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  • Created by: Dharshini
  • Created on: 08-05-11 17:41

Increase in human population causes the following problems:

  • Land used for more buildings, growing crops, landfill sites, roads and rearing animals. As a result, habitats and food webs are being disruptted leading to a reduction in biodiversity.
  • Improper dumping of waste
  • Raw materials are being used up quickly.
  • Over fishing is resulting in fish stock being reduced.
  • Increasing amounts of industries and domestic waste are being produced. This results in more land fill sites being needed resulting in large areas of landbeing unsuitable for plant and animal life.

Water Pollution - Water can be polluted in many different ways eg, with toxic chemicals from factories, raw sewage and fertilisers.

Sewage and fertilisers can be responsible for increasing the amount of mineral ions in rivers, lakes etc, et nitrates,

Nitrates are needed byplants to make proteins for growth. As a result of incresing nitrate levels in the water, the following can occur:

  • Algae in theh water reproduce rapidly so they use the extra nitrates to make proteins for growth.
  • The algae form a layer over the surface of the water (algae bloom) which prevents light from entering.
  • Plants, living under the water surface, die due to the lack of light for photosynthesis.
  • Bacteria in the water decomposes the dead plants. As a result of them having food, they increase in number.
  • The extra bacteria use up more oxygen from the water for respiration.
  • The oxygen level in the water decreases resulting in the death of animals such as fish and insects as they have



These notes describe problems in the environment caused by the human population. They would be useful for any GCSE Biology specification that entails a study of ecology. Summarising  the information in a Mind map with colour and images to stimulate memory would be a useful exercise.

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