Island ecology in the context of Exotic species

Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species.

Examples of vestigial structures (also called degenerate, atrophied, or rudimentary organs) are the loss of functional wings in island-dwelling birds; the human vomeronasal organ; and the hindlimbs of the snake and whale.

The Australian environment ranges from virtually pristine Antarctic territory and rainforests to degraded industrial areas of major cities. Forty distinct ecoregions have been identified across the Australian mainland and islands. Central Australia has a very dry climate. The interior has a number of deserts while most of the coastal areas are populated. Northern Australia experiences tropical cyclones while much of the country is prone to periodic drought. This dry and warm environment and exposure to cyclones, makes Australia particularly vulnerable to climate change -- with some areas already experiencing increases in wildfires and fragile ecosystems.

The island ecology of Australia has led to a number of unique endemic plant and animal species, notably marsupials like the kangaroo and koala. Agriculture and mining are predominant land uses which cause negative impacts on many different ecosystems. The management of the impact on the environment from the mining industry, the protection of the Great Barrier Reef, forests and native animals are recurring issues of conservation.