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