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