Using living things to tell us

levels of pollution

Activity 5 • Learning Intentions

• Give examples of sources of pollution and the ecosystems that they effect

• Explain the meaning of the term indicator species

• Give named examples of river indicator species and the level of pollution that they show.

• Describe how pollution effects river ecosystems

• Describe how different types of lichens show different levels of air pollution.

• Success Criteria

• I can contribute to a class discussion to demonstrate any knowledge I have on pollution

• I can write a few sentences to describe pollution in the river and species that allow the level of pollution to be assessed

• I have made ‘sewage in a bottle’ and understand the reason each component (ingredient) was added

• I can place indicator species into their preferred water environment

Living organisms can be used as indicators of pollution.

You need to understand two ways of identifying pollution.......

1. How Lichens are used as indicators of air pollution.

2. How invertebrate animals are used as indicators of water pollution.

Have you ever seen plants like this?

Where might you see them?

What are lichens? Lichens are similar organisms to algea or fungi. There are more than 1,700 species of lichen in Britain. Approximately 18,000 species of lichen have been described and identified worldwide.

Why are Lichens used as pollution indications?

Lichens absorb water and minerals from rainwater and directly from the atmosphere, over their entire surface area. This makes them extremely sensitive to atmospheric pollution. As a result, there are usually very few lichens around industrial centres and towns. Different lichen species vary in their tolerance to pollution and therefore make very good biological indicators of levels of atmospheric pollution.

Indicators of air pollution

Lichens are plants that grow in exposed places such as rocks or tree bark. Air

pollutants, especially sulphur dioxide, can damage lichens, and prevent them

from growing.

This makes lichens natural indicators of air pollution. For example:

In places where no lichens are growing, it's often a sign that the air is

heavily polluted with sulphur dioxide.

Green, bushy

lichens need really

clean air

crusty lichens can

survive in more

polluted air

‘leafy’ lichens

can survive a

small amount of

air pollution

Indicators of water pollution

Scientists can take samples of the invertebrate animals living in a

river to see if it is polluted.

Some invertebrates are able to live in polluted water and some are

not.

Indicator species – Invertebrate as indicator of water pollution

Rat tailed maggot Live in sewage polluted water

Flatworm Live in slightly polluted water

Fresh water shrimp Live only in fresh water

You can determine if the water is polluted by collecting a sample of suspected water and analysis the type of animals that are in the sample.

Indicators of water pollution

Polluted water – cloudy, smelly with low levels of oxygen

Invertebrates found: Not many different species. Mostly

worms and leeches.

Indicators of water pollution

Slightly polluted water – less cloudy and smelly, oxygen

levels rising.

Invertebrates found: more species: molluscs (snails),

some beetles.

Indicators of water pollution

Clean water – clear water, high levels of oxygen.

Invertebrates found: Many different species. Will begin to

find shrimps and mayfly larva which will not tolerate any

pollution.

Highly polluted Moderately polluted

No pollution

1. Why are lichens useful pollution indications? 2. Why will you not see many types of lichens growing around factories?

Why do you think fish be a good pollution indication?

Fish need oxygen to live in the water. Water pollution effects the oxygen level in the water. If the water is so polluted the oxygen levels will fall and fish will die. This is how fish are a good indicator or pollution.

List as many things as possible as to how you know if an area is polluted or not? What would you see or smell?

A scientist surveyed the distribution of lichens. She counted the number of

different species that grew on trees at various distances from the centre of a

polluted city.

Here are her results:

Distance to the

town centre (km)

0 1 2 3 4 5 6 7 8 9 10

Number of

different species

of lichen

0 1 2 6 8 10 30 44 51 56 56

1. What was her independent and dependent variables?

2. Explain fully the relationship between the number of species and the

distance from the centre of the city.

3. What do these results show about the levels of pollution as you get

further from the city centre? Explain how you know.

4. Can you see any errors that could have arisen in this investigation?