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HUMAN POPULATION
Growth and Control
Demography
The study of populations, specifically human population
Demographers study the size and makeup and compare countries and make predictions of the future
Divided into 2 groups Developed – higher income, slow growth,
strong social support Developing – lower incomes, agricultural
based economy, fast growing
Human Population Over Time Human population has grown
exponentially over time beginning in the 1800s...why?
Forecasting Population Size: Age Structure
Age Structure – the spread of ages in a specific population at a certain time
3 types of population pyramids
Rapid Growth
Countries with more young people Example: Nigeria
Slow Growth
Countries with fewer young people Example: USA
Zero or Negative Growth
Countries that have much fewer births Example: Germany
Forecasting Population Size: Survivorship
Survivorship –percentage of members of a group that are likely to survive to a given age
3 types of survivorship curves
Type I
Death late in life
Type II
Death steady throughout life
Type III
Death early in life
Forecasting Population Size: Fertility Rates
Fertility rate - the number of babies born each year per 1000 women
Total fertility rate – average number of children a woman gives birth to in her lifetime Currently – 2.1
Forecasting Population Size: Migration
Migration – movement of individuals between areas Immigration – into an area Emigration – out of an area
Declining Death Rates
Why are deaths decreasing? Improved medicine Better access to education Better food Cleaner water Safe sewage disposal
Changing Population Trends
CHANGING POPULATION TRENDS
Infrastructure
The basic facilities and services that support a community, such as Water supplies Sewage lines Power plants Roads Subways Schools Hospitals
Problems of Rapid Growth
Use resources faster than the environment can renew them unless they come from somewhere else
What resources do you think are most critically affected by rapid growth? Vegetation Water Land
A Shortage of Fuelwood
In areas where trees don’t drop dead branches to use as fuel, people begin to cut down trees reducing the number of trees left each year to use, ruining vegetation.
A supply of fuel allows people to do what? Boil water to drink Cook
Unsafe Water
Results in... Bad drinking water Dirty water to wash with No sewage disposal Many countries cant expand their water
systems as fast as they are growing
Impacts on Land
Growing populations have a shortage of arable land, which is land that can be used to grow crops
Much of the world’s population is undergoing urbanization, building and living in urban areas instead of rural