UF team helps fulfill Darwin's vision: Tree of Life contains the 2.3 million named species on Earth
Charles Darwin, the father of modern biology and author of the theory of natural selection, wrote about the Tree of Life in his revolutionary landmark book On the Origin of Species in 1859. His vision was a reference containing every named species on Earth illustrating how they were all interconnected to a common ancestor.
It has challenged biologists ever since.
“That’s been the Holy Grail. Could we build a tree of life?” said Doug Soltis, a University of Florida botanist and director of the Laboratory of Molecular Systematics and Evolutionary Genetics.
One hundred and fifty-six years later, Soltis and a team of scientists at universities around the country have done just that: created a Tree of Life containing the 2.3 million named species on the planet.
Darwin might say, “What took you so long?”
Even 20 years ago, colleagues scoffed. The biggest tree anyone had published in 1990 had 500 species.
“People thought it was ridiculous,” Soltis said.
Four years ago, the National Science Foundation sent out a call to participate in the Idea Lab. Soltis teamed up with 15-20 researchers at 11 other universities, each working on their own areas of specialization. The project cost $6 million, of which UF got around $800,000.
For Soltis and his team, it was plant biology. Other teams focused on mammals, birds, insects, bacteria and other microorganisms.
Three things made it all possible, Soltis said: the creation of a special algorithm that could embrace the exponentially spiraling number of possibilities, the DNA revolution that gave scientists the code to linking species, and supercomputers that could crunch all that data.
Soltis and his team used UF’s HiPerGator extensively.
One branch alone, containing all the species related to the Rosales group, runs to 5,700 species. When Soltis rolls out the branch on the floor of his lab inside Dickinson Hall, it runs at least fifty feet.
A printout containing all 2.3 million named species would run 400 times that long, or 4 miles. Soltis would have to stand at the summit of Mt. Kilimanjaro to unfurl such a document.
“I don’t think people appreciate how big this Tree of Life is,” he said.
And those are just the named species. Scientists estimate another 10 million unnamed species exist on Planet Earth.
“Discovery is a big part of biodiversity, getting all these other species,” Soltis said. “We still don’t know a lot about our planet.”
Even in Florida, scientists are discovering new plant life.
The Tree of Life is key to understanding and recording all of Earth’s biodiversity — and having it organized and ordered in one place. Soltis sees it as fueling future investigations and discoveries.
It also has practical applications in the world of medicine. Researchers using the Tree of Life will be able to develop vaccines for the flu and other illnesses.
“Think of your own family tree,” he said. What it tells us about ourselves is the key to knowing our own risk of heart disease or cancer.
The tree has agricultural benefits, too, identifying the wild plants from which crops were cultivated.
And scientists can use the tree to measure the effect of climate change on plants, animals and other organisms. “This will be a major tool in studying how plants and organisms will respond to climate change,” Soltis said.
The tree isn’t finished. It keeps growing with each new discovery, Soltis said, much like the Human Genome Project.
“Now we are trying to get a good framework for the plants,” he said.
Matt Gitzendanner, an associate scientist and collection manager in Soltis’ lab, is working on a computer model of the flowering plant section of the Tree of Life — only 1,900 species, or 1 percent of the tree. Each line represents an individual organism that has had its DNA sequenced. Where lines converge is where species connect with a common ancestor.
“That’s just a start,” Soltis said.
They have DNA data on less than 10 percent of the plants, he said.
“We have a long way to go to understand life on Earth.”