Deck 46: Human Impacts

Question 1

Australian bats and rodents

A) are unique because they have a Gondwanan origin.
B) were exchanged with Asian islands as the Australian plate approached the South-East Asian plate.
C) evolved in Australia in isolation just after its separation from Gondwana.
D) evolved in response to Australia's increasingly arid climate during the Tertiary.
E) were brought here about 40 000 years ago by people.

Answer 1

were exchanged with Asian islands as the Australian plate approached the South-East Asian plate.

Question 2

Declines in abundance and range of native Australian flora and fauna have been highest in

A) agricultural areas.
B) regions where settlement first occurred.
C) forests.
D) heavily wooded country.
E) arid desert of central Australia.

Answer 2

regions where settlement first occurred.

Question 3

What proportion of forests present when Europeans arrived in Australia is still here?

A) 100 per cent
B) 80 per cent
C) 50 per cent
D) 25 per cent
E) 10 per cent

Answer 3

50 per cent

Question 4

Which of the following statements about human impacts on Australian ecosystems is true?

A) The rate of species extinction has levelled out.
B) Accelerated rates of extinction are expected particularly for birds.
C) Many species have declined in abundance but not in range.
D) While many bird species have become extinct, the impact of humans is not significant on the mammalian species.
E) All of the answers are true.

Question 5

One problem with identifying biodiversity hotspots is that

A) sites of endemism and richness may not occur in the same place.
B) sampling efforts are not extensive enough.
C) they are variable in what is identified as rich.
D) they are difficult to find.
E) some species are considered more important than others.

Question 6

Frugivorous cassowaries are threatened by rainforest clearing in Queensland. A likely consequence of the disappearance of these birds is that

A) many tree species will not be able to disperse.
B) emus will move in to fill the vacant niche.
C) the fruits they eat will be available for other animals, so the diversity will change.
D) the understory will become denser as grazing pressure declines.
E) there will be rapid speciation in other areas.

Question 7

Tropical rainforest covers

A) > 50 per cent of the earth's surface and contains about 10 per cent of all species.
B) about 50 per cent of the earth's surface and contains about 70 per cent of all species.
C) about 20 per cent of the earth's surface and contains about 80 per cent of all species.
D) about 10 per cent of the earth's surface and contains about 10 per cent of all species.
E) < 10 per cent of the earth's surface and contains about 50 per cent of all species.

Question 8

In rainforests,

A) gaps created by tree falls and forest fires are insignificant.
B) the slash-and-burn agriculture of indigenous Amazonians has the same impact as naturally occurring gaps.
C) clearing creates soils capable of supporting productive pasture for very long periods of time.
D) there is rapid nutrient recycling back to the living biomass.
E) are a very stable ecosystem, maintained by decomposers and bacteria.

Question 9

In fragmented habitats

A) larger species of animal are more likely to survive than smaller species.
B) most patches are small enough to support viable populations of all resident species.
C) habitat corridors linking adjacent fragments can increase effective fragment size.
D) the size and shape of remnant patches has no impact on species survival.
E) small animals are more vulnerable than large animals.

Question 10

In general, narrow remnant vegetation along roads

A) makes good wildlife refuges for large animals.
B) shows uniform species composition from one side to the other.
C) favours the survival of species found in the interior of fragments.
D) has a high edge:area ratio.
E) provides little protection for small organisms.

Question 11

Habitat corridors

A) promote the exchange of genes between subpopulations.
B) inhibit the spread of weeds and diseases.
C) promote animal migration when they are long and narrow.
D) threaten the biodiversity of the area.
E) inhibit animal migration when they are wide.

Question 12

Rabbits contribute to rural dieback in the mallee ecosystems of Victoria primarily by

A) eating regenerating seedlings.
B) ring-barking trees.
C) favouring the spread of introduced grasses.
D) disturbing roots and killing shrubs by burrowing.
E) spreading diseases that attack normal seed vectors.

Question 13

The cane toad

A) is not a considered to be a pest species within Australia.
B) has a very specific diet.
C) has no effect on native wildlife.
D) lack of natural predators.
E) continues to spread throughout parts of Australia.

Question 14

Dandelion, Taraxacum officionale, is a typical weed species. You would expect it to have all of the following characteristics EXCEPT

A) fast growth.
B) the ability to colonise disturbed habitats.
C) exclusively sexual reproduction.
D) good competitive ability.
E) early flowering.

Question 15

Threatening processes in freshwater systems do NOT include

A) pollution.
B) changes in water temperature.
C) low oxygen levels.
D) sunlight.
E) sandy soil.

Question 16

Erosion in degraded ecosystems is primarily caused by

A) clearing of land for agriculture and cultivation.
B) frequent fires.
C) over-grazing.
D) pasture die-back.
E) All of the answers are correct.

Question 17

Soil in tree-dominated ecosystems is

A) stabilised by plant roots.
B) particularly susceptible to erosion because it has a covering of litter.
C) subject to high wind velocity due to vegetation cover.
D) susceptible to erosion due to burrowing rabbits.
E) typically compacted with slow rates of rainwater absorption.

Question 18

Induced soil acidity in Australia

A) is a recent land degradation problem.
B) is not a significant problem.
C) is improved by the addition of ammonia-based fertilisers.
D) has been caused by the addition of lime.
E) only occurs in mangrove swamps.

Question 19

Which of the following statements about salt in Australian rural landscapes is true?

A) High levels of salt are mainly found in wetter regions.
B) Clearing allows the water table to rise, carrying salts.
C) Salt is only a problem when it forms scalds on the surface.
D) Salt in ground water is a problem as it stunts root growth.
E) Salinity is not a significant problem in Australia.

Question 20

The most efficient way of managing dryland salinity is

A) clearing, to allow water to enter recharge zones.
B) switching to shallow-rooted crops to avoid pulling water to surface.
C) irrigating, to flush out salt.
D) revegetating land with deep-rooted plants to lower the water table.
E) planting of crops that require little water.

Question 21

Which of the following statements about the ozone layer and ultraviolet light is true?

A) Nearly all UV-A is screened out by the ozone layer.
B) For each 1 per cent decrease in ozone, UV-B reaching the earth's surface increases by 2 per cent.
C) Chlorofluorocarbons (CFCs) react with ozone in a reversible reaction.
D) The thinning of the ozone layer is most pronounced in the tropics.
E) UV-C has the longest wavelength and is poorly absorbed by the ozone layer.

Question 22

Which of the following statements with regards to the role of phytoplankton is NOT true?

A) Phytoplankton scatter and absorb light entering the water.
B) Phytoplankton productivity increases with increasing UV radiation.
C) Phytoplankton release volatile organic compounds to help clouds form.
D) Phytoplankton fix atmospheric carbon dioxide.
E) Phytoplankton is a small autotrophic organism which in large numbers may cause green colouration on water.

Question 23

In the greenhouse effect, incoming solar radiation entering the earth's atmosphere is

A) absorbed by greenhouse gases in the upper atmosphere.
B) re-radiated as short wave radiation from the earth's surface and is reabsorbed by the atmosphere.
C) re-radiated directly into space.
D) re-radiated as heat from the earth's surface and is absorbed by atmospheric gases.
E) trapped in the lower atmosphere by carbon dioxide.

Question 24

CO₂ is a significant greenhouse gas. The greatest gains in CO₂ reduction would be achieved by

A) increasing the rate of land clearing.
B) reducing the number of domesticated cattle.
C) reducing the use of fossil fuels, particularly oil and coal.
D) limiting the use of renewable, non-carbon based forms of energy.
E) planting trees which fix carbon dioxide in photosynthesis.

Question 25

Coral bleaching is an indication of rising sea temperatures and increased levels of solar radiation. Coral bleaching

A) has been observed in very few countries in the Caribbean, Indian and Pacific Oceans.
B) has affected up to 88 per cent of near-shore corals in the Great Barrier Reef.
C) is unlikely to be of increased significance on the Great Barrier Reef in the future.
D) only occurs at locations near the equator where the sea temperature is highest.
E) All of the answers are true.

Question 26

Some rare and endangered Australian parrots are frequently found for sale in Singapore. Attempts to prevent this trade in exotic wildlife, which threatens biodiversity, is under the control of the

A) Convention on International Trade in Endangered Species.
B) Native Flora and Fauna Guarantee Act.
C) Environmental Protection Act.
D) World Heritage Act.
E) Australian Customs.

Question 27

The main difference between aboriginal (pre-European) and European burning regimes in Australia, was that

A) Aborigines used extensive, intense wildfires.
B) Aborigines burnt regularly but in patches.
C) Europeans used regular, intense burning on a small scale.
D) Aborigines did not deliberately light fires.
E) Europeans burn only in winter.

Question 28

The advantage of burning in a patchwork mosaic, in fire management regimes in coastal heath environments, is that it

A) provides a range of habitats.
B) maintains species diversity.
C) allows a sequence of plant successions.
D) is more easily controlled.
E) All of the answers are advantages.

Question 29

Which of the following is the best definition of the aims of ecologically sustainable development? Ecologically sustainable development aims to

A) limit environmental degradation.
B) limit resource use.
C) use, conserve and enhance resources and maintain ecological processes.
D) adopt the precautionary principle in policy making.
E) ensure that development by humans remains within the limitations of the ecology of the environment.

Question 30

Declines in abundance of flora and fauna in the regions first settled is attributable to

A) inappropriate land use.
B) spread of exotic herbivores.
C) habitat loss and fragmentation.
D) over-exploitation of fresh-water.
E) All of the answers are correct.

Question 31

Biodiversity is

A) the variety of life forms.
B) the diversity of genes.
C) the diversity of ecosystems.
D) the diversity of oceans.
E) All of these answers are part of biodiversity.

Question 32

Many significant hotspots of biodiversity have been identified in Australia. One of these is

A) south-west of Western Australia.
B) the grasslands of Victoria.
C) tropical rainforests of the Northern Territory.
D) the sclerophyll forests of Queensland, home to bats.
E) coastal New South Wales.

Question 33

The total extent of National Parks and Reserves has increased since 1968 and is now

A) 0.5 million hectares.
B) 1 million hectares.
C) 4 million hectares.
D) 10 million hectares.
E) 40 million hectares.

Question 34

Which of the following is NOT a reason to conserve biodiversity?

A) Organisms are essential for ecosystem survival.
B) We need many different organisms to maintain or lifestyle.
C) Biodiversity provides enjoyment through complexity and aesthetics.
D) Each country has its own individual cultural biodiversity.
E) From an ethical point of view we should support survival of the fittest.

Question 35

Rainforest ecosystems are characterised by

A) frequent natural disturbance.
B) rapid nutrient recycling.
C) high abundance of decomposers such as fungi.
D) dense root systems which prevent erosion.
E) All of the answers are correct.

Question 36

Feral animals

A) are animals that are a pest.
B) are never domestic animals.
C) are not a problem when introduced for bio-control of noxious species.
D) may damage vegetation and soil.
E) are not in competition with native animals for food.

Question 37

In which areas are Australian ecosystems currently under the most threat from human activities?

A) Pastoral
B) Tropical
C) Coastal
D) Agricultural
E) Residential

Question 38

It is widely accepted that sometime around 10 000 years ago cheetahs went through a severe genetic bottleneck. As a result of this, the biodiversity of their ecosystems has

A) decreased significantly.
B) increased slightly.
C) increased significantly.
D) remained unchanged.
E) decreased slightly.

Question 39

At current rates of tropical deforestation, the percentage of tropical forest species that will become extinct per decade is thought to be between

A) 2-5%.
B) 10-15%.
C) 15-20%.
D) 25-35%.
E) 5-10%.

Question 40

What size organisms are particularly affected by habitat fragmentation?

A) All organisms are equally affected by habitat fragmentation, irrespective of their size
B) Microscopic
C) Small
D) Medium
E) Large

Question 41

Which of the following is NOT a common characteristic of a successfully invading new species?

A) High mobility
B) High survival rate
C) Low fecundity
D) Lack of predators
E) Broad diet

Question 42

Two farmers grow identical crops on adjacent land. One uses a traditional chemical fertiliser regime to maximise his agricultural output, whereas the other uses microorganic bio-fertilisers and crop rotation to minimise his use of chemical fertilisers. The first farmer who uses a traditional chemical fertiliser regime initially has higher yields with less effort, but over time his yields start to drop and continue to do so while the second farmer maintains a consistent output. What might be causing the drop in yield for the first farmer?

A) Soil acidification
B) Soil erosion
C) Sodic soils
D) Soil alkalinity
E) Ion toxicity

Question 43

The earth's ozone layer absorbs damaging UV radiation, thus protecting us from its most harmful effects. There are several different types of UV radiation which are defined according to their respective wavelengths. UV is also used to create sterile working areas; which UV would be best suited for this application?

A) UV-A
B) UV-B
C) All UV radiation is equally damaging, therefore any UV wavelength could be used
D) UV-D
E) UV-C

Question 44

Which of the following measures would help to reduce the emission of greenhouse gases into the atmosphere?

A) Burning garbage instead of coal for electricity generation
B) Using plain toilet paper instead of printed
C) Drinking diet-coke instead of coke-zero
D) Reducing the levels of flatulence in livestock
E) Flying to work in individual helicopters or jets instead of driving

Question 45

How does the new national Carbon Farming Initiative help to reduce greenhouse gas emissions?

A) It pays the least efficient farmers a grant to leave farming.
B) Farmers and land managers earn carbon credits by increasing stock levels.
C) Farmers and land managers earn carbon credits by switching to GM crops.
D) Farmers earn a 13 per cent feed-in tariff for permitting the construction of wind turbines or industrial-scale solar generation on their land.
E) Farmers and land managers earn carbon credits by reducing greenhouse gas emissions and/or storing carbon on the land.