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Human Population


HUMAN POPULATION Noadswood Science, 2012 – PowerPoint PPT presentation

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Title: Human Population

Human Population
  • Noadswood Science, 2012

Human Population
  • To understand the impact of rapid growth in the
    human population

Developing Developed
  • Look at the following a recent scene from the
    Glastonbury festival and a shanty town in South
  • What issues are involved with this many people?

Developing Developed
  • In a given area if the population becomes this
    vast there is a huge strain on resources needed
    space / shelter food water (and mates)
  • There is also a great strain on removal of waste
  • This impacts not only human populations, but any
    surrounding flora and fauna

Human Population Projection
  • Human beings compete with other living things for
    resources and space as the worlds population
    continues to increase, and standards of living
    improve, there is serious danger of a permanent
    change to the global environment
  • Human activities have led to the pollution of the
    environment, and a reduction in the amount of
    land available for other animals and plants,
    which makes it difficult for some species to
  • There is a need to achieve a level of development
    that also sustains the environment for future

Human Population Projection
  • Like all living things, humans exploit their
    surroundings for resources before the beginning
    of agriculture about 10,000 years ago, small
    groups of humans wandered across large areas,
    hunting and gathering just enough food to stay
  • Population numbers were kept low because of the
    difficulty of finding food
  • The development of agriculture led to a
    population explosion that has accelerated
    enormously during the past 500 years unlike
    other species, humans can adapt to and survive in
    almost all habitats and climates

Human Population Projection
  • Using the data in the table below plot a graph
    showing how the human population has changed over
    the last 10000 years -

Year Human Population Numbers (Thousands)
8000 BCE 5000
6000 BCE 10000
4000 BCE 20000
2000 BCE 35000
0 200000
2000 CE 6000000
Human Population Projection
  • Human population graph over the past 10000
    years -

Human Population
  • In the last 200 years or so the human population
    has grown very quickly why?
  • We can grow more food
  • We can cure and prevent illness or disease
  • We have no natural predators
  • Standard of living has improved (electricity,
    fuel, heat, cars etc)

Standards Of Living
  • People in the developed world enjoy a high
    standard of living, with abundant food, cars and
    comfortable housing
  • People in the developing world have a lower
    standard of living, but many countries are
    catching up quickly
  • Strains on the global environment include -
  • Non-renewable energy resources (e.g. coal, oil
    and natural gas) are being used up rapidly
  • Raw materials are being used up rapidly
  • More waste is being produced
  • More pollution is being caused

  • Pollution is the addition of substances to the
    environment that may be harmful to living
  • Population growth and increases in the standard
    of living cause more waste to be produced If
    this waste is not handled correctly, it leads to
  • Pollution can be categorised into the following
  • Land pollution
  • Water pollution
  • Air pollution

Land Pollution
  • Most rubbish is buried in landfill sites and not
    all of it comprises safe materials even common
    household items can contain toxic chemicals such
    as poisonous metals (many smoke alarms contain
    radioactive americium)
  • Industrial waste is also discharged onto the land
    many farmers apply pesticides to improve their
    crops, but these can damage living things (toxic
    chemicals can be washed from the land into
    rivers, lakes and seas causing eutrophication)

Eutrophication in the Caspian Sea (turbidity in
Water Pollution
  • Water pollution is caused by the discharge of
    harmful substances into rivers, lakes and seas
  • Many aquatic invertebrate animals cannot survive
    in polluted water, so their presence or absence
    indicates the extent to which a body of water is

Pollutant Typical Effect
Fertilisers Damage to aquatic ecosystems
Sewage Damage to aquatic ecosystems and humans
Toxic chemicals Damage to aquatic ecosystems and humans
Air Pollution
  • The most common source of air pollution is the
    combustion of fossil fuels

Pollutant Effect
Smoke Deposits soot on buildings and trees, causing them damage permeates the air, making it difficult for living creatures to breathe
Carbon monoxide Poisonous gas
Carbon dioxide Greenhouse gas that contributes to global warming
Sulfur dioxide Contributes to acid rain
  • Humans have been cutting down trees for thousands
    of years to clear land for farming and building,
    and for wood to use as a fuel or building
  • Forestry is sustainable as long as forests are
    allowed to replace themselves, or are replanted
    after felling, but often this is not done the
    result is that the worlds forests are steadily
  • Crops being grown for biofuels, based on ethanol,
    is now also playing a major part in deforestation

  • The worlds forests have changed greatly over the
    last 10000 years

  • The worlds forests have changed greatly over the
    last 10000 years

  • Deforestation leads to -
  • Forest habitats being destroyed
  • Soil erosion increasing, which causes barren
    land, flooding and land slides
  • Atmospheric pollution is caused when forests are
    cleared by burning trees
  • Deforestation also leads to a loss of
    biodiversity this refers not only to the number
    of different species, but also to all the
    variations within and between species, and all
    the differences between the habitats and
    ecosystems that make up the Earths biosphere

  • The loss of forests reduces biodiversity and we
    run the risk of losing organisms that might have
    been useful in the future - for example as
    sources of new medicines
  • There is also a moral responsibility to look
    after the planet and its resources

Global Warming
  • The atmosphere is a thin layer of gases,
    surrounding the Earth
  • Certain gases in the atmosphere trap heat,
    reflecting it back to the Earths surface,
    warming it
  • This is similar to the glass in a greenhouse,
    which traps heat inside it (trapping of heat by
    the Earths atmosphere is known as the greenhouse
  • Without this atmosphere the Earth would be too
    cold for life to exist