Online ‘Open Tree of Life’ Traces Origins of 2.3 Million Species

The combined efforts of thousands of scientists worldwide have produced the most complete "tree of life" yet, showing the evolutionary heritage of 2.3 million species from amoebas to aardvarks -- and it's free for everyone to browse online.

Such trees are common in the field of biology, with branches showing how and when one species or class differentiated relative to others over the course of history. But most such trees are limited to a handful of creatures, like dogs or the ancestors of modern humans. This one starts from the very top, where the most fundamental differences in life on earth are reflected, and goes down to the very bottom, where even experts may have trouble telling two species apart.

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"This is the first real attempt to connect the dots and put it all together," said Duke University's Karen Cranston, who led the effort, in a news release. "Think of it as Version 1.0."

Despite combining information from over 500 smaller trees, the Open Tree of Life is by no means complete, for several reasons. For one thing, only a fraction of the tens of millions of species estimated to exist are described in online research they could build into the database, making them suitable for inclusion. And even a "complete" tree would soon be made obsolete as researchers debate and revise relationships between organisms.

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But by making the online tree free to use and publicly editable, like Wikipedia, its creators hope the tool will stay valuable and relatively up to date. Students and people unfamiliar with phylogenetic trees might want to start with the less technical educational site.

"Twenty five years ago people said this goal of huge trees was impossible," said co-author Douglas Soltis, of the University of Florida. "The Open Tree of Life is an important starting point that other investigators can now refine and improve for decades to come."