Unit 3 AOS1
Plate Tectonics: ⁃ Pangaea ⁃ 160 million years ago Pangaea split forming Laurasia and Gondwana
3 factors that have influenced the evolution of Australia…
Biological Isolation:
Flora and fauna has been able to adapt over millions of years in isolation. It has been able to adapt without the influence of predators. That is why Australian fauna is very susceptible to introduced species.
EG. The fact that Kangaroos have roamed around for many years without predators.
Geological Isolation:
Due to the land not being refreshed regularly from instability (volcanic action) the land is generally very old with poor nutrients. Soils have also been subjected to wind and water erosion, washing away topsoil nutrients. The state of soils influence flora and fauna and due to this, they have been able to develop without nutrients and have become extremely energy efficient. Biodiversity can be very high due to one species not being able to dominate a particular environment.
Climatic Variations:
Australia's weather has fluctuated die to its size and position on Earth. There have been fluctuations in temperature and in sea levels and periods of aridity which had changed Australia's biodiversity over many years. The erratic climate can affect the reproduction cycles and survival rates of the flora and fauna.
EG. Koalas have adapted with the changing nature of the Australian environment over time. They now have "re-shaped" faces to better cater for eating from Eucalyptus trees and communication. Brain is smaller for efficient energy.
Fire: Australia has become a drier land. Arid areas increased the incident of naturally occurring bush fires. Fire has saw some areas replaced with grasslands replacing lush understory such as ferns and a general thinning out of woodlands and the replacement of fire hardy trees. Certain plant species have adapted so much to the fire cycle, that their seeds only get a chance to germinate