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WALT – Explain how we can use organisms to monitor pollution levels. Pollution Indicators. What are pollution indicators?. The organisms in polluted water tell you that there is something wrong. Examples of pollution indicators.
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WALT – Explain how we can use organisms to monitor pollution levels Pollution Indicators
What are pollution indicators? • The organisms in polluted water tell you that there is something wrong.
Examples of pollution indicators • Lichens are plants that grow in exposed places such as rocks or tree bark. • Air pollutants dissolved in rainwater, especially sulfur dioxide, can damage lichens, and prevent them from growing. • This makes lichens natural indicators of air pollution. For example:
Examples of pollution indicators • Some invertebrates like mayfly nymphs and rat-tailed maggots, are able to survive in polluted waters
This is what happens when a stream or river becomes polluted • Pollutant is added, which kills some living things. • Micro-organisms decompose them, they respire and use up the oxygen • Lack of oxygen kills other organisms, but a few species stay alive • As the water flows, oxygen levels gradually increase • Other living things recover too.
Sulphur dioxide, cities and lichens A scientist surveyed the distribution of lichens. She counted the number of different species that grew on tree trunks at various distances from the centre of a polluted city. She also measured how much sulfur dioxide there was in the air.
Sulfur dioxide, cities and lichens Think : Is the data continuous or discreet? What are you : changing? (x-axis) Measuring? (y-axis)
Graph Questions • What is the relationship between the number of species of lichen and the distance from the centre of the city. • Name one invertebrate that can survive where there is little oxygen and another one that needs normal clear water to live in
How you will be graded • Graph : 4 marks • 1 for scale • 1 for well labelled axes • 1 for plotting • 1 for line of best fit • Question 1 = 2 marks • Question 2 = 2 marks