Name:_________________________________________________
IB1 Topic 1 & Topic 5.1, 5.2, 5.3
Summative Test
MULTIPLE ANSWER SHEET: Put a cross X in the answer box. If you make a mistake darken in the
box and put another X in the box you want.
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Name:
.
Topic 1 and 5.1, 5.2, and 5.3 Summative Exam
1. The graph below shows the correlation between the biomass of a marine worm, Arenicola, and the
percentage of organic nitrogen in the sand where it lives.
What statement can be made from the data?
A.
The increase in the biomass of the worm is due to an increase in the percentage of organic nitrogen.
B.
There is no relationship between the biomass of the worm and the percentage of organic nitrogen.
C.
The increase in the percentage of organic nitrogen is due to an increase in the biomass of the worm.
D.
As the biomass of the worm increases so does the percentage of organic nitrogen.
2. The levels of iron in liver tissue from 12 rats fed on beef and 11 rats fed on plant oils were compared
using the t-test to see if there was a significant difference at the 5% level.
Part of the table showing the critical values for the t-test is shown below.
Degrees of
freedom
p = 0.1
p = 0.05
p = 0.01
p = 0.001
19
1.729
2.093
2.861
3.883
20
1.725
2.086
2.845
3.850
21
1.721
2.080
2.831
3.819
22
1.717
2.074
2.819
3.792
23
1.714
2.069
2.807
3.767
What is the critical value above which the two samples can be considered significantly different?
A.
2.086
B.
2.080
C.
2.074
D.
2.069
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3.
What does the following scatter graph show?
A. No correlation between these variables
B. Strong positive correlation between these variables
C. Strong negative correlation between these variables
D. Weak negative correlation between these variables
4.
What does the size of the standard deviation indicate about data?
A. How accurately the data were measured
B. How widely the data are spread above and below the mean
C. Whether the mean is larger or smaller than it should be
D. Whether the reliability of the data is greater or less than 68%
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5. What do error bars on graphs show?
A. If the data is correct or not.
B. How variable the data is.
C. Which result is closest to the true result.
D. What statistical technique was used to eliminate incorrect results.
6. This question is about the food web below
What is the energy transfer level from the kangaroo rat to the weasel shown in the food web above?
A. Three times greater than the energy transfer from the roadrunner to the bobcat
B. Half the energy transfer from chaparral plants to the meadow mouse
C. A quarter of the energy transfer from the quail to the bobcat
D. Approximately the same as the energy transfer from the meadow mouse to the opossum
7. Why do food chains in an ecosystem rarely contain more than five organisms?
A. Nutrients are recycled by the decomposers back to the producers.
B. Nutrients are lost from the ecosystem when organisms die.
C. The conversion of food into growth by an organism is not very efficient.
D. Energy is recycled by the decomposers back to the producers.
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8. If humans become infected with the Ebola virus it can have devastating effects. Strong, but not certain,
evidence suggests that trading in animal products is the main reason for the spread of the Ebola virus to
humans. Which statement about the precautionary principle is correct?
A. In the absence of certainty about cause and effect, people should not be asked to stop trading in animal
products.
B. The burden of proof regarding a cause and effect relationship lies with scientists.
C. Because it is a probable cause, trading in animal products should be banned because of the potentially
devastating consequences.
D. The precautionary principle is not relevant in this case.
9. Which group of organisms in the carbon cycle converts carbon into a form that is available to primary
consumers?
A. Decomposers
B. Saprotrophs
C. Detritus feeders
D. Producers
10.Which of the following are greenhouse gases?
I. Oxides of nitrogen
II. Carbon dioxide
III. Methane
A. I and II only
B. I and III only
C. II and III only
D. I, II and III
11. What is a potential consequence of the rise in global temperatures on the Arctic ecosystem?
A.
Increased exposure to UV light
B.
Increased rate of decomposition of detritus
C.
Decreased success of pest species
D.
Increase in the ice habitat available to polar bears
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12. The graph below represents a sigmoid (S-shaped) population growth curve. Three sections of the curve
are indicated (1, 2 and 3).
In which of the sections is natality plus immigration greater than mortality plus emigration?
A.
1 only
B.
2 only
C.
1 and 2 only
D.
3 only
13. In the forest zone between Gabon and the Republic of Congo it is estimated that an epidemic of the
Zaire strain of the Ebola virus (ZEBOV) killed nearly 5000 gorillas, significantly reducing the population.
Which statement is supported by this information?
A.
Natality was greater than mortality.
B.
Mortality was equal to natality.
C.
Natality and immigration was greater than mortality and emigration.
D.
Mortality was greater than immigration and natality.
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14. Population size is influenced by certain factors.
If I = immigration, E = emigration, N = natality, M = mortality and (N + M) = (I + E) = 0, which phase is
this population in?
A. Exponential phase
B. Transitional phase
C. Plateau phase
D. Growth phase
15. (a) Define the terms species, population and community. (3 points)
Species:
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Population: .......................................................................................................................................................
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(b) Explain the shape of the pyramids of energy that are constructed by ecologists to represent energy flow
in an ecosystem. (3 points)
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16. The food web below shows some of the feeding relationships found between the organisms living in or
near a river in England.
(a) Identify an organism in the food web that is
(i) an autotroph.
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(ii)
both a secondary and tertiary consumer.
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(b)
Explain how the flow of energy in the food web differs from the movement of nutrients. (2)
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(c) Discuss reasons why the levels of a pyramid of energy differ in size. (2)
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17. (a)
Draw a labelled sigmoid population growth curve. (4)
18. Methane produced by anaerobic bacteria contributes substantially to atmospheric methane
concentration. These bacteria are found in a variety of habitats. Some live inside the cytoplasm of larger
unicellular organisms and are known as endosymbionts. In marine sediments, endosymbionts living in the
cytoplasm of a group of unicellular organisms, known as ciliates, can contribute up to 90% of methane
production.
To see if endosymbionts in freshwater sediments had the same effect on methane production a one-year
study was carried out in Holland. The graph below shows the rate of methane production by untreated
sediment samples and sediment samples treated to kill the ciliates containing endosymbionts. The standard
deviations are indicated by bars. The total number of ciliates is also indicated by circles.
150
3
100
2
50
1
0
O
N
D
J
F
M
A
Time / months
M
J
J
A
S
Rate of methane production /
mol methane g–1 h–1
Ciliate numbers / ml sediment
key:
untreated
treated
0
(a) State what the standard deviation indicates. (1)
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(b) State the maximum number of ciliates and the month in which the maximum occurs. (1)
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(c) Compare the methane production in the untreated and treated samples. (2)
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(d) Deduce, with reasons, whether the endosymbionts in the ciliates are responsible for the methane
produced by the sediment samples. (2)
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(e) Explain how methane and other greenhouse gases cause global warming. (2)
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Models predict global warming will cause sea temperatures to rise by approximately 2C by 2100. An
investigation was carried out to study the effect of slight increases in temperature on the ability of Antarctic
marine molluscs to carry out basic activities essential for survival.
The graph below shows the effect of temperature on the percentage of limpets (Nacella concinna) able to
right themselves after being turned over.
100
% righting in 24hrs
80
60
40
20
0
0
1
2
3
4
Temperature / ºC
5
6
(f) Outline what the two parts of the scientific name Nacella concinna refer to. (1)
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(g) State the relationship between temperature and the percentage righting in N. concinna. (1)
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(h) Estimate the percentage change of N. concinna able to right themselves when the temperature is raised
from 0C to 2.5C. (1)
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(i) At present, the maximum summer temperature in the normal Antarctic environment of this organism is
1C. Suggest what might be the effect on the survival of this organism if the predicted rise in sea temperature
due to global warming occurs. (2)
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