PRACTICE EXAM QUESTIONS: IBB SYSTEMS AND MODELS
Which is an example of negative feedback?
A. An increase in air temperature increases the rate of melting of the Earth’s ice caps, thus decreasing the reflection of solar radiation.
B. An increase in a herbivore population, leading to overgrazing and thus to a decline in the herbivore population.
C. An increase in human birth rate compared with death rate leading to exponential increase in the human population.
D. A loss of vegetation leads to soil erosion and thus further loss of vegetation occurs.
(Total 1 mark)
Which row contains correct statements about exchanges between open and closed systems and their surroundings?
Open system / Closed systemA. / Exchanges matter but not energy / Exchanges neither matter nor energy
B. / Exchanges matter but not energy / Exchanges energy but not matter
C. / Exchanges energy but not matter / Exchanges neither matter nor energy
D. / Exchanges matter and energy / Exchanges energy but not matter
(Total 1 mark)
Over a long period of time, energy input to a system is
A. always equal to energy output.
B. usually greater than energy output.
C. always greater than energy output.
D. always less than energy output.
(Total 1 mark)
Which of the following can be considered an isolated system?
A. A rock in the bottom of the ocean
B. A small island
C. A spider on a tree
D. The entire cosmos
(Total 1 mark)
The diagram above is an example of
A. steady state equilibrium.
B. positive feedback.
C. negative feedback.
D. static equilibrium.
(Total 1 mark)
Which statement best describes the second law of thermodynamics?
A. In all ecosystems, energy is neither created nor destroyed, but it may be converted from one form to another.
B. Energy cannot leave a system.
C. The entropy of a system always remains constant for a spontaneous process.
D. In any isolated system entropy tends to increase spontaneously.
(Total 1 mark)
Which of the following descriptions best represents a closed system?
A. It exchanges energy but not matter.
B. It exchanges neither matter nor energy.
C. It exchanges matter but not energy.
D. It exchanges matter and energy.
(Total 1 mark)
Which of the following is the best definition of a system?
A. An assemblage of parts in which there are no changes over time
B. A set of biological components and their physical interactions
C. A set of components that function in an independent manner
D. An assemblage of parts, and their relationships, forming a whole
(Total 1 mark)
Which statement best illustrates the second law of thermodynamics?
A. When chemical energy such as food is converted into mechanical energy such as movement, much energy is lost as heat.
B. Total energy inputs to the biosphere are equal to total energy outputs.
C. Solar energy is converted into chemical energy in photosynthesis.
D. Energy is neither created nor destroyed, but it may be converted from one form to another.
(Total 1 mark)
Which row correctly gives examples of transfer and transformation processes?
Transfer / TransformationA. / Decomposition / Organic matter entering the ocean
B. / Evaporation / Decomposition
C. / Evaporation / Organic matter entering the ocean
D. / Organic matter entering the ocean / Evaporation
(Total 1 mark)
Of what is the diagram below an example?
A. Negative feedback
B. Positive feedback
C. Steady-state equilibrium
D. Static equilibrium
(Total 1 mark)
What does the first law of thermodynamics tell us?
A. Doing work always creates heat.
B. Entropy tends to increase.
C. Energy cannot be recycled.
D. All energy comes from other energy.
(Total 1 mark)
A desert with very low precipitation and little vegetation is an example of which type of system?
A. Open
B. Closed
C. Isolated
D. Closed and isolated
(Total 1 mark)
Below is a diagram of a food web. The letters represent different species of organism. S is a photosynthesizing organism.
What is organism U?
A. A producer
B. A primary consumer
C. A secondary consumer (carnivore)
D. An autotroph
(Total 1 mark)
Which of the following best describes the result of positive feedback in a system?
A. The system changing further in the same direction
B. The system remaining stable
C. The system changing in the opposite direction
D. The system remaining unchanged
(Total 1 mark)
Which statement is correct?
A. A lake is an example of an isolated system.
B. An open system exchanges energy but not matter with its surroundings.
C. The most common systems found on Earth are closed systems.
D. A closed system exchanges energy but not matter with its surroundings.
(Total 1 mark)
As a result of global warming, there could be increased
I. snowfall at the poles.
II. melting of polar ice caps.
III. photosynthesis.
Which could produce positive feedback in the Earth’s climate system?
A. I, II and III
B. I and III only
C. II only
D. III only
(Total 1 mark)
The diagram below shows the relative size of some energy flows between four types of organisms in a small pond, over one year.
What is the gross productivity of the primary consumers?
A. 2
B. 13
C. 15
D. 85
(Total 1 mark)
When a population exceeds the carrying capacity of the environment that supports it, which process often restores the equilibrium?
A. Succession
B. Negative feedback
C. Exponential growth
D. Positive feedback
(Total 1 mark)
(a) Define the term feedback.
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(1)
(b) Explain, with the help of an example, the term negative feedback in relation to an ecosystem.
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(Total 4 marks)
The diagram below represents the inputs and outputs of water from a lake over a period of time.
Assuming there is neither a rise nor a fall in the level of the lake, and there are no other inputs or outputs, what is the value of R?
A. P + I – E – S
B. I + P + E + S
C. (S + E) × (I + P)
D. I + P + E – S
(Total 1 mark)
What do outputs from an open system consist of?
A. Energy only
B. Matter only
C. Energy and matter
D. Neither energy nor matter
(Total 1 mark)
As disease spreads through a population, numbers fall. As the result of a reduction in contact between individuals, the rate of spread of the disease is reduced. This is followed by a recovery in numbers.
This is an example of
A. positive feedback
B. negative feedback
C. demographic transition
D. entropy
(Total 1 mark)
The diagram below represents the flows of energy through the biosphere.
Which of the following correctly shows the absorption or release of in each of the flows II and V?
Flow II / Flow VA. / Releases CO2 / Absorbs CO2
B. / Absorbs CO2 / Absorbs CO2
C. / Releases CO2 / Releases CO2
D. / Absorbs CO2 / Releases CO2
(Total 1 mark)
Which units would be most appropriate for flow II and the “chemical energy in plant biomass”?
Flow II / Chemical energy inplant biomass
A. / kJ m–2 yr–1 / kJ m–2
B. / kJ m–2 / kJ m–2 yr–1
C. / kg m–2 yr–1 / kg m–2
D. / kJ m–2 yr–1 / kg m–2 yr–1
(Total 1 mark)
Which of the following is an essential feature of a system in steady-state equilibrium?
A. Positive feedback mechanisms
B. Negative feedback mechanisms
C. Balanced inputs and outputs
D. High diversity
(Total 1 mark)
Inputs to a closed system may be
A. matter only.
B. energy only.
C. matter and energy.
D. heat only.
(Total 1 mark)
Which is an example of negative feedback?
A. Loss of vegetation leading to soil erosion leading to further loss of vegetation.
B. A decline in a large predator population after they have eaten most of their prey population.
C. Melting of permafrost in the tundra due to climatic change leading to further release of methane, causing further change.
D. Unsustainable slash and burn agriculture practices in tropical rain forests.
(Total 1 mark)
The Second Law of Thermodynamics states that in any
A. open system, entropy tends to increase spontaneously.
B. open system, entropy tends to decrease spontaneously.
C. isolated system, entropy tends to increase spontaneously.
D. isolated system, entropy tends to decrease spontaneously.
(Total 1 mark)
The diagram below shows storages (in percentage of total water) and flows in the global water cycle. The rates of flow are given in 1015 kg yr–1.
(a) (i) What is the source of energy which drives the water cycle? ......
(1)
(ii) In which of the processes given in the diagram does this energy enter the cycle?
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(b) (i) What percentage of all precipitation falls directly into the oceans?
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(ii) What percentage of all evaporated water comes from the oceans?
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(c) (i) Assuming the cycle is in steady state, what mass of water flows into the oceans through run-off and groundwater flow per year?
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(d) Name a storage of water in the biosphere that is not shown in the diagram, and explain how water is transferred in and out of this storage.
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(e) Identify each of the different processes referred to on the diagram as either transfer or transformation processes.
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