Scientists have released a new version of the tree of life, showing everything we know about how the living things of Earth are related to one another. With 2.3 million species and counting, it's the most complete model of its kind — but there's a lot more work to do.

[Scientists give yeast human genes to show how much we have in common]

Everything that lives or ever lived on Earth is somehow related to everything else. But figuring out just how all those critters and plants and pond scums fit together has posed a bit of a challenge. There are a lot of Earthlings, after all, and with around 15,000 species discovered each year, our family tree keeps getting bigger and more complicated all the time.


This circular family tree of Earth's lifeforms is considered a first draft of the 3.5-billion-year history of how life evolved and diverged. (opentreeoflife.org)

That's why the researchers, who reported their new tree on Friday in the Proceedings of the National Academy of Sciences, have open-sourced the model, making it free to download online. This is simply version 1.0, and they're going to need help with revisions.

The first draft combined around 500 existing trees to come close to true completion. But close is a relative term here.

One popular study estimated a staggering 8.7 millions of species on Earth today, let alone in the planet's entire history. There are a lot of gaps we've yet to fill in. And the relationships between different species aren't always easy to pin down, so some are controversial or just totally mysterious.

"As important as showing what we do know about relationships, this first tree of life is also important in revealing what we don't know," co-author Douglas Soltis of the University of Florida said in a statement.

The researchers hope that other scientists will help finish the job by uploading their own data.

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