week 9

Question 1

What were megafauna?

Answer 1

large animals that occupied many ecosystems prior the
last glacial period. Now only left in large numbers in Africa

Question 2

When did the megafaunal extinction occur in Australia?

Answer 2

around 42,000 years ago,
although extinctions had been occurring earlier, and some species persisted for longer.

Question 3

What are the hypotheses on what caused the megafaunal extinction?

Answer 3

Humans
Climate
A combination of humans and climate

Question 4

What are the different variations of the human cause of extinction?

Answer 4

Overkill
Innovation
• Environmental modification
• Attrition

Question 5

What is the Overkill hypothesis?

Answer 5

– humans arriving in a new landscape targeted the vulnerable prey

Question 6

What is the Innovation hypothesis?

Answer 6

– humans adopting new technology to better hunt megafauna

Question 7

What is the Environmental modification hypothesis?

Answer 7

• Humans modified the landscape to put megafauna at a disadvantage.
• The use of fire changed vegetation communities
• Particularly important for herbivore species

Question 8

What were Australia’s climate changes similar to?

Answer 8

Changes generally more similar to Antarctica than
Greenland

Question 9

where were Glaciers in Australia?

Answer 9

Glaciers were confined to small areas in the
Tasmanian highlands and the Snowy Mountains

Question 10

What happened in Australia during the deglaciation?

Answer 10

• Increase in woody taxa and Eucalyptus across
eastern Australia
• Changes generally more inline with Antarctica than
Greenland

Question 11

What where the features of the Antarctic Cold Reversal in Tasmania?

Answer 11

• Enhanced westerly winds and northward migration
• Increased windspeed across Tasmania
• Western Tasmania: Enhanced rainfall and reduced biomass burning
• Eastern Tasmania: Enhanced evaporative conditions
• No evidence for readvance of glaciers

Question 12

What is Kati Thanda (Lake Eyre) levels an example of?

Answer 12

Example of insolation forcing on Australian climate through the Australia Summer Monsoon

Question 13

When had ice in australia melted by?

Answer 13

~16,000 years ago

Question 14

What is the definition of megafauna?

Answer 14

big animals > 45 kg

Question 15

How many genera of megafauna before and after extinction?

Answer 15

Prior to 50,000 year ago there were 150 genera of mammals larger than 45 kg. By 10,000 years there were 50 or fewer genera

Question 16

What is the Attrition hypothesis for megafaunal extinction?

Answer 16

Humans slowly drive megafauna to extinction, through
hunting, habitat modification and competition for
resources

Question 17

Which theories on megafaunal extinction would be favoured by humans and megafauna coexisting for a long time?

Answer 17

climate change
Innovation
Attrition

Question 18

Which theories on megafaunal extinction would be favoured by humans and megafauna not coexisting for a long time?Why?

Answer 18

Overkill hypothesis
requires humans to be a novel predator

Question 19

What is the theory that Climate change drove the megafauna to extinction?

Answer 19

• Extinctions occurred following climate changes that
the megafauna were not able to survive
• In Australia, an increase in arid conditions over the
last 430,000 years meant that conditions eventually
became too extreme for the megafauna.

Question 20

What is the theory that Both climate change and humans drove the megafauna to extinction?

Answer 20

• Pressure from both humans, through hunting and
landscape modification
• With reduced freshwater, people and megafauna
would have congregated around areas of freshwater, increasing the chance of encounters and hunting

Question 21

Did humans a megafauna likely coe exist what was the likely cause? What is this evidence against?

Answer 21

• Humans and megafauna co-existed for ~17,000
years, at least in some regions
Evidence against the overkill hypothesis

Question 22

Can climate change explain the megafauna extinction in australia?

Answer 22

No Most evidence suggests that the Australian climate
was relatively stable during periods of extinctions

Question 23

Is there evidence that climate change did cause the megafauna extinction in australia?

Answer 23

Yes, Extinctions were already in place well before humans arrived in Australia

Question 24

When was the last glacial maximum in australia?

Answer 24

• Earlier date than in Northern
Hemisphere, including Greenland
• ~28 ka

Question 25

What were the conditions of the LGM in australia?

Answer 25

wide spread aridity
• Extensive dune systems
• Higher dust flux in surrounding ocean sediment