Question 1

Which of the following statements about termites is true?

Accepted Answer

A)  Termites are an exclusively wood-eating family. 
B)  Termites can digest cellulose directly. 
C)  Termites maintain a high biomass in dry environments. 
D)  Termites build mounds that are low in nutrients but high in organic carbon. 
E)  Termites recycle about 80% of the ecosystem's carbon. 
A)  Termites are an exclusively wood-eating family. 
B)  Termites can digest cellulose directly. 
C)  Termites maintain a high biomass in dry environments. 
D)  Termites build mounds that are low in nutrients but high in organic carbon. 
E)  Termites recycle about 80% of the ecosystem's carbon.

Question 2

In the global carbon cycle, the smallest pool of carbon is found in

Accepted Answer

A)  rocks. 
B)  the atmosphere. 
C)  fossils fuels. 
D)  marine organic matter. 
E)  the oceans. 
A)  rocks. 
B)  the atmosphere. 
C)  fossils fuels. 
D)  marine organic matter. 
E)  the oceans.

Question 3

In an ecosystem consisting of phytoplankton being grazed by zooplankton, you would expect to find

Accepted Answer

A)  a higher biomass of consumers than producers. 
B)  a large biomass of producers but fewer consumers. 
C)  no consumers. 
D)  an equilibrium between the producers and consumers. 
E)  no producers. 
A)  a higher biomass of consumers than producers. 
B)  a large biomass of producers but fewer consumers. 
C)  no consumers. 
D)  an equilibrium between the producers and consumers. 
E)  no producers.

Question 4

A farmer has a large field that she uses to grow wheat with minimal agricultural inputs. The wheat grown in this field originally gave a reasonable yield but over time the yield has steadily declined until it becomes economically unviable. Frustrated, the farmer abandons growing wheat in the field and the following year instead plants lentils and produces a good harvest. The farmer grows lentils again the following year and produces another good yield, but the following year she in unable to source lentil seed stock in time to sow the field. Rather than leave the field fallow, she decides to cut her losses and sow wheat again. To her surprise, despite identical climatic conditions and uniform disease conditions, the wheat harvest noticeably improved. What could explain this observation?

Accepted Answer

A)  Thunderstorms have converted atmospheric nitrogen into oxides which have been deposited in the soil by rain and accumulated. 
B)  Lentils secrete an exotoxin which has killed soil bacteria, resulting in less competition for nutrition. 
C)  Wheat stubble had built up in the soil of the field, inhibiting the growth and development of future wheat plants. Two years of lentils gave enough time for decomposing microorganisms to break down the build-up of stubble. 
D)  Lentils are a leguminous plant, therefore they have increased the available nitrogen levels in the field. 
E)  Lentils use fewer nutrients than wheat, meaning there was more available for the wheat when it was grown after two years of growing lentils. 
A)  Thunderstorms have converted atmospheric nitrogen into oxides which have been deposited in the soil by rain and accumulated. 
B)  Lentils secrete an exotoxin which has killed soil bacteria, resulting in less competition for nutrition. 
C)  Wheat stubble had built up in the soil of the field, inhibiting the growth and development of future wheat plants. Two years of lentils gave enough time for decomposing microorganisms to break down the build-up of stubble. 
D)  Lentils are a leguminous plant, therefore they have increased the available nitrogen levels in the field. 
E)  Lentils use fewer nutrients than wheat, meaning there was more available for the wheat when it was grown after two years of growing lentils.

Question 5

Food chains are usually short. Reasons for this are thought to be

Accepted Answer

A)  the energy available at each level. 
B)  populations of organisms in a food web are in stable equilibrium, which is maintained by short chains. 
C)  there is a hierarchy in which species fed on those below and are eaten by those in levels above it, and so is limited by the tropic levels. 
D)  the relatively few organisms in any ecosystem. 
E)  Generally the reasons are unknown. 
A)  the energy available at each level. 
B)  populations of organisms in a food web are in stable equilibrium, which is maintained by short chains. 
C)  there is a hierarchy in which species fed on those below and are eaten by those in levels above it, and so is limited by the tropic levels. 
D)  the relatively few organisms in any ecosystem. 
E)  Generally the reasons are unknown.

Question 6

All of the following have a significant gaseous atmospheric pool EXCEPT

Accepted Answer

A)  carbon. 
B)  nitrogen. 
C)  oxygen. 
D)  phosphorus. 
E)  All of the answers have a significant atmospheric pool. 
A)  carbon. 
B)  nitrogen. 
C)  oxygen. 
D)  phosphorus. 
E)  All of the answers have a significant atmospheric pool.

Question 7

All of the following processes add nitrogen to ecosystems EXCEPT

Accepted Answer

A)  oxidation of nitrogen by lightning. 
B)  fixation by symbiotic bacteria. 
C)  volatilisation of organic wastes. 
D)  industrial high temperature conversion of atmospheric nitrogen. 
E)  fixation by cyanobacteria. 
A)  oxidation of nitrogen by lightning. 
B)  fixation by symbiotic bacteria. 
C)  volatilisation of organic wastes. 
D)  industrial high temperature conversion of atmospheric nitrogen. 
E)  fixation by cyanobacteria.

Question 8

A photosynthetically active plant in moist soil and full sun is respiring rapidly. What would be the NET carbon cycle status of this plant at this point in time?

Accepted Answer

A)  It is a net exporter of carbon, returning large amounts of carbon to the atmosphere via respiration. 
B)  There is no net gain or loss of carbon; the plant both accumulates and returns carbon to the carbon cycle at roughly equal rates. 
C)  It is a net accumulator of carbon, converting atmospheric carbon primarily into ATP, NADPH and FADH2. 
D)  It is a net exporter of carbon, returning large amounts of carbon to the atmosphere via the decomposition of dead and decaying plant matter. 
E)  It is a net accumulator of carbon, converting atmospheric carbon primarily into carbohydrates. 
A)  It is a net exporter of carbon, returning large amounts of carbon to the atmosphere via respiration. 
B)  There is no net gain or loss of carbon; the plant both accumulates and returns carbon to the carbon cycle at roughly equal rates. 
C)  It is a net accumulator of carbon, converting atmospheric carbon primarily into ATP, NADPH and FADH2. 
D)  It is a net exporter of carbon, returning large amounts of carbon to the atmosphere via the decomposition of dead and decaying plant matter. 
E)  It is a net accumulator of carbon, converting atmospheric carbon primarily into carbohydrates.

Question 9

Termites play a crucial role as decomposer organisms in dry soils. Termites have which of the following advantages in arid regions?

Accepted Answer

A)  Insulating properties of their nests 
B)  Co-operative social structure 
C)  Ability to store food for long periods 
D)  Concentrate moist nutrients in their nests 
E)  All of these answers contribute to the success of termites in arid regions. 
A)  Insulating properties of their nests 
B)  Co-operative social structure 
C)  Ability to store food for long periods 
D)  Concentrate moist nutrients in their nests 
E)  All of these answers contribute to the success of termites in arid regions.

Question 10

Compared to a similar but undisturbed reef, a coral reef recovering after severe storm damage would generally have

Accepted Answer

A)  higher productivity and lower biomass. 
B)  lower productivity and lower biomass 
C)  higher productivity and higher biomass 
D)  lower productivity and lower biomass. 
E)  about the same productivity but lower biomass. 
A)  higher productivity and lower biomass. 
B)  lower productivity and lower biomass 
C)  higher productivity and higher biomass 
D)  lower productivity and lower biomass. 
E)  about the same productivity but lower biomass.

Question 11

According the first law of thermodynamics, energy is conserved. That is, the internal energy of a system changes as energy flows in or out of it. In biological terms, this can be interpreted as meaning that whenever energy is transformed from one form to another, some is lost (typically as thermal energy). What does this tell us in relation to the structure of an ecological pyramid?

Accepted Answer

A)  Whenever an organism eats another, not all of the energy consumed is converted into usable energy. 
B)  There will always be fewer top predators than those that are consumed at the base. 
C)  The number of mid-range organisms in a pyramid will be fewer than those at the top. 
D)  All of the options listed are correct. 
E)  The number of mid-range organisms in a pyramid will be more than those at the bottom. 
A)  Whenever an organism eats another, not all of the energy consumed is converted into usable energy. 
B)  There will always be fewer top predators than those that are consumed at the base. 
C)  The number of mid-range organisms in a pyramid will be fewer than those at the top. 
D)  All of the options listed are correct. 
E)  The number of mid-range organisms in a pyramid will be more than those at the bottom.

Question 12

Which of the following ecosystems would you expect to have the highest primary productivity?

Accepted Answer

A)  A savanna grassland 
B)  A coral reef 
C)  A tropical rainforest 
D)  A deciduous forest 
E)  Oceans 
A)  A savanna grassland 
B)  A coral reef 
C)  A tropical rainforest 
D)  A deciduous forest 
E)  Oceans

Question 13

Which of the following statements is NOT correct?

Accepted Answer

A)  97 per cent of the world's water is in the oceans. 
B)  Some of the world's water is in inaccessible storage pools. 
C)  Transpiration removes water from circulation. 
D)  Soil moisture and ground water provide substantial pools of water. 
E)  Water circulates in the atmosphere by convection. 
A)  97 per cent of the world's water is in the oceans. 
B)  Some of the world's water is in inaccessible storage pools. 
C)  Transpiration removes water from circulation. 
D)  Soil moisture and ground water provide substantial pools of water. 
E)  Water circulates in the atmosphere by convection.

Question 14

Plant growth is found to be particularly vigorous in a rural area of Australia, until the opening of a bauxite mine for Al production. After the opening of the mine, the growth rate of plants declines in a manner proportional to the plants' proximity to the mine. Rainfall is good, the soil is neutral and there is no change in pathogen levels or soil nutrient content. Why might plant growth be limited around the mine?

Accepted Answer

A)  The mine is leeching nutrients from the surrounding soil via its tailings dam. 
B)  Mine construction has disturbed a reservoir of previously bound toxins in the soil. 
C)  The activities of the mine have increased Al3+ levels in the soil, which is toxic to root growth and development. 
D)  Dust and run-off from the mine has increased the Al content of surrounding soils. The Al has bound to phosphorous causing it to become immobile and unavailable to plants. 
E)  Dust and run-off from the mine has increased the Al content of surrounding soils. The Al has bound to nitrogen causing it to become immobile and unavailable to plants. 
A)  The mine is leeching nutrients from the surrounding soil via its tailings dam. 
B)  Mine construction has disturbed a reservoir of previously bound toxins in the soil. 
C)  The activities of the mine have increased Al3+ levels in the soil, which is toxic to root growth and development. 
D)  Dust and run-off from the mine has increased the Al content of surrounding soils. The Al has bound to phosphorous causing it to become immobile and unavailable to plants. 
E)  Dust and run-off from the mine has increased the Al content of surrounding soils. The Al has bound to nitrogen causing it to become immobile and unavailable to plants.

Question 15

The world's major oceanic fisheries are in upwelling zones because

Accepted Answer

A)  this is where the warmest and thus most productive waters are found. 
B)  deep water is forced up in these zones bringing fish to depths where they are more economically fished. 
C)  deep water is forced up in these zones bringing nutrients to phytoplankton near the surface. 
D)  the deep water forced up in these zones contains high levels of phosphorous. 
E)  deep water is forced up in these zones bringing phytoplankton to fish near the surface. 
A)  this is where the warmest and thus most productive waters are found. 
B)  deep water is forced up in these zones bringing fish to depths where they are more economically fished. 
C)  deep water is forced up in these zones bringing nutrients to phytoplankton near the surface. 
D)  the deep water forced up in these zones contains high levels of phosphorous. 
E)  deep water is forced up in these zones bringing phytoplankton to fish near the surface.

Question 16

In an ecosystem, the total amount of living material present at a given time

Accepted Answer

A)  is a measure of the community structure of the system. 
B)  is a measure of primary productivity. 
C)  is the biomass of the system. 
D)  is a measure of the rate of turnover of organisms. 
E)  contributes to the base of the ecological pyramid. 
A)  is a measure of the community structure of the system. 
B)  is a measure of primary productivity. 
C)  is the biomass of the system. 
D)  is a measure of the rate of turnover of organisms. 
E)  contributes to the base of the ecological pyramid.

Question 17

Experiments using 'potted webs' showed that the number of trophic levels in a food chain was limited by the

Accepted Answer

A)  amount of energy at the bottom of the chain only if energy levels were kept far below natural levels. 
B)  amount of energy at the top of the chain in all cases. 
C)  amount of energy at the bottom of the chain in all cases. 
D)  size of the experimental pot. 
E)  amount of energy at the bottom is dependent on the number of relationships in which any species is involved. 
A)  amount of energy at the bottom of the chain only if energy levels were kept far below natural levels. 
B)  amount of energy at the top of the chain in all cases. 
C)  amount of energy at the bottom of the chain in all cases. 
D)  size of the experimental pot. 
E)  amount of energy at the bottom is dependent on the number of relationships in which any species is involved.

Question 18

A major difference between energy cycles and the cycling of inorganic materials through ecosystems is that

Accepted Answer

A)  energy is continuously added to the cycle while materials are drawn from geologic stores. 
B)  energy cycling occurs on a global scale while materials are cycled on a local scale. 
C)  energy cycles are short while material cycles are long. 
D)  energy cycling is global while inorganic materials change with the location. 
E)  All of the answers are true. 
A)  energy is continuously added to the cycle while materials are drawn from geologic stores. 
B)  energy cycling occurs on a global scale while materials are cycled on a local scale. 
C)  energy cycles are short while material cycles are long. 
D)  energy cycling is global while inorganic materials change with the location. 
E)  All of the answers are true.

Question 19

Compared to most of the world, Australia has

Accepted Answer

A)  areas of very high rainfall. 
B)  extremely variable rainfall. 
C)  a majority of ecosystems limited by water. 
D)  a large proportion of dry area. 
E)  All of the answers are true. 
A)  areas of very high rainfall. 
B)  extremely variable rainfall. 
C)  a majority of ecosystems limited by water. 
D)  a large proportion of dry area. 
E)  All of the answers are true.

Question 20

Most of the world's carbon stores are in

Accepted Answer

A)  the enormous biomass of the world's tropical rain forests. 
B)  krill populations in the cold oceans of the world. 
C)  rocks. 
D)  trees. 
E)  fossil fuels. 
A)  the enormous biomass of the world's tropical rain forests. 
B)  krill populations in the cold oceans of the world. 
C)  rocks. 
D)  trees. 
E)  fossil fuels.

Exam 45: Ecosystems

Which of the following statements about termites is true?

In the global carbon cycle, the smallest pool of carbon is found in

In an ecosystem consisting of phytoplankton being grazed by zooplankton, you would expect to find

Food chains are usually short. Reasons for this are thought to be

All of the following have a significant gaseous atmospheric pool EXCEPT

All of the following processes add nitrogen to ecosystems EXCEPT

A photosynthetically active plant in moist soil and full sun is respiring rapidly. What would be the NET carbon cycle status of this plant at this point in time?

Termites play a crucial role as decomposer organisms in dry soils. Termites have which of the following advantages in arid regions?

Compared to a similar but undisturbed reef, a coral reef recovering after severe storm damage would generally have

Which of the following ecosystems would you expect to have the highest primary productivity?

Which of the following statements is NOT correct?

The world's major oceanic fisheries are in upwelling zones because

In an ecosystem, the total amount of living material present at a given time

Experiments using 'potted webs' showed that the number of trophic levels in a food chain was limited by the

A major difference between energy cycles and the cycling of inorganic materials through ecosystems is that

Compared to most of the world, Australia has

Most of the world's carbon stores are in

Nature of Molecules

Biomolecules

The Chemistry of Life

Functioning Cells

Movement Across Membranes

Harvesting Energy

Cells, Tissues and Signals

Cell Division

Inheritance

Genes, Chromosomes and Dna

The Genetic Code

Gene Expression

Genomes, Mutation and Cancer

Viruses

Genetic Engineering and Biotechnology

Reproduction, Growth and Development of Flowering Plants

Structure of Plants

Plant Nutrition, Transport and Adaptation to Stress

Plant Hormones and Growth Responses

Animal Reproduction

Animal Development

Homeostasis: Water, Solutes and Excretion

Gas Exchange in Animals

Circulation

Metabolism, Temperature Regulation and Environmental Stress

Animal and Human Nutrition

Innate Defences and the Immune System

Hormonal Control in Animals

Nervous Systems

Animal Movement

Animal Behaviour

Evolving Life

Evolving Earth

Mechanisms of Evolution

Bacteria

The Protists

Plants

Fungi

Simple Animals: Sponges to Flatworms

Annelids, Molluscs, Nematodes and Arthropods

Echinoderms and Chordates

Australian Biota

Population Ecology

Living in Communities

Human Impacts

Filters