Evolutionary trees like the one Charles Darwin scribbled to illustrate his epiphany are still used today to help biologists understand and communicate the diversity of life. Like Darwin and his contemporaries, today’s evolutionary biologists are part of an ongoing effort to figure out how Earth's many species are related. As new tools help biologists to analyze evolutionary relationships, the tree of life changes and grows ever more complex.

How will biologists today and in the future to organize all of this information? No one knows for sure - but a number of computer scientists and software designers are taking a crack at it! In collaboration with biologists designers are creating programs that will allow researchers to share and search through enormous amounts of taxonomical information. Some programs, like UC Davis's paloverde, take cues from familiar web tools like WIkipedia and Google Earth, allowing users to search the tree of life from various perspectives and distances.

Beyond making research more accessible to scientists and the public, software tools like this will help scientists around the world work together in new ways - developing new medicines to treat constantly evolving diseases, new products and processes that take into account changing ecosystems, and to understand biodiversity on a local and global scale.

The potential of these tools is as big as the imagination of the designers and engineers behind them - what kind of tool would you create to help organize the tree of life?

Tags : Charles Darwin, technology, visualization, computer science, tree of life, evolution

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Conolophus rosada: Research scientist Gabriele Gentile holding the elusive pink iguana.
Courtesy Photograph settings by Gabriele Gentile, photo shot by an assistantA pink lizard that eluded Charles Darwin when he visited the Galapagos Islands nearly 175 years ago has been recognized as a new species of land iguana. Conolophus rosada is found only in the region of Volcan Wolf volcano on the island of Isabela.

"That Darwin might have missed this form is not surprising, because he stayed in the Galápagos only five weeks, and he did not visit Volcan Wolf [volcano], which to our knowledge is the only place on the archipelago where the pink form occurs," said lead researcher Gabriele Gentile of the University Tor Vergata in Rome, Italy. "What is surprising is that several other scientists visited in the last century Volcan Wolf and missed this form."

Two genera of iguana populate the Galapagos – land iguanas (Conolophus) and marine iguanas (Amblyrhynchus). The two branches split off from a common ancestor about 8-10 million years ago while still on the mainland. The pink iguana, which branched off the Colonophus line, can reach a length of more than 3 feet, and weigh up to 15 pounds. Park rangers first stumbled upon it in 1986 but not until now has it been recognized as a new, separate species.

Darwin spent only five weeks exploring the Galapagos when the HMS Beagle stopped at the archipelago to gather food for the voyage back to England. He investigated the island of Isabela but not around the Volcan Wolf volcano, the only area where rosada has been found. Overall, the naturalist wasn’t too impressed by the land iguanas he encountered on the Galapagos, He described them as “ugly animals, of a yellowish orange beneath, and of a brownish-red color above: from their low facial angle they have a singularly stupid appearance."

Good looks aside, the pink iguana presents other problems for modern scientists. Recent genetic analysis shows the rosada species diverged from other lines of land iguana about 5.7 million years ago. The trouble with that is the island of Isabela is only about one million years old and the oldest extant island in the chain, Espanola, is only 3-4 million years old. That means the split must have taken place somewhere else. But rosada hasn’t been found anywhere else in the Galapagos. How can this be?

One possibility is the split took place on the mainland before iguanas arrived on the islands, possibly floating there on rafts of vegetation. That would have been a long, miserable trip over 600 miles of open water. More likely rosada developed on an earlier island in the chain that no longer exists above sea level. Plate tectonics provide an explanation for this. Ocean crusts spread out from mid-ocean ridges located along the edges of plates moving away from each other. The Galapagos are part of the Nazca plate which is moving east-southeast (at about 7 cm/year) toward the continent of South America. The island chain was created (and is still being created) as the plate moved over a hotspot where a mantle plume is pushing up into the lithosphere and crust. Magma from the plume forms undersea volcanoes that build and sometimes break the ocean’s surface as islands. The Hawaiian Islands were created the same way but on a plate moving in a north-northwest direction.

As it moves toward the South American coastline, the heavier Nazca plate sinks beneath the lighter continental plate in a process called subduction. This means the earliest formed islands in the chain also sink and there is evidence of underwater seamounts between the archipelago and South America. Some of these have been dated to as much as 11 million years old, which means the pink iguanas could have split off from the land iguana line when older, earlier islands were still above sea level.

"This event is one of the oldest events of diversification among species in the Galápagos overall," Gentile said. "The Darwin finches are thought to have differentiated later than the split between the pink and yellow iguana lineages."

Despite rosada's evolutionary ranking, fewer than 100 pink iguanas are known to exist today and the species could be in danger of extinction.

It is, however, fitting that news of the pink iguana comes now. 2009 has been proclaimed the Year of Darwin marking the 200th anniversary of his birth and the 150th anniversary of the publication of his most famous work On the Origin of Species by Means of Natural Selection.

LINKS
Story on LiveScience
Year of Darwin info
Discovery.com story
Geology of the Galapagos Islands

Tags : pink iguana, iguanas, Galapagos Islands, evolution, colors, Charles Darwin

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Charles Darwin, photographed by Julia Margaret Cameron, 1868
Courtesy Julia Margaret CameronI believe I have mentioned this film before - but have you ever seen the documentary "Flock of Dodo's"? It is a well made (imho) film that creatively and sometimes humorously, discusses the evolution vs. intelligent design debate. The thing that I find most interesting about this film is that it shows something that I think is important. While I may think people who support intelligent design or creationism are wrong, many scientists who argue with them act like uppity jerks. Its not likely a debate one side is going to "win" but we can all at least accept that and be civil.

Now, if you want to be ready to argue for evolution, Scientific American has put together a nice little web feature that covers the topics of creationism in the classroom, a state by state breakdown of the creationism in schools controversy, 15 answers to creationist nonsense (again, could be a bit less harsh in the language here) and a discussion about how scientists ought to approach religion and its followers.

Tags : religion, creationism, evolution, Charles Darwin, science

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