Lecture Seventeen - Evolution and biogeography of the Australian fauna I Flashcards
What are the three biogeographic areas of Australia?
What are the main factors that control the climate of Australia?
Rainfall.
Hadley cells.
Circulation cells.
Coriolis effect.
Rain shadows.
Ocean currents.
Sea surface temperature.
Elevation.
Topography.
Southern oscillation.
Rain fall variability.
What influences rainfall?
Latitude.
Atmospheric and oceanic currents.
Water temperature of surrounding ocean.
Topography of land mass.
What are Hadley cells and circulation cells?
Hadley cells:
Upwelling of moist air at equator.
Moisture falls as rain.
Dry air travels at high altitudes and descends at 30 degrees.
High rainfall at equator, low at 30 degrees.
Circulation cells:
Threec ells in each hemisphere.
High rainfall at 60 degrees low at poles.
Australia has crossed 30 degrees latitude over the last 60 million years.
What is the coriolis effect?
Rotation of Earth affects air currents.
North of the equator - winds deviate to the right.
South of the equator - winds deviate to the left.
What is a rain shadow?
Moist air cools as it rises over mountain.
Orographic rain on west side.
Describe the circumpolar current.
Break up of Gondwana influenced direction and intensity of ocean currents.
Isolation of Antarctica created circumpolar current - prevents warm equatorial currents travelling further south.
What ocean current effect Australia’s climate?
The current travelling from the North (equator) down the East cost of Aus causes rain due to the air it carries beign warm and humid.
The current travelling from the South (Antarctica) up the West cost of Aus causes WA to be very dry, as the air that water carries is cool and dry.
Describe El Nino and La Nina.
Southern oscillation - varyation of Pacific Ocean surface temperature every 3-8 years.
El Nino:
- Eastern Pacific is warm.
- Low rainfall in Aus.
La Nina:
- Western Pacific is warm.
- High rainfall in Aus.
What were the major events in the Earth history (in geologic terms).
What are some terms to describe different species distributions?
Endemic species = restricted to given land mass.
Cosmopolitan species = widespreads.
Vicariance = seperated by geographic barrier.
Dispersal = spread out from origin.
What are examples of species which formed in different gological times.
When South America, Africa and Australia were joined:
- Lung fish.
- Leptodactylid frongs (burrowing frogs).
- Long necked tortoises (pleurodires).
- Ratite birds.
When South America and Australia were joined:
- Hylid frogs.
- Horned turtles.
- Parrots.
- Marsupials.
Who was Alfred Wallace and what did he do?
British naturalist.
Co-discoverer of natural selection.
Father of biogeography.
Fieldwork in Indonesia.
Where is Wallace’s line?
Wallace’s line:
A hypothetical line, proposed by Alfred Russel Wallace, marking theboundary between the Oriental and Australian zoogeographical regions. Wallace’s line is now placed along the continental shelf of SE Asia. To the west of the line Asian mammals predominate, while to the east of it the fauna is dominated by marsupials.
