Science Quest 10
Chapter 7: Global systems
Answers (Teacher version)
Think about global systems
Which organism is being
blamed for causing the sixth
mass extinction?
Humans are being blamed for causing the sixth mass extinction.
What has both a ‘layer’ and a
‘zone’ in it?
Ozone has both a ‘layer’ and a ‘zone’ in it.
When is the ‘laughing gas’
nitrous oxide nothing to laugh
about?
It is a serious matter when nitrous oxide becomes a pollutant and
contributes to the enhanced greenhouse effect and global
warming.
If global cooling did increase
the size of the human brain,
what effects might global
warming have?
Possibly the reverse will be happen — the brain will reduce in
size. However, scientists suggest that because we have
technology and culture, this will act as a buffer against hot
climates
Are humans still evolving?
Yes, two genes involved in regulating brain size have been
subject to recent natural selection.
Are you a climate-change
sceptic?
Global warming is a hot topic. Some theories suggest that
humans are not to blame for this phenomenon and that the
increased temperatures being experienced are merely a part of a
natural cycle. The majority of theories point to human actions as
causes of global warming.
Understanding and inquiring
7.1
Revisiting cycles and spheres
1.
Biosphere
2
Atmosphere, lithosphere, hydrosphere, biota
3.
They are all components of the biosphere that interact together to create the life support
system that is the biosphere.
4.
The term ‘biota’ refers to living things that consist of and include organic compounds
5.
Answers will vary.
6.
Stratosphere
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7.
The ozone layer is important because it blocks out harmful UV rays, reducing the amount
of damaging radiation reaching the Earth’s surface.
8.
Oxygen, methane, carbon dioxide and ozone
9.
CFCs react to form chlorine atoms, which destroy ozone, increasing the amount of UV
rays reaching Earth and harming living organisms.
10.
Water cycle
11.
Rain, hail, snow and sleet
12.
The Earth’s crust and soils
13.
Dominant vegetation type
14.
Lithosphere
15.
Responses will vary. May include: latitude, temperature and rainfall
16.
Photosynthesis takes up carbon in the form of carbon dioxide. Cellular respiration gives
off carbon dioxide as a waste product, as does the burning of fossil fuels. All of which
contribute carbon to the carbon cycle.
17.
Nitrogen-fixing bacteria take nitrogen from the air and convert it to ammonia; nitrifying
bacteria take nitrites and convert them to nitrates, which are used by plants; denitrifying
bacteria take nitrates and convert them back into nitrogen gas in the air.
18.
Answers will vary.
19.
(a)
Atmospheric carbon dioxide
(b)
Nitrogen gas in the atmosphere and nitrates in the soil of the lithosphere
(c)
Phosphorus in the protein of the biota
(d)
Water and hydrosphere
(a)
CFCs destroying the ozone layer
(b)
Erosion of soils and overuse of soil for agriculture
(c)
Toxic and industrial waste and untreated sewage
(d)
Continued burning of fossil fuels, deforestation, industrialisation
(e)
Excessive use of fertilisers containing phosphorus and nitrogen.
20.
21.
DNA is made up of nucleic acids, a component of which is the atom phosphorus.
22.
Student eBookPLUS
23.
See pages 221–3 of the textbook.
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7.2
Patterns, order and organisation: Climate patterns
1.
Amount of energy from the sun reaching the surface; the differing abilities of land and
water to absorb and emit radiant heat; the tilt of the Earth’s axis; and the features of the
land
2.
The difference in surface temperature between the poles and the tropics
3.
Amount of friction caused by land surface; ocean currents; local variations in air pressure
and temperature; variations in water and land temperature; and altitude
4.
Warm surface water near the equator sinks and cools as it moves towards the poles, while
the cold water in polar regions rises and warms as it moves towards the equator.
5.
The Gulf Stream carries warm water from the equator.
6.
Sandy soils reflect more energy from the sun than dark, fertile soils because their lighter
colour absorbs less energy.
7.
Explanations include: Changing land masses, currents, landforms and the amount of
vegetation.
8.
Answers will vary. Some suggestions are:
(a)
Change of habitat and climate, creating competition for space and resources,
which may affect others that are unable to migrate.
(b)
Heat stress and reaching of tolerance limits of living organisms, which could
affect organism’s ability to reproduce
9.
Responses will vary.
10.
Responses will vary.
7.3
Global warming
1.
This is because the atmosphere consists of a blanket of gases that trap heat to keep the
temperature of Earth stable.
2
(a)
The trapping of radiant heat from the Earth by the atmospheric gases
(b)
Increase in the amount of greenhouse gases in the atmosphere that are trapping
heat, causing the atmosphere to heat up.
(c)
3.
The rising temperature of the Earth
Melting of icecaps; rising sea levels; increased coastal flooding; unusual weather patterns
and ocean currents; consequent threats to the survival of some living things
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4.
Carbon dioxide: cellular respiration, decomposition, deforestation, burning fossil fuels
Methane: livestock, bacteria in bogs, rice paddies
CFCs: aerosols, refrigerants, plastic foam production, dry cleaning
5.
Answers will vary; however, they should mention consistent presence of carbon dioxide
as a contributor in all processes. Refer to page 229 of the textbook.
6.
Ozone absorbs much of the sun’s UV radiation, ensuring just the right amount for life
gets through to Earth’s surface. If there is not enough ozone, this radiation is detrimental
to all living organisms.
7.
The use of ice cores provides detailed information about the level of carbon dioxide in
the atmosphere over time. Dust, gases and other atmospheric substances become trapped
in layers of snow. The build-up of snow and ice over time gives a timeline of carbon
dioxide concentration.
8.
Carbon dioxide and methane are both contributors to the greenhouse effect and are
locked in permafrost. If permafrost thaws due to global warming, these gases will be
released into the atmosphere, increasing the rate of climate change.
9.
To reduce the rate of climate change, humans can reduce their reliance on fossil fuels by
using greener and more efficient forms of energy; reduce, reuse and recycle; reduce the
number of grazing animals used for agriculture; reduce fertiliser use.
10. to 21. Responses will vary.
22.
eBookPLUS activity
7.4
Heating up for Thermageddon?
1.
Every living thing is dependent on the characteristics of their habitat.
2.
37 °C
3.
A human will die.
4.
Answers will vary. Suggestions include: stay inside during the day, sleep during the
hottest part of the day, air conditioning, shower or bathe regularly, reduce clothing worn.
5.
It means how much temperature will increase depending on the increase of carbon
dioxide in the atmosphere.
6.
(a)
Humans: heat stress, death, migration, evolution of the body to cope with heat
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(b)
Ocean life: extinction of certain species, separate life from food sources, affect
plankton populations and the entire ocean food chain, reduction of oxygen,
destruction of habitats
(c)
Biodiversity: reduction in biodiversity due to intolerance to heat and inability to
adapt; extinction; permanent migration of animals to cooler climates; loss of
habitats and ecosystems.
7. to 14. Responses will vary.
7.5
Some cool solutions
1.
There are too many variables that influence climate for computer modelling to provide
completely accurate predictions.
2.
Evidence suggests that increase in greenhouse gases over the last 100 years has had an
impact and can be reduced with certain measures.
3.
Reduction of fossil fuel use, increased use of alternative energy sources, a change in
consumption of food, recycling of products.
4.
Geosequestration is the separation of carbon dioxide from flue gases, compression and
piping it to a suitable site underground. This process can take excess carbon dioxide from
the atmosphere, reducing its effect on climate change and global warming.
5.
Wooden products act as a carbon sink — 82% of carbon originally in the sawn timber
remains stored in the wood. Manufacturing with these products reduces the amount of
carbon released into the atmosphere and contributing on global warming.
6.
Rate of biodiversity loss; climate change; nitrogen and phosphorus cycles; stratospheric
ozone depletion; atmospheric aerosol loading; chemical pollution; ocean acidification;
fresh water use; change in land use
7.
Metagenomics is a technology that combines DNA sequencing with molecular and
computational biology. It is being used to research the difference between the bacteria in
wallabies’ guts the bacteria in cows’ guts and to show how wallabies produce less
methane as a result.
8.
Methane is a major contributor to global warming. Wallabies are herbivores like
livestock but do not produce as much methane. CSIRO scientists are researching how
they can apply the action of the wallaby bacteria to the farming of livestock.
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9.
The Kyoto Protocol is a document devised to reduce the amount of greenhouse gases
produced by industrialised countries. It signifies the ongoing cooperation between most
of the world’s nations to reduce carbon dioxide and other greenhouse gas emissions and
slow down global warming.
10.
Responses will vary.
11.
eBookPLUS activity
7.6
Global warming — believe it or not?
1. to 11. Responses will vary.
7.7
Ozone alert!
1.
Atmosphere
2.
It blocks out 95% of harmful UV radiation.
3
(a)
CFCs
(b)
Answers will vary. Refer to page 243 of the textbook for guidance.
4.
There has been a reduction in and, in some cases a complete ban of, the use of CFCs
through the introduction of the ‘Montreal Protocol’.
5.
(a)
Total Ozone Mapping Spectrometer
(b)
Satellite-based observations
(c)
Measure of total ozone
(d)
Responses will vary.
6.
Answers will vary — group activity
7.
(a)
As the size of the hole in the ozone layer increases, the amount of ozone measured
in Dobson units decreases, as does the temperature in the stratosphere.
(b)
Ozone traps the UV radiation from the sun and, therefore, increasing the
temperature of the stratosphere. If the concentration of ozone decreases due to an
increasing hole in this layer, not as much UV radiation is trapped and, therefore, a
decrease in temperature is experienced.
8.
(c)
Atmosphere
(a)
Our ozone layer blocks out more than 95 per cent of the ultraviolet rays entering
the atmosphere. Any decrease in the amount of ozone in the ozone layer increases
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the percentage of UV that reaches the Earth’s surface. These additional UV rays
cause damage to all living things, as they are adapted to being protected from
ultraviolet radiation by the ozone layer.
(b)
Propellant in aerosol spray cans, coolant in refrigerators and air conditioners
(c)
In the stratosphere, bonds in CFC molecules are broken and free chlorine atoms
are released. These chlorine atoms are involved in reactions that destroy ozone.
The chlorine atoms are then released back into the atmosphere where they
continue to be involved in ozone destruction.
(d)
An increase in sunlight means an increase in UV, which converts chlorine
molecules into free chlorine atoms, which destroy ozone. Temperature changes
affect cloud formation, which in turn affects the formation of free chlorine atoms.
9.
Responses will vary.
10.
Responses will vary.
7.8
Biodiversity and climate change
1.
Oxygen came from the first organisms to photosynthesise.
2.
For organisms to be better suited, there must first be variation or biodiversity.
3.
(a)
Total variety of living things on Earth, their genes and the ecosystems in which
they live
(b)
Variation within the genes of a species.
(c)
Diversity in populations of organisms
(d)
Diversity in ecosystems
4.
Genetic, species and ecological
5.
Genetic variation is important as it increases the chance that at least one of the variations
may enable some of the population to survive to reproduce the next generation
6.
DNA
7.
Genes act as code for the phenotypes or characteristics of organisms.
8.
Responses will vary. Generally, students should be able to show that DNA is the basis for
genes, and that genes code for certain proteins that contribute to the traits organisms
have.
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9.
(a)
Individuals within a species share the same genes that code for a particular
feature; alleles are the alternative forms of genes that give rise to variation.
(b)
Genotype is the combination of alleles for a particular trait or phenotype.
(c)
Genotype is the combination of alleles for a particular trait; the combination of all
alleles within a group is called a gene pool.
(d)
Survival is the existence of an organism within its habitat where it relies on
diversity to increase its chances of living and adapting; extinction is the complete
disappearance of the entire population of a particular organism.
10.
Low diversity decreases the chances for an organism or population to adapt and survive
change; high diversity increases these chances.
11.
Limited diversity within a population makes it vulnerable and unable to adapt change.
This can result in the population number decreasing significantly in the event of a natural
disaster or great change.
12.
High diversity increases the amount of resources available to organisms living within
ecosystems and, therefore, increases the survival chances.
13.
Temperature and annual rainfall
14.
Tolerance range refers to the physiological limits in which an organism functions at an
optimal level; for example, temperature.
15.
Global warming has seen the increase in Earth’s temperature and decrease in annual
rainfall within certain periods of time.
16.
If the species is unable to migrate or adapt to the new conditions, they would be at risk of
extinction.
17.
Changes in species ranges and migration patterns, shifts in genetic composition of some
species that have a short life cycle and changes in lifestyle and reproduction rates
18.
Climate change is causing the flowering times of some plants to be out of synchronisation
with their pollinators, which results in less plants being pollinated and fewer bearing fruit
containing seeds to produce the next generation.
19.
Terrestrial biodiversity; primary industries; water resources and freshwater biodiversity;
marine biodiversity and resources; human health; cities and infrastructure; emergency
management; and social and economic issues
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20.
The two phases are humans spreading throughout the world and humans using
agriculture.
21. to 31. Responses will vary.
7.9
Biosphere 2
1.
This is because the Earth is known as biosphere 1.
2.
A desert, a salt marsh, a tropical savanna, an ocean and a rainforest
3.
It was designed as an eco-technological model for space exploration and colonisation.
4.
It is a closed system.
5.
Increased level of respiration, which requires oxygen and generates carbon dioxide.
Humans would use and create gases at a quicker rate than they could be taken up and
converted by plants.
6.
Oxygen concentrations had dropped to 14%, which is barely enough to keep humans
alive and functioning.
7.
Oxygen was being consumed by microbes in the excessively rich food crop soil, which
then also increased carbon dioxide levels
8.
If this sink had not been available, the air would have become unbreathable much earlier.
9.
They decreased available light necessary for photosynthesis.
10.
It was cycled by condensation, artificial rain, evaporation, transpiration and sub-soil
drainage.
11.
The experiences and findings can provide scientists with a greater understanding and
ability to predict Earth’s futures if carbon dioxide levels continue to increase.
12. to 18. Responses will vary.
7.10
SWOT analyses and fishbone diagrams
1. to 5. Responses will vary.
Looking back
1.
(a)
The most accepted view is that global warming is caused by industrialisation and
the increased use of fossil fuels, which increases the amount of greenhouse gases
in the atmosphere, causing the Earth’s temperature to rise.
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(b)
Some examples are climate change, decrease in biodiversity, hole in the ozone
layer, increased global temperatures and extinction of species.
(c)
Responses will vary.
(d)
Responses will vary.
(e)
Opinion is a personal view; theory is an educated and researched collation of
thoughts; a fact is a proven idea.
(f)
Responses will vary.
(g)
Responses will vary.
(h)
Data can be viewed differently by scientists; some see climate change as being a
cyclic and natural occurrence, not all believe that humans are the cause of climate
change.
2.
Responses will vary.
3.
Responses will vary.
4.
Biodiversity refers to the variety of all living things on Earth. Without biodiversity,
organisms reduce their chance of surviving change caused by natural disasters or human
induced events.
5
(a)
The restricted habitat limits the possum’s ability to find a suitable nesting site and
preferable mate, causing reproductive isolation.
(b)
Abiotic factors would be temperature, wind, rainfall and snowfall. Biotic factors
would be food resources, suitable mates and niches.
(c)
Responses will vary.
(d)
Extinction means the total destruction of a species whereby they are no longer
able to reproduce to populate an area or be found in the natural environment.
(e)
Certain plants may be reduced due to decreased pollination; prey species that feed
upon the possum will be affected, which will then further affect the food chain
and web the possum is a part of.
6.
Refer to page 223 of the textbook.
7.
(a)
Rising sea levels and, therefore, salinity are the result of melting ice caps due to
global warming.
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(b)
(i) Organisms would have to adapt to increased salinity and reduced land and
habitat. Tolerance limits would be pressured. Plants will possibly die due to
increased salinity and the elimination of change between dry and wet season.
(ii) Soil and water will be affected by increased salt levels; seasons of wet and dry
periods will be impacted.
(c)
8.
Responses will vary. Any reasonable suggestion is accepted.
Across
5. CFC, 8. Ecosystems, 9. Trees, 12. Stratosphere, 15. Denitrifying, 16. Photosynthesis,
17. Methane, 18. Carbon, 20. Biodiversity
Down
1. Population, 2. Hydrosphere, 3. Ozone, 4. Biosphere, 6. Genes, 7. Temperature,
10. Extinction, 11. Lithosphere, 13. Deforestation, 14. DNA, 19. TOMS
9. Responses will vary.
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