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Understand the Signs of Environmental Pollution

Worksheet Overview

QUESTION 1 of 10

Human activity has increased the levels of environmental pollution. Burning fossil fuels (coal, oil and gas) is the main source of pollution, as well as the use of chemicals such as CFCs. These activities have led to global warming (worldwide raised temperatures) and the depletion of the ozone layer in the Earth's atmosphere, which protects us from the Sun's harmful radiation.

 

Power station chimneys

 

When factories empty their waste into canals, water pollution takes place in connecting rivers and lakes.

 

Rubbish in a river.

 

This results in plants and animals dying in those areas. The effect can be seen not only in the organisms that live in the water but also in organisms that live on the land around the polluted water. The water may also be used for crops and human consumption, so you can imagine the problems that can be caused.

 

Indicator species are organisms that can be used to determine the levels of pollution:

 

Stonefly larvae can only live in clean water.

The water spine fly is very sensitive to pollution.

The alderfly cannot live in polluted water because it cannot tolerate low oxygen levels.

Mayfly larvae tolerate some pollution but not much.

The freshwater mussel is also semi-sensitive.

Damselfly larvae can live in water that is a bit polluted, but not much.

The bloodworm can tolerate a lot of pollution.

The rat-tailed maggot can also live in very polluted water.

The sludge worm can live in polluted water because it can cope with low oxygen levels.

The water louse can tolerate high levels of pollution too.

Lichen grows on trees and rocks -  it is not found in cities because pollution from cars kills it.

 

In exam questions, you will be given data about the organisms that live in different environments and the levels of pollution they tolerate. You would then have to work out the level of pollution.

 

Let's have a go at some questions now.

What is the main cause of pollution?

Animals

Burning fossil fuels

Indicator species

Tick the possible reasons for the increase in skin cancer cases worldwide in the last few decades.

More people want to get a tan because it is trendy

There are high levels of pollution

The ozone layer of the atmosphere has been depleted

The Sun's rays have become more harmful

The world's population has grown exponentially (more and more rapidly) since the 1950's, especially in the underdeveloped countries. Most of the pollution is caused in developed countries that have a lower population relative to the area they occupy.

 

What is a possible explanation for this?

There are countries like the USA that have a huge population

Developed countries have the financial resources to buy more fossil fuels

More children are being born to families in underdeveloped countries

Fishermen who live around a lake have found a large number of dead fish and not enough living ones. 

 

What could be the reason?

Some bigger fish killed them

The levels of pollution in the water increased

Fishermen caught them but then threw the dead ones back in the water

A river has a certain species of fish living in it in two areas. Area one is in the mountains where the river begins, and the other area is in a valley near a small village. Over the course of about a hundred years, this type of fish can no longer be found near the village.

 

Why do you think this might be?

It has been over-fished

It has become extinct

The water near the village is now polluted

A pond has bloodworms living in it, but no stonefly larvae. Is it polluted?

Yes

No

Water samples from a lake contain lots of different species.

 

Is it polluted?

Yes

No

Match the organisms to their level of sensitivity to pollution. 

 SensitiveTolerantSemi-sensitive
Water spine fly
Alderfly
Lichen
Rat-tailed maggot
Damselfly larva
Sludgeworm

In the table below, look at the species living in three samples of water and then decide which sample is from the most polluted environment.

 

Sample Animals Found
A

stonefly larva, water snipe fly, alderfly, mayfly larva

B

rat-tailed maggot, sludge worm, bloodworm

C

sludge worm, freshwater mussel, damselfly larva

A

B

C

Water samples

 

Sample Animals Found
A

stonefly larva, water snipe fly, alderfly, mayfly larva

B

rat-tailed maggot,  sludge worm, bloodworm

C

sludge worm, freshwater mussel, damselfly larva  

 

Here are the same samples again.

 

Suggest which water is from a fast-running stream.

A

B

C

  • Question 1

What is the main cause of pollution?

CORRECT ANSWER
Burning fossil fuels
EDDIE SAYS
The main cause of environmental pollution is the burning of fossil fuels such as coal, oil and gas, in cars and factories. This is the most common form of human pollution because we use it so much to get most of our energy.
  • Question 2

Tick the possible reasons for the increase in skin cancer cases worldwide in the last few decades.

CORRECT ANSWER
More people want to get a tan because it is trendy
The ozone layer of the atmosphere has been depleted
EDDIE SAYS
How did you get on with this one? More and more people spend hours in the Sun in order to get a tan, but depletion of the ozone layer has allowed more of the harmful radiation from the Sun to enter the atmosphere. The ozone layer stops most of the harmful rays from getting through - without this, we risk more people developing skin cancer.
  • Question 3

The world's population has grown exponentially (more and more rapidly) since the 1950's, especially in the underdeveloped countries. Most of the pollution is caused in developed countries that have a lower population relative to the area they occupy.

 

What is a possible explanation for this?

CORRECT ANSWER
Developed countries have the financial resources to buy more fossil fuels
EDDIE SAYS
Underdeveloped nations may need a lot of fossil fuels due to their high population, but have neither the resources to buy them nor the infrastructure to use them. On the contrary, people who live in developed countries use a massive quantity of fossil fuels - causing high levels of pollution.
  • Question 4

Fishermen who live around a lake have found a large number of dead fish and not enough living ones. 

 

What could be the reason?

CORRECT ANSWER
The levels of pollution in the water increased
EDDIE SAYS
Dead fish commonly means there has been waste of some sort dumped in the lake, which increases water pollution. There are many different ways we can spot the type of pollution that has been dumped and most of them involve looking at the living creatures in the environment.
  • Question 5

A river has a certain species of fish living in it in two areas. Area one is in the mountains where the river begins, and the other area is in a valley near a small village. Over the course of about a hundred years, this type of fish can no longer be found near the village.

 

Why do you think this might be?

CORRECT ANSWER
The water near the village is now polluted
EDDIE SAYS
How did you get on with this question? Don't worry if you chose option one because it was a sensible thought. The clue to the correct option here is that this activity is about pollution! The fish has not become extinct because it still lives in the river up in the mountains. If it had been over-fished, more fish would have still come down to the area in the valley. The most probable explanation is that the village has now developed into a big city and the water is polluted.
  • Question 6

A pond has bloodworms living in it, but no stonefly larvae. Is it polluted?

CORRECT ANSWER
Yes
EDDIE SAYS
Remember back to the list of indicator species in the Introduction? There it stated that stonefly larvae cannot live in polluted water so the absence of these creatures is a significant biological marker for pollution. On the other hand, bloodworms can live in polluted water.
  • Question 7

Water samples from a lake contain lots of different species.

 

Is it polluted?

CORRECT ANSWER
No
EDDIE SAYS
A healthy environment usually contains lots of different species. However, to be certain that the water was unpolluted, you would need to identify what type of species were living in it. There could be lots of pollution-loving animals in the water - so be careful here!
  • Question 8

Match the organisms to their level of sensitivity to pollution. 

CORRECT ANSWER
 SensitiveTolerantSemi-sensitive
Water spine fly
Alderfly
Lichen
Rat-tailed maggot
Damselfly larva
Sludgeworm
EDDIE SAYS
Remember, the Introduction is always there if you need to check up on some information. Here's the correct results: The water spine fly is very sensitive to pollution. The alderfly cannot live in polluted water, because it cannot tolerate low oxygen levels - so it is sensitive too. Lichen grows on trees and rocks and is not found in cities where pollution from cars can kill it. So it is sensitive too. The rat-tailed maggot can live in very polluted water, so it is tolerant. The damselfly larva can live in water that is a bit polluted, but not much - so it is semi-sensitive. Finally, the sludgeworm can live in polluted water, because it can cope with low oxygen levels - so it is tolerant. Quite a list there - try to remember some of them even if there are too many to actually learn.
  • Question 9

In the table below, look at the species living in three samples of water and then decide which sample is from the most polluted environment.

 

Sample Animals Found
A

stonefly larva, water snipe fly, alderfly, mayfly larva

B

rat-tailed maggot, sludge worm, bloodworm

C

sludge worm, freshwater mussel, damselfly larva

CORRECT ANSWER
B
EDDIE SAYS
You need to use your list of indicator species again here. The species found in sample A are all ones that are sensitive to pollution, so it suggests that this sample is pretty clean. Sample C has several species that can cope with polluted water, but it also contains fresh water mussels which are semi-sensitive , so we know the water must be pretty good. So, we know the correct answer is Sample B which contains no species that tolerate pollution, so it is the most polluted one.
  • Question 10

Water samples

 

Sample Animals Found
A

stonefly larva, water snipe fly, alderfly, mayfly larva

B

rat-tailed maggot,  sludge worm, bloodworm

C

sludge worm, freshwater mussel, damselfly larva  

 

Here are the same samples again.

 

Suggest which water is from a fast-running stream.

CORRECT ANSWER
A
EDDIE SAYS
The final question in this activity - how did you get on? Sample A contains only species that live in clean water, plus the mayfly larvae that are semi-sensitive. This means it is probably a fast-running water source that is renewed regularly, which maintains its clean state. Are you getting to grips with this topic now? If you found some of these questions hard, why not reread the Introduction and then have another go?
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