Think about it…
1
When humans cut down trees in forests, trees are
depleted. What are other effects of this activity?
Fish
• Fish from the sea is one of our
food sources.
• When the fish in the sea
cannot reproduce fast enough
to replace those that we catch,
the population of fish will
decrease.
• The negative impact is that
some fish become
endangered or do not exist
anymore.
Depletion of natural resources
2
• We clear large areas of forests by burning or cutting down
trees to make more space for farming or housing.
• These activities lead to deforestation which has a very
negative impact on the environment.
Deforestation
3
• When trees are cut down in huge numbers, habitats of
organisms are destroyed.
• These organisms, especially their young, become more
exposed to danger and die more easily as they lack
shelter and food.
Deforestation
4
• As trees are cut down, the soil on the ground becomes
more exposed to the Sun.
• The ground becomes dry as the water in the ground
dries up very quickly and there is less rain.
• The drier soil on the top of the ground also gets blown
away more easily by the wind.
• As a result, the ground becomes less fertile for farming
or growing trees.
Deforestation
5
• There are fewer trees to hold onto
the soil on the ground.
• Thus, when rain falls, it can
remove and wash away the soil
easily, causing soil erosion.
• When the soil is washed into
water bodies, such as rivers and
lakes, the water becomes
muddy and polluted.
• This causes plants living in
these water bodies to die
because they are not able to trap
light to make food.
Deforestation
6
• As trees are burnt, thick smoke and ashes produced
contribute to air pollution and causes haze.
• Smoke and haze can cause irritation to the eyes, breathing
difficulties and damage to the respiratory system.
Deforestation
7
• Burning down trees produces carbon dioxide.
• The amount of carbon dioxide in the air increases as there
are fewer trees to take in carbon dioxide.
• Carbon dioxide is a greenhouse gas, which traps some
of the Sun’s heat on the Earth.
• Too much carbon dioxide can cause too much heat to be
trapped on the Earth.
• This raises the temperature on the Earth’s surface, leading
to global warming.
Deforestation
8

Deforestation

  • 1.
    Think about it… 1 Whenhumans cut down trees in forests, trees are depleted. What are other effects of this activity?
  • 2.
    Fish • Fish fromthe sea is one of our food sources. • When the fish in the sea cannot reproduce fast enough to replace those that we catch, the population of fish will decrease. • The negative impact is that some fish become endangered or do not exist anymore. Depletion of natural resources 2
  • 3.
    • We clearlarge areas of forests by burning or cutting down trees to make more space for farming or housing. • These activities lead to deforestation which has a very negative impact on the environment. Deforestation 3
  • 4.
    • When treesare cut down in huge numbers, habitats of organisms are destroyed. • These organisms, especially their young, become more exposed to danger and die more easily as they lack shelter and food. Deforestation 4
  • 5.
    • As treesare cut down, the soil on the ground becomes more exposed to the Sun. • The ground becomes dry as the water in the ground dries up very quickly and there is less rain. • The drier soil on the top of the ground also gets blown away more easily by the wind. • As a result, the ground becomes less fertile for farming or growing trees. Deforestation 5
  • 6.
    • There arefewer trees to hold onto the soil on the ground. • Thus, when rain falls, it can remove and wash away the soil easily, causing soil erosion. • When the soil is washed into water bodies, such as rivers and lakes, the water becomes muddy and polluted. • This causes plants living in these water bodies to die because they are not able to trap light to make food. Deforestation 6
  • 7.
    • As treesare burnt, thick smoke and ashes produced contribute to air pollution and causes haze. • Smoke and haze can cause irritation to the eyes, breathing difficulties and damage to the respiratory system. Deforestation 7
  • 8.
    • Burning downtrees produces carbon dioxide. • The amount of carbon dioxide in the air increases as there are fewer trees to take in carbon dioxide. • Carbon dioxide is a greenhouse gas, which traps some of the Sun’s heat on the Earth. • Too much carbon dioxide can cause too much heat to be trapped on the Earth. • This raises the temperature on the Earth’s surface, leading to global warming. Deforestation 8

Editor's Notes

  • #2 Have pupils analyse the above situation and suggest the effects. Ask pupils to explain and elaborate on the impact of this human activity on organisms. Logging: https://commons.wikimedia.org/wiki/File:Exploitation_forestiere.JPG
  • #3 Lead pupils to talk about the interdependence between organisms in a community and how overfishing or overhunting can affect the eco-balance in the community. Fishing: https://commons.wikimedia.org/wiki/File:Fish_catching_in_Laos.jpg
  • #4 Enrichment: The cutting down and burning of forests is also known as slash-and-burn. Clearing of jungle: https://commons.wikimedia.org/wiki/File:Lacanja_burn.JPG
  • #5 Moose and calf: https://commons.wikimedia.org/wiki/File:Moose_and_calf_animals_in_forest.jpg
  • #6 Dry land: https://commons.wikimedia.org/wiki/File:Dry_creek_bed,_Quivira_Refuge_%288426146245%29.jpg
  • #7 Have pupils recap how organisms living in the water will be affected if the plants in the water where they live in die. Muddy water: https://commons.wikimedia.org/wiki/File:Dirt_and_Mud_005_-_Muddy_Water.jpg
  • #8 Haze: https://commons.wikimedia.org/wiki/File:Aerial-photo-heavy-haze.jpg