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David Reznick

Distinguished Professor of Biology
David Reznick
Exploring Climate Change and Evolution
When we think of evolution, we often think in past tense, of how the world evolved to become what it is today. Biologist David Reznick’s studies on guppies have fundamentally changed our understanding of evolution, proving that evolution is a contemporary reality and that the world and all the organisms in it are changing quickly all around us.

Areas of Expertise

Select Honors and Distinctions

  • American Academy of Arts and Sciences (2011)
  • E. O. Wilson Naturalist Award (2003)
  • Fellow of the American Association for the Advancement of Science (2000)
  • UC Riverside Faculty Research Lecturer (1999)
  • Author of “The Origin Then and Now: An interpretive guide to the Origin of Species”


Q: What is the goal of your research?
To understand the process of evolution, how evolution works and how it interacts with ecology.

Q: Why is your research important?
When I began to do my work, people often commented that they hoped I’d live long enough to see organisms evolve. Mostly, we’d understood evolution to be a historical process and we didn’t think of it as an experimental process. My research shows that evolution is fast and we can see consequences of evolution in as little as one to two years in certain organisms. Now, there’s a paradigm shift: it’s old news that evolution is contemporary, and it is quick. I think my work has helped to contribute to that knowledge.

Q: What has been learned from your research in Trinidad?
I look at evolution in natural populations of guppies in Trinidad where rivers are punctuated by waterfalls, which stop predators but not guppies. Without predators, we found guppies become very common and change the structure of their ecosystem. Many of the ways they evolve are not a direct consequence of not being killed; they’re an indirect consequence of an overabundance of guppy populations.

Q: How is your research used?
Practically, humans cause commercially exploited fish to evolve. People were inspired to think about commercial fisheries in part due to my results on guppies. They knew that predators affect how guppies mature, how quickly they grow, how big they are when they have babies and how many they have, and made the connection that humans are predators catching and eating the big adults. My work can be used to help understand what the consequences to these populations might be and how to better regulate the practices.

Q: How does climate change affect evolution?
Organisms are evolving and changing as the world around them changes. Climate change alters the composition of communities so species found together will change, causing animals and plants to evolve. When climate changes, organisms have two options: change and accommodate, or go extinct, and those that survive may be very different from what they were before.

Q: What’s next for your research?
We’re using an integration of genetics and statistical theories to look at evolution—when it happens, why it happens, how fast it happens and what the individual attributes are that make it happen. We’ve been working on individually marked fish and we keep a few scales for genotyping so we can learn from individuals and how successful they are to contributing to offspring of the next generations.

Q: Why is UCR a great place to do research?
UCR is for me a lifestyle—it isn’t just the research that I do, but it’s also home for me. I live on the edge of the Mohave Desert where I can walk or ride my bike to work and I have access to thousands of acres of open land. The attraction to Riverside is not just as an inspiring place to do research, but also to live.

Q: What does “Living the Promise” mean to you?
One of the promises of university education is upward mobility. Riverside is a place where this is happening in a way that exceeds almost every other university and we’ve got one of the most diverse student bodies. UCR is affordable and at the same time, we’re a first-class research university, located in a place where we can cater to a diverse community of students. UCR is a doorway to upward mobility, the promise of a better future.

David Reznick “People think of the world as stable—that everything you see today will be the same tomorrow. Evolution means that everything is changing. We must constantly accommodate the change in the world around us.”

—David Reznick
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