Natural Systems Flashcards
What is a system in geography?
A system is a model that simplifies the complexity of the world for understanding by showing its components (stores) and how they are linked through flows (transfers).
What are the three main types of systems? (3 things)
- Isolated System – No inputs or outputs (rare in nature).
- Closed System – Inputs and outputs of energy but not matter (e.g., water or carbon cycle).
- Open System – Inputs and outputs of both energy and matter (e.g., drainage basin system).
What is dynamic equilibrium in a system?
A state where inputs and outputs are balanced, keeping the system stable over time.
What is feedback in a system? (2 things)
• Negative Feedback – Stabilises the system and maintains equilibrium.
• Positive Feedback – Disrupts equilibrium and causes further change.
Give an example of negative feedback in a system.
Increased cloud cover from higher evaporation rates reflects more sunlight, cooling the atmosphere and reducing evaporation.
Give an example of positive feedback in a system.
Melting ice reduces surface reflectivity, absorbing more heat and causing more ice to melt.
What is the water balance?
The balance between water input (precipitation) and output (evaporation and river discharge) in a drainage basin system.
How can dynamic equilibrium in the water cycle be disrupted? Mention 3 things
• Increased inputs: Heavy rainfall, flooding, human activity.
• Decreased outputs: Drought, human activity (e.g., water abstraction).
• Climate change: Alters precipitation and evaporation patterns.
Why is the global water cycle considered a closed system?
No water enters or leaves the Earth; it only moves between stores.
Why is a drainage basin an open system?
Constantly receives inputs from outside sources (precipitation) and it released outputs like water flowing out to the sea through the river.
