Tree of Life Links Earth’s 2.3 Million Species


Scientists from 11 institutions have released the first draft of the Open Tree of Life, an exhaustive project that traces the evolutionary relationships between all of the 2.3 million identified species of plants, animals, microbes and fungi on Earth.

“Understanding how the millions of species on Earth are related to one another helps scientists discover new drugs, increase crop and livestock yields, and trace the origins and spread of infectious diseases such as HIV, Ebola and influenza,” the research team explains in a news release.

The tree of life is effectively a diagram that shows the evolutionary relationships between all living organisms. The branching indicates how different species all descend from a common ancestor. Not just useful for working out how different species are related, they can also be used to assess the origin and spread of infectious diseases, or discover new antibiotics, among other things.


While this initial draft uses data from 500 separate smaller trees, far more data has already been published, accounting for tens of thousands of evolutionary – or phylogenetic – trees. The problem is that only a fraction of those, the researchers estimate about one in six, have deposited their data in a digital, downloadable format that can then be used and added to the single super tree. Most are published as PDFs and other image files that are simply impossible to enter into the new diagram. The researchers see this as the first step in developing the most comprehensive archive of all life on Earth.


The tree is far from complete; much of the evolutionary information required to finish the project is not yet available digitally. Researchers estimate that current digital evolutionary databases contain DNA for less than 5 percent of Earth’s species.

Nonetheless, the completion of the project’s first draft is a major milestone in the democratization of scientific data.

Another major problem that they had to overcome was simply accounting for the changes in names, alternate names, misspellings and abbreviations of species used by different researchers and institutions. Spiny anteaters, for example, once shared their scientific name with a group of moray eels. For this reason the whole project is open access, meaning that anyone can go in and edit the data if and when changes are needed. The researchers refer to it as the “Wikipedia” for evolutionary trees.


The resulting diagram has allowed the researchers to see not just what we know about life on Earth, but what we don’t know too. To fill in these gaps, particularly in the branches that contain the insects and bacteria, they hope to develop software that will allow researchers to enter the tree and add in the data when new species are discovered or named.

“It’s by no means finished,” concludes Cranston. “It’s critically important to share data for already-published and newly-published work if we want to improve the tree.”