It has long been known that diversity of form and function in birds’ specialized beaks is abundant. Charles Darwin famously studied the finches on the Galapagos Islands, tying the morphology (shape) of various species’ beaks to the types of seeds they ate. In 2010, a team of Harvard biologists and applied mathematicians showed that Darwin’s finches all actually shared the same developmental pathways, using the same gene products, controlling just size and curvature, to create 14 very different beaks.
Now, expanding that work to a less closely related group of birds, the Caribbean bullfinches, that same team at Harvard has uncovered something exciting—namely, that the molecular signals that produce those beak shapes show even more variation than is apparent on the surface. Not only can two very different beaks share the same developmental pathway, as in Darwin’s finches, but two very different developmental pathways can produce exactly the same shaped beak.
“Most people assume that there’s this flow of information from genes for development to an inevitable morphology,” says principal investigator Arhat Abzhanov, Associate Professor of Organismic and Evolutionary Biology (OEB). “Those beaks are very highly adaptive in their shapes and sizes, and extremely important for these birds. In Darwin’s finches, even one millimeter of difference in proportion or size can mean life or death during difficult times. But can we look at it from a bioengineering perspective and say that in order to generate the exact same morphological shape, you actually require the same developmental process to build it? Our latest research suggests not.” Via In birds’ development, researchers find diversity by the peck.