Unit Three Flashcards
What is exponential growth?
Increase in number or size, at a constant rate. Eg. Pandemic at first no one was sick, then everyone at once
What is carrying capacity?
the number of people, other living organisms, or crops that a region can support without environmental degradation
What is the rule of 70?
number of years to double = 70/annual growth rate
What led to fast growth?
1) moved from hunting to farming (agrarian)
2) Developed sewer system (food separate from waste)
3) Medicine and vaccines
Stage one of fast growth…
HUNTING AND GATHERING
- Food was not reliable
- Populations fluctuate like the hare/lynx graph. When game or plants were abundant, population increased; if food was scarce population
- Large area of land necessary to support small number of people - earth carrying capacity low
- In order for population to increase a increase in reliable and abundant food source necessary
Stage two of fast growth…
AGRICULTRE REVOLUTION
- Resulted in food surplus*
- Increased carrying capacity and provided people with time
- Only reason we are sitting here is because we are based upon the agrarian calendar
- Don’t have to keep moving can stay in one spot → civilizations form
What did agriculture revolution lead to?
Less fear of starvation
Other activities due to time
Better life expectancy
Improved health
Introduce trade
Beijing writing
Job specialization
What are the two population growth patterns?
1) J Curve
Unlimited environment
No limits to growth
2) S Curve
Pressure on growth (competition, predators) causing rates to slow
Stage 3 of fast growth…
CARRYING CAPACITY
- estimate of # of people who can live in an area and be supported (depends on ecological footprint and recourse consumption)
How do we continue to grow carrying capacity?
things like GMOs and golden rice provide food to people and allow them to thrive
What is overshoot?
Longer the consumption of over the carrying capacity
Degrades carrying capacity
Thomas Malthusian
Malthusian growth model, an exponential formula used to project population growth. The theory states that food production will not be able to keep up with growth in the human population, resulting in disease, famine, war, and calamity.
The ideas that malthus had are very interesting because of the threats that climate change is posing to us. Yes we have increased technology, medicine, etc. but will that come to a cost. Maybe Malthus is right and we are to early to see it.
Population is affected by what 4 factors?
Birth
Death
Immigration (moving permanently to a new country)
Emigration (moving permanently from one’s native country)
Birth and immigration have a positive effect on a population
Death and emigration have a negative effect on a population
Final population formula
Final population = starting pop + births - deaths + imigrantions - emigration
Birth rate formula
Birth rate = births / population x 1000
death rate formula
Death rate = deaths/population x1000
immigration rate
Imigration rate = immigrants/population x1000
immigration rate
Emigration rate = emigrants/population x1000
Natural increase rate
Natural increase = birth rate - death rate
Net migration rate
Net migration rate = immigration rate - emigration rate
Population growth rate
Population growth rate = natural increase rate + net migration rate
doubling rate
Doubling time = 70/population growth rate
What is causing huge fertility decrease?
caused by woman success going to school and getting jobs, want less children
what is dependancy ratio?
Measure used to indicate the ratio of people in the “dependant” ages (under 15 and over 65) per 100 people in “economically productive” ages