AQA GCSE Biology

Revision Notes

7.3.2 Waste Management

Human Population

  • Human population growth globally has been increasing exponentially for the last 150 years

 

Human population growth, IGCSE & GCSE Biology revision notes

Human population growth is growing exponentially

  • There are many reasons for this exponential growth, including:
    • Improved technology leading to an abundance of food = rapid increase in birth rate
    • Improved medicine, hygiene and health care = decrease in death rate
  • Rapid growth in the human population and an increase in the standard of living mean our negative effect on the environment is also increasing
  • As increasingly more resources are used to sustain the growing human population, more waste is produced and more pollution is created
  • Unless waste and chemical materials are properly handled, pollution will continue to be created

Pollution

Water pollution 

Sources of water pollution and their effects

Sources of water pollution and their effects table 1, downloadable IGCSE & GCSE Biology revision notes

Bioaccumulation and biomagnification of a pesticide, downloadable IGCSE & GCSE Biology revision notes

Biomagnification and bioaccumulation of a pesticide in an aquatic ecosystem

 

Eurtrophication, IGCSE & GCSE Biology revision notes

Sequence of events causing eutrophication in lakes and rivers

Land pollution 

Sources of land pollution and their effects

Sources of land pollution and their effects table 2, downloadable IGCSE & GCSE Biology revision notes

Air pollution 

Sources of air pollution and their effects

_Sources of air pollution and their effects table 3, downloadable IGCSE & GCSE Biology revision notes

How acid rain is produced, downloadable IGCSE & GCSE Biology revision notes

How air pollution leads to acid rain

Exam Tip

Water pollution from sewage and water pollution from fertiliser runoff have the same end result (increase in decomposing bacteria leading to a decrease in dissolved oxygen and death of aquatic organisms) but they do not arrive at this point in the same way.

You need to learn both and be aware of the differences between them. A common misconception is that sewage pollution also causes growth of water plants and algal blooms – this is very rarely the case, only runoff of fertiliser does this.

Author: Jenna

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.
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