BIO3132 Lecture Notes - Lecture 1: Tantrum, Great Dividing Range, Norther
31 May 2018
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Week 1. Biogeographical History of Australia and
Habitat Selection
BIOGEOGRAPHICAL HISTORY OF AUSTRALIA
Lecture objective:
Gai a uderstadig of the fators that hae shaped the eolutio ad distriutio of Australia’s
vertebrate fauna
• Australia has a mixture of highly unusual endemic taxa and species that belong to huge and
globally distributed groups
• Many endemics (not found anywhere else) such as kangaroos which are only found in Australia
and the New Guinea
• Many global groups that have high diversity elsewhere have low diversity or are absent in
Australia
• We have living fossil groups that are extinct elsewhere
• We lack some functional groups such as open country carnivores
• Why are there tigers and elephants in South East Asia but tree kangaroos and echidnas in
Australasia?
o Why is there a distinct line
• Importance of historical factors:
o Island continent = isolation = very high levels of endemism (1st aog the orld’s
countries in terrestrial vertebrates)
- keeps out other taxas
o Tectonics and ocean currents = variable and extreme climates = selection for
opportunistic life-histories
find more resources at oneclass.com
find more resources at oneclass.com
o No ice age glaciers = low soil nutrients = unique flora = unique herbivorous fauna
-glaciation causes soil to have high nutrients -> implications to vegetation
o Human colonisation = extinctions + introduction of dingoes + fire and land clearing
• Geological history:
o Pangaea:
300 mya = end of the age of amphibians (fairly cold time)
290 a = largest ass etitio i Earth’s histor
280 mya = diversification of reptiles
260 mya = mammal like reptiles
240 mya = first dinosaurs, first mammals (warm period, distinct green and
brown bands)
220 mya = age of dinosaurs
200 mya = age of dinosaurs and first birds
170 mya = age of dinosaurs
o Laurasia and Gondwana
150 mya = age of dinosaur (angiosperm = wave of insects)
-huge runaway effect of diversification
-Gondwana is moving south
148 mya = archaeopteryx
140 mya = first flowers
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find more resources at oneclass.com
120 mya = age of dinosaurs, angiosperms diversify, radiation of insects)
o Breaking up of continents:
105 mya = age of dinosaurs
90 mya = age of dinosaurs
o Extinction of dinosaurs
65 mya = K-T boundary, early insectivorous mammals and primates
o Modern continents:
50 mya = formation of grasslands, radiation of mammals and birds
-as Australia moves North it becomes more brown/dry
35 mya = browsing mammals and monkey-like primates, many modern genera
of plants
20 mya = spread of grasslands, forests contract, grazing animals and apes
Modern day
5.2 mya = aridity, deserts
1.6 mya = 24+ glacial epochs
0.01 mya = age of humans
• Australian climate has been cycling through wet and dry periods for at least 500,000 years
-not well understood why but appears to be connected to glacial and inter-glacial epochs
• Isolation from Gondwana
1. Warm period towards South Pole -> 2. Moves north (gets drier) -> 3. Animals have to adapt to
hot desert environment -> 4. People arrive (immigrants)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Australia: we have living fossil groups that are extinct elsewhere, we lack some functional groups such as open country carnivores, why are there tigers and elephants in south east asia but tree kangaroos and echidnas in. Australasia: why is there a distinct line. Island continent = isolation = very high levels of endemism (1st a(cid:373)o(cid:374)g the (cid:449)orld"s countries in terrestrial vertebrates) Keeps out other taxas: tectonics and ocean currents = variable and extreme climates = selection for opportunistic life-histories, no ice age glaciers = low soil nutrients = unique flora = unique herbivorous fauna. Glaciation causes soil to have high nutrients -> implications to vegetation: human colonisation = extinctions + introduction of dingoes + fire and land clearing, geological history, pangaea: 300 mya = end of the age of amphibians (fairly cold time) 290 (cid:373)(cid:455)a = largest (cid:373)ass e(cid:454)ti(cid:374)(cid:272)tio(cid:374) i(cid:374) earth"s histor(cid:455) 240 mya = first dinosaurs, first mammals (warm period, distinct green and brown bands)
