Chapter 19: Effects of human activity on the ecosystem

Deforestation

Is the cutting of trees.

• ^^Reasons:^^
  • Urban development
  • Cultivation
  • Grazing
  • Timber
  • Fibres
• ^^Effects of deforestation:^^
  • Soil erosion
  • Flooding
  • Desertification:
  • Loss of habitats.
  • Extinction of species.
  • Loss of robust wild species of plant.
  • Imbalance b/w O2 and CO2 concentration in air.
  • Climatic changes.

Pollution

• ^^Pollutants^^:
  • Sulphur dioxide and nitrogen oxides - leads to acid rain and smog.
  • Lead - is poisonous if accumulated with consumed food.
  • Carbon monoxide - forms carboxyhemoglobin in blood.
  • Carbon dioxide - greenhouse effect.
  • Chlorofluorocarbons (CFC’s) - damage ozone layer.
• ^^Causes^^
  • Exhaust fumes from motor vehicles.
  • Chimney fumes.
  • Burning of garbage.
• ^^Ways of reducing^^
  • Use catalytic converters in cars.
  • Less use of cars.
  • Use filters or scrubbers on chimneys to remove sulphur dioxide.
  • Use of less fossil fuels in factories.
  • Use of alkalis to neutralize acidic waste products from factories before they are released to environment.
  • Use ozone - friendly products.
• Water pollution
  • ^^Causes^^:
  • Sewage
  • Inorganic waste
  • Fertilizers - eutrophication
  • Pesticides
  • Insecticides
  • Herbicides

Conservation

• ^^reasons^^
  • Ensure protection of plant and animals.
  • Maintenance of stable and balanced ecosystem.
  • Ensure conservation of marine life + tropical forests + natural scenery.
  • Scientific value.
• ^^Measures^^
  • Laws that prevent tree hunting and human activities that harm ecosystem.
  • Educate youth.
  • On fishing grounds - ban use of large nets + regulating size of ships + limiting period of fishing + banning harvesting endangered species + harvesting months.
• ^^Why is recycling necessary^^
  • Reduces waste disposal.
  • Reduces pollution.
  • Treatment of sewage saves water.
  • Saves energy and money.