GCSE Biology - The Environment

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  • The Environment

Humans Need:

  • Housing - Building can destroy animal and plant habitats.
  • Food - Converting wild habitats into farmland reduces biodiversity.
  • Alternative Energy - Development of tidal barrages and power stations can alter/destroy natural habitats.

Problems due to the increasing population:

  • Less Food - More food is needed then.
  • More Pollution(Sewage)
  • Deforestation - To clear forests for agricultural land to build houses and to create farms.

Intensive Farming(Battery-Farming, uses pesticides, fertilisers):

Advantages:  

  • Cheaper Produce
  • Higher crop yield(from using fertilisers)
  • Reduces global hunger.

Disadvantages:

  • Stress on animals.
  • Pesticides can pass into human food chains and accumulate reaching toxic levels.(Bioaccumulation)
  • Pesticides cost money.

Extensive Farming(Organic Farming), uses crop rotation, weeding, manure.

Advantages:

  • Chemical Free.(Pesticide Free)
  • Sustainable.

Disadvantages:

  • Higher cost for produce.
  • Lower crop yield.
  • Labour Intensive.

Intensive Farming - Using Pesticides:

  • Upsets food chains - Kills useful insects, this removes the primary consumer, leaving the secondary consumer with less food.
  • Bioaccumulation - Pesticides(e.g DDT), can become more concentrated along the food chain, reaching toxic levels.

Fertilisers:

  • We use fertilisers to replace lost nutrients in the soil.(e.g Nitrates, Phosphates, Pottasium).
  • Nitrates(NO3-) - Better crop growth.
  • Phosphates(P) - Higher crop yield.
  • Potassium(K) - Builds stronger roots.
  • Leaching - Nitrates in the soil are very soluable in water, as it rains the nitrates in the soil dissolve into the rain water and are carried to deeper parts of the soil.
  • Eutrophication - Enrichment of rivers and streams by excess nutrients.(e.g. from fertilisers)

Nutrient Cycle:

1) Crops…

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