (like plants) convert sunlight into chemical energy through photosynthesis.
