Population/ Resources / Pollution Model Flashcards
What does the population , resource and pollution model represent?
Human- environment interaction.
Systems approach
Sustainable solutions - controlling population - less demand for resources - reduce levels of pollution
Negative/ positive feedback
What does model show
Population acquires resources from environment.
This will alter existing biotic/ abiotic conditions of ecosystem.
Resources extracted from environment are utilised and it can lead to pollution of land/ water/ atmosphere
Example of model
Open cast coals mines damage/ destroy wildlife habitat = deforestation/ soil erosion which can pollute nearby streams.
Coal used in power stations to generate electricity are put into cars. Conversion of raw materials into energy results in pollution.
Cross medium contamination
When pollution moves from one environmental medium to another.
Acid rain is an atmospheric pollutant but when it falls from sky, acid contaminates forests / waters
What does negative feedback ensure
System is held in a more stable equilibrium
Why do populations use negative feedback loops
To keep plant / animal populations without carrying capacity of environment
Why do the negative feedback loops from resource use and pollution show great concern ?
Eg continued soil erosion from over grazing would lead to decline in food production which would have devastating effects on human population.
Already seen in sub Saharan Africa.
The negative feedback levels out problem and in many cases there will be a decline in standard of living as fewer resources available
What does the S curfew and PRP model suggest
Negotiate feedback will be consequence of pop growth.
As pop nears/exceeds carrying capacity then negative feedback will mean that there is an insufficient resources and death rates will overtake birth rates causing pop decline back to stable equilibrium
Agriculture and population
Togther as a positive feedback spirals.
Pop growth has led to increase in agricultural yields and production through technology -more population can be supported so pop growth continued at exponential rate
What will positive feedback eventually lead to ?
Serious issues/depletion.
Eventually in agriculture production, despite technology advances soils become depleted and carbon cycle is disruptions leading to instability.
Fossil fuel energy which has increased capacity to produce/ distribute food but create risk in global temps due to greenhouse gases.
This may mean reduced rainfall in places - drought - less crop production
