image: The Puerto Rican Oriole is on the species evolutionary biologist Kevin Omland studies. His work has challenged conventional wisdom about evolution, and his new book, Understanding the Tree of Life, calls on decades of research and teaching to dismantle outdated views that place humans at the pinnacle of evolution or label certain species as "primitive." Instead, the book emphasizes shared traits alongside unique adaptations, using engaging examples from research on genomes, fossils, and animal behavior.
Credit: Ryan Mandelbaum
In a world where evolutionary biology often gets boiled down to simplistic hierarchies of "primitive" and "advanced" species, a new book by University of Maryland, Baltimore County (UMBC) biologist Kevin Omland offers a fresh, genomics-informed perspective. Understanding the Tree of Life, published by Cambridge University Press as part of its "Understanding Life" series, invites readers to rethink evolution as a continuous, branching process where all organisms—from humans to platypuses to bacteria—are interconnected cousins sharing a common ancestry.
Omland draws on decades of research and teaching to dismantle outdated views that place humans at the pinnacle of evolution or label certain species as "primitive." Instead, the book emphasizes shared traits alongside unique adaptations, using engaging examples from research on genomes, fossils, and animal behavior. It covers topics like speciation, the diversity of life, and different types of phylogenetic trees, making complex ideas accessible without sacrificing accuracy.
"This book is about shaking up how we think about evolution," Omland explains. "We often hear that humans are a 'recent arrival' or that sharks and crocodiles are 'ancient,' but that's misleading. Every lineage has been evolving for the same amount of time since their last common ancestor. Genomics shows us that evolution is ongoing in every species—processes like mutation and natural selection are constantly at work."
No species is superior
The inspiration for Understanding the Tree of Life stems from Omland's 25 years teaching introductory biology at UMBC, where he's witnessed bright students grapple with counterintuitive concepts. "I've had countless classroom interactions that revealed misconceptions, like viewing species on a ladder from lower to higher," Omland says. "This book builds on those conversations to help readers see that there are no primitive organisms—every one is a mix of ancient inheritances and recent innovations tailored to its niche."
One standout example Omland highlights is the platypus, often dismissed as primitive because it lays eggs. Yet, as he describes, it boasts recent adaptations like electroreceptors in its bill for hunting in murky waters and venomous spurs for defense. "We judge from a human perspective—our vision is great, but can we sense prey buried in mud? The platypus can," Omland notes. Such stories underscore the book's core message: Evolution doesn’t have a destination; it's a complex history of gains and losses, with no species superior to another.
Omland's research on bird plumage and song evolution informs this view, showing how traits appear and disappear across lineages. A 2014 landmark paper from his research group found that female birdsong was present in the common ancestor of all songbirds. Counter to long-term assumptions, the authors found that many temperate lineages have recently lost female song. As another example of trait disappearance, tetrapods gained legs, only for some of their descendants—like snakes and whales—to lose them. This challenges dictionary definitions of evolution as a mere accumulation of complexity, urging a more nuanced understanding rooted in modern science.
We’re all cousins
The book also carries a broader humanistic appeal, beginning and ending with the idea of universal relationship. "We're all cousins—not just with other humans, but with every organism on Earth," Omland says. "My most distant human relative shares an ancestor with me from about 200,000 years ago, but we're cousins with trees and bacteria too, tracing back billions of years. On this small planet, we should treat all our cousins with care."
Fellow researchers praise the book's clarity and impact. "In this fascinating book, Kevin Omland takes us on a tour of the tree of life, intertwining marvelous stories of evolutionary adaptation with cogent explanations of how scientists discover what we know about the history of life," says Jonathan Losos, acclaimed author and William H. Danforth Distinguished University Professor at Washington University in St. Louis.
David A. Baum, professor of botany at the University of Wisconsin–Madison, adds, "Omland identifies and debunks significant misinterpretations about evolutionary history that are widespread inside and outside of professional scientific circles.”
Stacey D. Smith, associate professor of ecology and evolutionary biology at the University of Colorado Boulder, echoes Baum. “Omland strips away all of the misconceptions about phylogenetic trees and our own evolutionary history,” she says, “so that we can see the fundamental beauty in the continuously unfolding story of life on this planet.”
Aimed at nature enthusiasts, students, and practicing scientists, Understanding the Tree of Life promises to transform how readers view biodiversity and humanity's role in it. The book is available now from Cambridge University Press, major retailers, and local bookstores around the world.