Radiation of Australian plants
The Australian fossil record shows that the ancestral Gondwanan rainforest which existed 25 million years ago was mostly replaced over the next 15 million years by the present-day 'sclerophyll' flora dominated by eucalypts and acacias. This change coincided with a cooling, drying climate and the advent of fire. This paper describes how we have used DNA sequence data to compare the patterns and timing of speciation (and extinction) in eucalypts, casuarinas, banksias and legumes. We found that each group speciated rapidly during this period, but only in the drier areas. These similarities across several different lineages suggest that climatic change and ecological factors drove the evolution of the flora, and further support a close link between climate change and evolutionary response.