Download 4.1 Gondwana – Further questions Q1. Bk Ch4 S4.1 FQ1 a What do

4.1 Gondwana – Further questions
Q1.
Bk Ch4 S4.1 FQ1
a
b
What do we mean when we say that Australia is an ‘island continent’?
Discuss the significance of this idea in terms of the evolution of Australian flora and fauna.
A1.
Bk Ch4 S4.1 FA1
a
b
Australia’s status as an island continent refers to its isolation from other landmasses.
Australia’s long isolation from other landmasses is a significant factor contributing to the
evolution of its unique flora and fauna. Environmental conditions in Australia over millions of
years coupled with the reproductive isolation of plants and animals has resulted in organisms that
are unique in the world.
Q2.
Bk Ch4 S4.1 FQ2
a
b
c
Use a current topographical map of the world to mark the positions of mid-ocean ridges and
spreading zones.
Explain how mid-ocean ridges and spreading zones are formed.
Outline the relationship between these two different features.
A2.
Bk Ch4 S4.1 FA2
a
Example diagram:
b
Mid-ocean ridges are present on the ocean floor along the boundaries where tectonic plates meet.
There is an up-welling of the semi-molten rock within the mantle that rises to the surface as lava
between tectonic plates at this boundary. As the lava reaches the surfaces along the boundary line
it flows out forming a peak or ridge and cools to become new crust. As new crust continues to be
formed the ocean floor on each side of the ridge is forced further and further apart, spreading the
newly formed ocean floor over greater and greater distances. This is a spreading zone.
A mid-ocean ridge is the ridge formed when molten rock wells up through the Earth’s crust
between two tectonic plates. A spreading zone is the area on either side of the ridge characterised
by the continuous moving apart or spreading of the tectonic plates as new crust is formed at the
ridge. Eventually the edges of ridge move apart, becoming the spreading zone.
c
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Q3.
Bk Ch4 S4.1 FQ3
a
b
c
Based on our current understanding of the movement of tectonic plates, outline the predicted
future positions of global topographical features, including the continent of Australia.
Suggest the changes that are likely to occur to Australia’s climate as a result of its changing
position.
What impacts might these have on Australia’s flora and fauna?
A3.
Bk Ch4 S4.1 FA3
a
b
c
Predictions based on current understanding of plate tectonics indicate that over the next 50 million
years the joined continents of North and South America will move further westward causing the
Atlantic Ocean to widen and the Pacific to contract; Africa will move into closer proximity with
Europe, and Australia will move further northward, positioned about the Equator and possibly
push into Asia.
As Australia moves northwards towards the equator its climate can be expected to alter.
Continental temperatures would be expected to increase with an increase in rainfall and humidity,
particularly in coastal regions.
Any significant change in climate can be expected to impact on the flora and fauna of a region.
Plants and animals that are adapted to Australia’s current environmental conditions may not be
able to adapt to a new set of conditions. If this occurs we could expect extinction to occur for at
least some species. Species that are able to adapt may not be recognisable in 50 million years.
Q4.
Bk Ch4 S4.1 FQ4
Find out why Australia does not experience many severe earthquakes.
A4.
Bk Ch4 S4.1 FA4
Australia is about in the middle of the Indo-Australian tectonic plate. Its continental boundaries are far
from the edges of the tectonic plate so it experiences little in the way of dramatic earth movement such
as earthquakes that are associated with tectonic plates moving against one another.
Q5.
Bk Ch4 S4.1 FQ5
The cassowary (northern Australian and New Guinea), Australian emu, New Zealand kiwi, South
American rhea and African ostrich are all flightless birds that are native to different parts of the
southern hemisphere. DNA testing suggests a genetic relationship between the different species.
a
What conclusions can be drawn from this information?
b
Use the information accompanying Figure 4.6 to draw an evolutionary tree for these flightless
birds.
A5.
Bk Ch4 S4.1 FA5
a
b
If DNA testing suggests that there is a genetic relationship between the different species of birds
then one can conclude that at some time in their evolutionary history they shared a common
ancestor.
Evolutionary tree:
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Q6.
Bk Ch4 S4.1 FQ6
Explain how Australia’s isolation from other landmasses can be used to account for the large number
of endemic species of plants and animals.
A6.
Bk Ch4 S4.1 FA6
Australia has been isolated from the other landmasses to which it was once joined for the last 45
million years. Its geographical isolation has meant reproductive isolation for the plants and animals that
live here. With changing environmental conditions this isolation has led to the evolution of uniquely
Australian species, for example the wide variety of marsupial species, the monotremes and unique bird
life, such as emu and various species of parrots; flora include the many species of eucalypt.
Q7.
Bk Ch4 S4.1 FQ7
What does the existence of living fossils suggest about the environment in which they live?
A7.
Bk Ch4 S4.1 FA7
Considering that species tend to undergo change when they are subject to changing environmental
conditions, the existence of living fossils suggests that the particular environment of the organisms has
been relatively static over time.
Q8.
Bk Ch4 S4.1 FQ8
Research the work of Tim Flannary and/or Michael Archer in relation to Australia’s fossil history.
A8.
Bk Ch4 S4.1 FA8
Answer will depend on the palaeontologist chosen.
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© Pearson Australia (a division of Pearson Australia Group Pty Ltd)