INVESTIGATING AN ECOSYSTEM: Quadrats
Estimate the abundance of each plant type in the three quadrats
shown and complete the table.
A
Dandelion
Plant Type
B
Buttercup
Quadrat A
C
Daisy
Quadrat B
Plantain
Quadrat C
Daisies
Buttercups
Plantain
Dandelions
Plant Survey
-Two Biology groups carried out a quadrat survey in a field to find out
the abundance and kinds of plants present.
- Group A took one quadrat sample
- Group B took 5 quadrat samples
Group A’s conclusion:
Group A
Plant Types Present
Dandelions
Plantain
Daisies
Buttercups
Grass
Abundance (1-25)
Quadrat 1
0
8
4
0
2
- There were only three plant
types present in the field.
- No plant type was particularly
dominant, with plantain being the
most common and grass being the
least common.
Group B
Plant Types
Present
Dandelions
Plantain
Daisies
Buttercups
Grass
Quadrat 1
4
0
10
2
25
Quadrat 2
10
2
9
5
20
Abundance
(1-25)
Quadrat 3
9
4
15
3
24
Quadrat 4
11
8
0
15
24
Quadrat 5
13
6
4
15
25
1. How many plant types did group B find in the field?
2. What plant type did group B find to be most abundant?
3. What plant type did group B find to be least abundant?
4. Which group do you think has obtained the most accurate information
about the kind and abundance of plants in the field?
5. Why did group A only record the presence of three plant types when
there are obviously more in the field?
6. After their quadrat survey, group B walked around the field and
identified eight different plant types. Explain why their survey only
indicated five different types.
7. How could group B have obtained even more accurate results still using
the quadrat method?
INVESTIGATING AN ECOSYSTEM: Pitfall Traps
-Two Biology groups carried out a pitfall trap survey in a woodland.
- Group A set one pitfall trap
- Group B set five pitfall traps
The results of both groups are shown:
Group A
Animals Present
Pitfall Trap 1
Rove Beetles
Ground Beetles
Wolf Spiders
Thrips
8
2
2
1
Group A’s Conclusion
- There were four different
kinds of small invertebrates
living in the woodland
- Rove beetles were most
common while thrips were the
least common.
Group B
Animal Types
Present
Rove Beetles
Ground Beetles
Wolf Spiders
Thrips
Centipedes
Snails
Ants
Number of Animal Types Present
Pitfall 1
2
0
6
2
1
1
2
Pitfall 2
1
0
8
1
0
0
4
Pitfall 3
2
3
10
2
0
0
6
Pitfall 4
1
1
8
3
1
0
1
Pitfall 5
6
2
8
0
2
0
1
1. How many kinds of small animal did group B find in the woodland?
2. What types of small animal did group B find to be most common?
3. What types of small animal did group B find to be least common?
4. Both groups saw wasps, bees and other similar insects in the wood.
Explain why these animals were not found in the pitfall trap.
5. Thrips provide food for beetles, spiders and centipedes. There were
hundreds roaming the forest floor. Explain why so few were in the traps?
6. Both groups were trying to obtain a specimen of a very rare beetle known
to live in the forest. Why did neither group obtain a specimen, and how could
they have improved their chances?
7. Which group do you think has obtained the most accurate information
about the amount and kind of small animals present on the woodland floor?
Explain why.
8. How could group B have obtained even more accurate information about the
amount and kind of small animal present still using pitfall traps?
Abiotic Factors: Light Intensity Survey
John and Laura compared the light intensity in two similarly sized areas of
waste ground. They took an area each and measured the light intensity at
different points.
How each pupil took their reading:
John (Area 1):
Laura (Area 2):
Time: 11 am
Time: 4 pm
Conditions: Bright sunshine
Conditions: Cloudy
Technique: Light meter held away
Technique: Light meter held close from
body and towards light
to body with back to light source
- John found the light intensity in Area 1 to be very high (H)
- Laura found the light intensity in Area 2 to be very low (A)
- The pupils concluded that Area 1 received more light than Area 2
1. Do you think the conclusion drawn by the two pupils is valid?
2. Give three reasons why the light intensity readings for area 2 will be lower
than they should be when compared to area 1.
3. Use you answer to describe the precautions that must be taken when
comparing two areas for light intensity.
WOODLAND TRANSECT SURVEY
Quadrat
Moisture
1
A
3
2
B
2
Grass
Daisies
Wood sorrel
6
0
20
8
0
15
Light Intensity
3
C
3
4
5
6
D
E
F
1
4
3
Abundance of Plant Type
8
10
15
20
0
0
5
11
15
10
10
5
7
8
G
H
2
3
(max 25)
23
25
16
19
0
0
9
H
4
10
H
3
25
22
0
25
22
0
Remember! Light intensity:
A (low) - H (high)
Moisture content: 1 (dry) – 8 (wet)
Examine the table of results for the transect study and answer the following
questions:
1. Describe what happens to light intensity as you move along the transect
from the woods into the field.
2. Is there a pattern to moisture values as you move into the field from the
woodland?
3. Describe what happens to the abundance of grass present on the ground as
you move along the transect from wood to field.
4. Describe what happens to the abundance of daisies present on the ground
as you move along the transect from wood to field.
5. Explain the probable reason for the change in the abundance of grass and
daises as you move out of the woods.
6. Describe what happens to the wood sorrel as you move out of the wood.
7. Give a possible reason for the change in the wood sorrel abundance.
8. Do you think the change in the moisture content of the soil can be used to
explain the observed differences in distribution of the plants as you move out
of the woodland? Give a reason for your answer.
Air Pollution Homework
The graph below shows the number of different species of crusty, leafy and shrubby lichens found in each
square kilometre around a city centre.
(a) How many species of leafy lichen are there 8km from the city centre? (1)
(b) What is the total number of lichen species 8km from the city centre? (1)
(c) Copy and complete the table below to show the number of each type of lichen and the total
number of lichen species as you move away from the city centre
(2)
(d) What happens to the total number of lichen species as you move further away from the city
centre? (1)
The level of sulphur dioxide in the air around the city was also measured and the results are shown in the
table below.
(e) On a piece of graph paper, plot units of sulphur dioxide against distance from city centre. On the
same graph plot the total number of lichen species against the distance from city centre.
ie.
(scales=1 ,each line=1 – total =3)
(f) Using information obtained from the graph, give a reason for the change in the total number of
different species of lichen as you move further away from the city centre. (1)
(g) Which type of lichen is least affected by sulphur dioxide? (1)
(h) If you found crusty, leafy and shrubby lichens what conclusion could you make about the level of
sulphur dioxide pollution in the air? (1)
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Bioaccumulation Homework
Look at the loch diagram below and answer the questions which follow.
(a) Construct a table to show the concentration of DDT found in the cells of each type of organism -arrange the information in increasing order of concentration. (2)
(b) By how many times did the concentration of DDT increase between loch water and plant plankton? (1)
(c) Between which two organisms did the pesticide concentration increase by exactly six times? (1)
(d) i. Which animal do you think was found to suffer most as a result of DDT poisoning? (1)
ii. Explain your answer (1)
(e) Suggest why the use of DDT has been banned in the UK (1)
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Energy in Ecosystems Homework
1.
Plants are always the ___________ organisms in food chains. They get their
energy from the ________. Arrows represent the _________ passing along the food
chain. At each link in the food chain some of the energy is lost by
_____________________________. A pyramid of _____________ shows the number
of organisms at each stage of the food chain. Sometimes the different __________ of
organisms causes the pyramid to be inverted.
(3)
2.
Draw a link between the words in the first column and the words in the second
column:
Tertiary consumer
Producer
Secondary consumer
Primary consumer
(3)
3.
Plant
Herbivore
Carnivore
a) What is a pyramid of biomass?
_______________________________________________________________(1)
b) Why is a pyramid of biomass sometimes more useful than a pyramid of numbers?
________________________________________________________________
________________________________________________________________(2)
4.
a) State two types of decomposer organisms: ____________ _____________(2)
b) What roles do decomposers play in the nitrogen cycle?
________________________________________________________________(1)
Keys Homework
2
River Pollution Homework
1. Methylene blue is a dye whose colour fades as it loses oxygen and therefore it can be used to
measure the oxygen level and level of bacteria in river water.
ie.
A biologist collected water samples from the sites shown in the diagram below. She carried out the “blue
dye” test on the samples she collected.
(a) Copy and complete the following table using the words;
Very Low
Low
High
Very High
(5)
(b) i. At which site would you expect to find the least number of plants and animals in the
river? (1)
ii. Explain why you would expect few organisms at this site. (1)
(c) What do you think is the likely source of the organic pollution in this river? (1)
(d) What evidence is there to suggest that the river recovers from the pollution? (2)
2. The graphs below show the oxygen concentrations upstream and downstream from the outflow
pipes of two different sewage works, A and B. The two sewage works receive equal quantities of
sewage and the two rivers are of equal size and speed.
(a) What is the oxygen concentration of the water upstream from sewage works A? (1)
(b) Calculate the percentage of oxygen lost from the water between the outflow of sewage works B
and point X (1)
(c) Complete the following sentence to describe the change in oxygen concentration which takes place
downstream from both sewage works;
As the distance downstream from the sewage works increases, the oxygen concentration
_____________ and then ______________
(1)
(d) Which sewage works is more efficient at removing waste material from the sewage ? Give a reason
for your answer. (2)
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