UF helps map out Tree of Life
Published: Friday, February 8, 2013 at 6:48 p.m.
Last Modified: Friday, February 8, 2013 at 6:48 p.m.
When paleontologist Jonathan Bloch takes walks with his three young children, he often hears the same questions that he asks himself at work: Where do all these animals come from? How did that happen?
Bloch, the associate curator of vertebrate paleontology for the Florida Museum of Natural History and a University of Florida professor, was one of the authors of a major international study published Thursday in the journal Science that goes to the heart of answering the questions of the naturalist in us all.
The results of the six-year Tree of Life study, sponsored by the National Science Foundation, provide the most comprehensive data to date about the genetic and physical traits of the ancestors of placental mammals, a category that includes humans.
Researchers collected anatomical, morphological and genetic data on more than 80 species and entered all of it, replete with pictures, into a huge database called MorphoBank that the public can access at www.morphobank.org
"The most interesting thing for us was that primates are more closely related to the order that is comprised of flying lemurs and tree shrews," said Zachary Randall, a research associate at the Museum and UF graduate student who worked on the study.
Another main finding of the study is that a huge diversification of species occurred right after — and not before — the extinction of dinosaurs 65 million years ago.
"It very robustly shows that the diversification of modern mammals for the first appearance of things like bats, rodents and primates happened just after the extinction of dinosaurs, which is different than other molecular estimates that were much deeper in history," Bloch said.
The researchers looked at more than 4,500 traits, including variations in teeth.
"Finding a tooth is super-easy compared to other parts of the body," Bloch said, adding that because teeth are covered in enamel, they preserve well.
"The neat thing about teeth is they actually tell us a lot: of what the animal is eating, how large the mammal was. They also tell us about relationships," Bloch said. "They are amazingly conservative and retain a lot of their ancestry."
The anatomy of the skull also contains many important parts, Bloch said.
"A lot of what we think about in terms of our identities is processed in our skulls," Bloch said.
Randall said that working on the study was a great way to learn about anatomy.
"You can look at an image of a human and compare that to a primate, and compare primates to non-primates and see how similar they are," he said. "As primates, we all share the commonality of having nails as opposed to claws on our digits. And large brains and forward-facing eyes."
Bloch said that they also studied the post-cranial skeleton, just below the skull, which gives a lot of information about how animals are related to each other and whether they could hop or whether they lived in trees.
Bloch said that working on the study, which brought together many of the world's experts in zoology, paleontology and anatomical sciences, opens the door to future studies.
"I see this as a stepping stone for the next generation," Bloch said. "Even though we might be wrong about many things and included a small amount of species, there will only be progress from now on. We don't have to reinvent the wheel."
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