March 26, 2018

Evolution of Darwin’s Finches: Integrating Behavior, Ecology, and Genetics

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For many, Drs. Rosemary and Peter Grant, evolutionary biology, Princeton University, are living legends in the field of modern evolutionary biology, having conducted over four decades of field research on the Galapagos finches. On Monday, March 12, students, professors and alumni packed into Call Auditorium in Kennedy Hall to witness the scientists bring their research on the Galapagos Finches to life.

Rosemary’s talk, titled “Evolution of Darwin’s Finches: Integrating Behavior, Ecology, and Genetics” kicked off the Paul C. Mundinger Distinguished Lectureship, in honor of the late Paul C. Mundinger. Mundiger received his Ph.D. from Cornell in 1967 and developed a strong attachment with lab of Ornithology as a graduate student. Mundinger, formerly a professor at Queens College, prized teaching and inspiring his students with his love for evolutionary biology. The Mundinger lectureship series was instituted in 2018 to honor his memory and spirit by bringing inspirational and renowned speakers to the University each year.

“I chose this title because Paul’s very innovative research in a number of species of birds really did integrate behavior, ecology, and genetics. This is where Peter and I have followed in the same footsteps as Paul,” Rosemary said “Paul was able to show that song-learning involved an interaction between experience and genetic determancy or observatory, and this is a really innovative piece of work that he and his colleagues did.”

Rosemary began her talk emphasizing fundamental questions that scientists seek to answer regarding biodiversity.

“All of us, in this room, whether we are hiking in the Alpine meadows, traveling in the Amazon jungle, or diving to the depths of the sea are just amazed at the diversity of life on this planet. How is all of this biodiversity generated? How and why do species multiply? How do we even go about studying this process of speciation?” Rosemary said. Rosemary’s enthusiasm for the diversity of life reverberated throughout the course of her talk.

For many, the most fascinating part of Rosemary’s talk was her discussion of the origin of a completely new lineage,which Rosemary and Peter both followed since its inception through the sixth generation.

“Her results were amazing: she witnessed a new species being born right before her own eyes,” Edwin Quaye ’21 said.

In her talk, Rosemary described the chronological progression of how she and her husband, Peter, observed the origin of the new Big Bird lineage. When the couple went to the islands in 1978, there were two distinct species: Geospiza fortis and Geospiza scandens. After the enormous El Niño event of 1983, the hybrids began to survive and G. fortis and G. scandens began to converge on each other. Five years later, G. magnirostris arrived on the island from Española and mated with the species, G. fortis producing multiple hybrid offspring. These offspring then proceeded to interbreed producing a unique hybrid lineage, which the Grants now call the Big Bird lineage.

“In all respects, the new lineage is functioning as a new separate species. Will it die out through inbreeding depression? Will the genetic variation be augmented through genetic exchange?” Rosemary said. Despite these lasting questions Grant emphasized that whether or not this new lineage survives, it still provides incredibly valuable insight into how a new species could arise and either persist or become extinct.

In the concluding remarks of her talk, Rosemary delivered two key messages. First, she highlighted the dynamic nature of environments and populations and emphasized the importance in keeping environments capable of further natural change for a sustainable environment. Second, Rosemary commented on the importance in understanding ecology and evolution even with our rapidly accumulating genomics data.

“[We] live in very exciting times: the genomics data are rapidly accumulating, changes are happening every year, and this can really enhance our field studies. But reciprocally, a reliable interpretation of genetic data really requires a deep understanding of ecology, evolution, and behavior in the natural environment,” Rosemary said.

For students who are currently enrolled in BIOEE 1780: An Introduction to Evolutionary Biology and Diversity, it was exciting to see the one of the quintessential researchers behind the science that they are currently learning about in their class. Many students approached Rosemary and Peter after their talk, buzzing with enthusiasm or requesting autographs on their sketches of the Galapagos finches.

“I feel very excited now, about her research, especially because she performed her research over such a long period of time, and she stayed with it. It motivates me as well to keep pursuing research,” Jasmine Mack ’20 said.

Elizabeth Mundinger, daughter of the late Paul Mundinger, also attended Dr. Grant’s talk and had nothing but praise for Rosemary.

“It’s really exciting because her research is just groundbreaking and it’s really great that I got to be here and hear all about it firsthand,” Mundinger said.

With her incredible persistence and tenacity, in studying in the same ecological system for over 40 years, Rosemary was able to not only witness the origin of a new species but accumulate a bottomless wealth of knowledge that will continue to inspire growth in modern evolutionary biology.