Lisa Powers for redOrbit.com – Your Universe Online
Scientists have known for years that birds breathe differently from mammals, exhibiting a unidirectional airflow in their lungs. This was thought to occur only in the class Aves (birds), and scientists hypothesized it was due to the high energy demand required for flying.
But science is a dynamic process and thanks to new research, which has found that iguanas also breathe in a unidirectional manner, we are reminded of just how similar birds and reptiles actually are.
Published in the Proceedings of the National Academy of Science, the study was performed by Colleen Farmer and her colleagues at the University of Utah—following on the heels of several other reptile studies produced by the team. In 2010, they also determined that alligators exhibited a unidirectional air flow.
The findings of the 2010 study inspired Farmer and her colleagues to investigate airflow in other groups of reptiles. While alligators are reptiles, they are not lizards. Instead, they belong to the group classified as crocodilians. First focusing on monitors, a primitive and ancient lineage of lizards, they found the same airflow pattern as in the crocodilians.
Sometimes different groups of animals develop similar structures, features or characteristics because of pressures from the environment. This is called convergent evolution. But sometimes, the code is already programmed into the genes and passed down from the ancestors. In examining the two different reptiles (crocodiles and monitors) and comparing them with birds, this was the big question: Were these similarities in breathing pattern convergent evolution, or simply a genetic trait passed down from a common ancestor?
Scientific evidence shows the first reptiles appeared around 300 million years ago. Dinosaurs evolved over the next 120 million years and then were mostly wiped out during the Cretaceous–Paleogene (K–Pg) extinction event around 65 million years ago, except for a few feathered dinosaurs that have evolved into our present day birds. In a 1998 paper published in Nature, the authors noted, “The fossils of two new species of dinosaur have been discovered in China – dinosaurs with feathers. These creatures effectively close the debate on whether or not birds and dinosaurs share a close evolutionary heritage. The answer is a resounding ‘yes’.”
While we’re excited this new research adds to the growing reptiles-and-birds-descended-from-a-common-ancestor evidence, we’ve been convinced of this for like two decades now, and wonder where the rest of the science world has been. Did they not see Jurassic Park?
(We kid; we kid…kinda)
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