A Growing Human Population

Societies

1. Hunter-Gatherers Small populations (25-30 people) Widely dispersed Obtained their food by hunting, fishing and gathering wild plants Used hand tools

Nomadic according to availability of plants and animals Used only what they needed for survival Caused very little damage to the environment

2. Agricultural Society 10,000 years ago people began to raise animals and grow crops Occurred at many different places at about the same time

Allowed people to produce more food than gathering wild plants Used horses and ox drawn equipment Began creating their own ecosystems Increased the carrying capacity of the land human population began to grow larger families advantageous

3. Industrial Revolution

Industrial Revolution - Raised standard of living Goods produced in factories Tractors used in agriculture Required large amounts of fossil fuels Improved sanitation Improved nutrition People could shop for their food

Most people able to survive through childhood to reproduction Improved medical care Decrease in death rates is the biggest factor contributing to the explosive growth during the last 200 years Most people able to survive through childhood to reproduction Use of technology may allow the human population to surpass the Earth’s carrying capacity

Human Population Continues to Grow

Human population grew very slowly for thousands of years, but began rapid growth in the 1800’s Human population doubled between 1800 and 1930 1975 the human population reached 4 billion, and exceeded 5 billion by 1987

Population Histograms

Population Histograms Graph that shows data frequency x-axis: % of population right females left males y-axis: birth year or age y males females age x 50 50 % of population

Growing Population More births than deaths Pyramid shape Developing countries

Stable Population Births = Deaths Developed Countries Column shape

Declining Population More deaths than births Indented at the bottom Developed Countries

Demographic Transition In 2010 the world’s population surpassed 7 Billion Today, the world’s population is over 7.3 billion 7,345,000,000 - World 324,292,000 - U.S. Human population continues to grow, but growth has slowed due to lower birth rates in most parts of the world most of the increase in human population is occurring in the developing countries

Birth and death rates are both high in preindustrial societies and results in slow, if any, population growth Improved health care increases a population: higher birth rates and longer life span

Birth rates fall until they roughly equal death rates and population growth slows and stops marry later have children later birth control parents realize children are likely to grow to adulthood consider the number of children they can care for children recognized as an expensive responsibility