A very distinctive biota

When Charles Darwin invited the British botanical artist Marianne North to visit him in 1879, she was delighted. Her intrepid adventures, late in life, travelling the world to paint plants in landscapes had clearly impressed Darwin, and he conveyed to Miss North an important message. She related: ‘He seemed to have the power of bringing out other people's best points by mere contact with his superiority. I was much flattered at his wishing to see me, and when he said he thought I ought not to attempt any representation of the vegetation of the world until I had seen and painted the Australian, which was so unlike that of any other country, I determined to take it as a royal command and go at once’.

The biodiversity of Australia and (to a lesser extent) South America stands out as the most distinctive among the Earth's continents. This has been evident since biologists explored them during the age of European global colonisation and imperialism. Understanding why these biotas are so distinct has occupied many pages of text and produced some very vigorous debates. New approaches and insights now allow us to apply unprecedented scientific rigour to investigating historical biogeography (the distributions of organisms and the factors determining them) and there is growing consensus about how life on Earth has emerged.

This is not to say that all is known. Far from it. There remain extraordinary opportunities still for exploration and major discovery, even in well-settled corners of the planet such as Australia.