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Study Suggests that Change in Developmental Timing Was Crucial to Evolutionary Shift from Dinosaurs to Birds

by PhysOrg staff

At first glance, it’s hard to see how a common house sparrow and a Tyrannosaurus Rex might have anything in common. After all, one is a bird that weighs less than an ounce, and the other is a dinosaur that was the size of a school bus and tipped the scales at more than eight tons.

For all their differences, though, scientists now say that two are more closely related than many believed. A new study, led by Harvard scientists, has shown that modern birds are, essentially, living dinosaurs, with skulls that are remarkably similar to those of their juvenile ancestors.

As reported in a May 27 paper in Nature, Arkhat Abzhanov, Associate Professor of Organismic and Evolutionary Biology and Bhart-Anjan Bhullar, a PhD student in Abzhanov laboratory and the first author of the study, found evidence that the evolution of birds is the result of a drastic change in how dinosaurs developed. Rather than take years to reach sexual maturity, as many dinosaurs did, birds sped up the clock – some species take as little as 12 weeks to mature – allowing them to retain the physical characteristics of baby dinosaurs…

(read more: PhysOrg)       (image: Nobu Tamura)

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Provided by Harvard University 

Journal reference: Nature