And Now for Something Completely Different.
What could the diversity and beauty of plant leaves have in common with one of humankind's greatest creative inventions, the violin? Certainly more than I imagined.
There are many parallels between leaves and violins. Both have beautiful shapes that are potentially functional, change over time, or result from mimicry. Shape is information that can tell us a story. Just as evolutionary changes in leaf shape inform us about mechanisms that ultimately determine plant morphology, the analysis of cultural innovations, such as violins, gives us a glimpse into the historical forces shaping our lives and creativity.
The botanist Dan Chitwood works towards an understanding how leaf shapes are formed and what that means for a plant to grow and thrive. He also studies how leaf shapes change as plant species evolve to adapt in different environments. This work requires morphometric tools that are used to quantify traits of evolutionary significance. Changes in shape over time provide insight into function and evolutionary relationships. A major objective of morphometrics is to statistically test hypotheses about the factors that affect shape. Chitwood is a music lover and one day he asked himself how musical instruments, particularly those designed by masters, evolved over time. Could shapes of violins tell us something about the function of the instrument, or about which violin makers (luthiers) borrowed ideas from others? Could the factors influencing violin evolution be analyzed and understood using the same morphometric approaches used to understand evolution of natural species?
He went on and compiled data on the body shapes of more than 9,000 violins from over 400 years of design history using iconography data from auction houses. The dataset encompasses the most south after violins, and those of historical importance, including violins designed by masters of the trade such as Antonio Stradivari.
His study published in PLoSONE shows that specific shape attributes differentiate the instruments, and these details strongly correlate with historical time. A linear discriminant analysis reveals luthiers who likely copied the outlines of their instruments from others, which historical accounts corroborate. Clustering images of averaged violin shapes places luthiers into four major groups, demonstrating a handful of discrete shapes predominate in most instruments.
Inerstingly, genetics also played a role in the history of violin making. Instrument shapes originating from multi-generational luthier families tend to cluster together, and familial origin is a statistically significant explanatory factor of violin shape. Together, the analysis of four centuries of violin shapes demonstrates not only the influence of history and time leading to the modern violin, but widespread imitation and the transmission of design by human relatedness.
Chitwood concludes: This is a fantastic example of how advances in one field can help advance a seemingly unrelated field. I'll be a happy scientist and musician if by understanding violin evolution this helps lead to improved crop plants that are more productive and sustainable.