Charles Darwin's Controversial 'Jump Dispersal' Theory May be True

Charles Darwin once hypothesized that species could cross oceans by hitchhiking on rafts made out of vegetation, icebergs, and even flying in the plumage of birds. Now, scientists have found new evidence supporting this "jump dispersal" idea, telling researches a bit more about the spread of species.

Scientists have long wondered how species dispersed across the planet, coming to live where they are now. Called biogeography, this field of study has long been debated among biologists-especially when it comes to organisms that are related but live on distant continents. Some examples include the Australian emu and the African ostrich. That's why researchers decided to create a computational method to test two competing theories on species dispersal.

The new research compares jump dispersal and vicariance, which is the idea that land bridges served as connecting points when islands were contiguous. Using data from many species that live in the Hawaiian Islands and on other archipelagos, the scientists found that jump dispersal was able to explain the biogeography of the species with far greater statistical probability.

"Conventional biogeography said vicariance was a more scientific explanation than jump dispersal because vicariance relied on normal, predictable processes, and jump dispersal relied on extremely rare, near-miraculous events," said Nicholas Matzke, one of the researchers, in a news release. "Now the shoe is really on the other foot because the jump dispersal pattern appears to be much more common. It looks like Darwin was right after all."

The findings reveal that jump dispersal could help scientists accurately reconstruct evolutionary history.

"Jump dispersal helps us remember that events that are rare on human timescales can be common over geological timescales, and that biodiversity might be structured largely by these rare chance events," said Matzke.

The findings are published in the journal Systematic Biology.