Yale’s Martha Muñoz receives MacArthur ‘genius’ grant

Yale evolutionary biologist Martha Muñoz, whose study of the “brakes and motors” of evolution in reptiles, amphibians, and fishes has yielded novel insights into the effects of behavior and biomechanics on how organisms evolve, has been named a 2024 MacArthur fellow.

Known as the “genius” grant, the fellowship recognizes “extraordinarily talented and creative individuals” with a track record of excellence — working in a range of fields and disciplines — and helps them pursue their own creative, intellectual, and professional inclinations for the betterment of human society. The fellowships are awarded annually by the John D. and Catherine T. MacArthur Foundation.

Also part of this year’s group of 25 recipients is Dorothy Roberts ’77, a legal scholar and public policy researcher who through her work has exposed racial inequities embedded within health and social service systems.

Each recipient receives an $800,000 stipend over five years which they can spend however they wish. They are nominated anonymously by leaders in their respective fields and are evaluated by an anonymous selection committee. Muñoz, assistant professor of ecology and evolutionary biology in Yale’s Faculty of Arts and Sciences and assistant curator of Vertebrate Zoology in the Yale Peabody Museum, is the 21^st recipient who was actively serving as a Yale faculty or staff member at the time of their award.

Her work investigating the factors that influence rates and patterns of evolution — i.e., its brakes and motors — is reshaping our understanding of evolutionary determinants and providing critical insights into how changing environments and the day-to-day behavior of organisms impact long-term patterns of evolution, the foundation stated. 

“Dr. Muñoz is an integrative evolutionary biologist whose research focuses on the ‘pacemakers’ of evolution, the factors that speed evolution up, and those that slow it down,” said Professor David Vasseur, chair of Yale’s Department of Ecology & Evolutionary Biology. “Her work is essential for understanding how evolution has shaped the lineages of contemporary species and for predicting how they will respond to future environmental changes.

“This award solidifies Dr. Muñoz as one of the very best evolutionary biologists of her generation.”

In her research, Muñoz integrates behavioral observation in natural habitats and lab-based environments; analysis of morphological, physiological, and biomechanical traits; and phylogenetics to explore why some organisms and traits evolve rapidly while others remain unchanged for millennia.

Her study of tropical anole lizards challenged the assumption that environmental pressures are the primary drivers of evolution. She showed that anole lizard species living in warm, sea-level habitats are not physiologically different from those living on colder mountaintops, meaning the lizards inhabiting the mountains did not develop different bodily functions than their warm-weather counterparts to tolerate the colder habitat.

She discovered that behavioral differences enable both the mountaintop and sea-level lizards to thermoregulate in different habitats. The mountaintop lizards get warm by basking on boulders, and the sea-level lizards stay cool by sheltering from the sun in moist vegetation.

“These animals are not passive vessels at the whim of their environment,” Muñoz has said of her work concerning the lizards. “They are endowed with the ability to build their own evolutionary trajectories.”

Muñoz, an assistant curator in the Division of Vertebrate Zoology at the Yale Peabody Museum, also determined that while mountain lizards’ physiological evolution was slowed by their behavior, their body structure evolved rapidly. They developed shorter hind legs and flatter skulls, which enable them to hide from predators in rock crevices. Muñoz expanded on this work to examine adaptive radiation — rapid diversification into new species — among the anole lizards on Caribbean islands.

Phylogenetic analysis showed that it was not the island environment that enabled diversification but rather a functional innovation: adhesive toe pads that allowed the lizards to spread to new niche environments.

In another line of research, Muñoz, who joined Yale’s faculty in 2019, demonstrated that biomechanical principles can also shape rates of evolution. She found that the jointed raptorial appendage (or forelimb) of the mantis shrimp does not evolve as one integrated system. The smallest component, or link, in the appendage evolves more rapidly than the others, and minute changes in its length have a disproportionately large effect on the force of the shrimp’s claw, which it uses to punch or stab prey.

Her analysis of similar jointed systems in the jaws of more than 100 fish species showed that the rates of evolution of the jaw components are controlled by whether the species needs more bite force or bite speed to catch their prey.

Currently, Muñoz and her lab are working to better understand the role of behavior in evolutionary diversification. The work focuses on dozens of closely related species of plethodontid salamanders — lungless amphibians that breathe through their skin — living in niche microhabitats in the Appalachian Mountains.

Dorothy Roberts, who is the George Weiss University Professor of Law and Sociology and the Raymond Pace and Sadie Tanner Mossell Alexander Professor of Civil Rights at the University of Pennsylvania, has done pathbreaking work in law and public policy focused on critical social justice issues, including reproductive health, bioethics, and child welfare. In her work, the foundation wrote, “she sheds light on systemic inequities, amplifies the voices of those directly affected, and boldly calls for wholesale transformation of existing systems.”

Her early scholarship focused on Black women’s reproductive rights and their fight for reproductive justice. In her 1997 book “Killing the Black Body: Race, Reproduction, and the Meaning of Liberty,” she analyzed the historical and contemporary policies and practices that have denied agency to Black women and sought to control their childbearing, and advocated for an expanded understanding of reproductive freedom, the foundation noted. This work prompted her to examine the treatment of children of color in the U.S. child welfare system.

Her 2022 book “Torn Apart: How the Child Welfare System Destroys Black Families — and How Abolition Can Build a Safer World” traced the historical, cultural, and political forces driving the racial and class imbalance in child welfare interventions.

“By uncovering the complex forces underlying social systems and institutions, and uplifting the experiences of people caught up in them, Roberts creates opportunities to imagine and build more equitable and responsive ways to ensure child and family safety,” the foundation wrote.