The study of Charles Darwin is a useful exercise in the history of science, as it teaches us that the library of ideas associated with evolutionary thinking (for example, natural selection and descent with modification) were developed from a suite of concepts from across multiple disciplines, and involved deep reflections and debates around the connection between science and society.
In the century-and-a-half plus since “On the Origin of Species” was first published, the role of the scientist as public educator has mostly disappeared from the list of tasks formally associated with leading scholars. In the opinion of some, the opposite sensibility — that science is for scientists, and public engagement is for someone else, mainly journalists or teachers — has surreptitiously ossified into the status quo.
In “Explaining Life Through Evolution,” award-winning evolutionary biologist Prosanta Chakrabarty — a TED senior fellow, a professor at Louisiana State University, and the curator of fishes at LSU’s Museum of Natural History — seeks a return to the days of Darwin, where the authors of cutting-edge science took on the role of public educator. In the process, he generates a courageous text that achieves a task that is curiously rare: explaining what evolution is, how it works, and why it is more important to understand today than at any point in our history. Most importantly, the target audience is one mostly ignored by eminent thinkers in the basic sciences: everyone.
The book’s style and structure are chimeric: a sequence of chapters organized like a college textbook, mixed with visuals, interludes, and intermittent social commentary.
It is divided into four parts, each with several chapters. Part I describes the author’s personal perspectives and motivations, and Part IV the connection between evolutionary understanding and the scientific and political zeitgeist. It’s in the middle two parts where the bulk of the education lives. In Part II, Chakrabarty walks the reader through the birth of evolutionary reasoning, and the various subtopics related to evolutionary biology: the historical underpinnings, and the nuances of Darwinian thought, Mendelian genetics, and other pillars. Part III covers a range of concepts that are often misunderstood.
The book even offers a creative interlude: a mini-graphic novel that explains the history of Darwin’s ideas. This is a wise strategic choice. Unlike the technical details, history is hard to visualize, and can be difficult to summarize in an engaging manner.
By using the illustrated approach, Chakrabarty sacrifices little rigor in explaining the large cast of characters (Darwin, Robert FitzRoy, George Lyell, and Alfred Russel Wallace, among others), and the drama that enveloped the birth of evolutionary biology. With this sleight-of-hand, Chakrabarty reveals that science is a human endeavor, where emotions like fear, depression, and insecurity play a central role. This is an underappreciated element in public understanding of the scientific process, one that is often ignored or de-emphasized in education.
From the technical side, the chapter in Part II titled “Mutants and Mutations” does an impressive job of explaining the different sorts of mutation, how they happen, and how they generate the variation that is the fuel for biological innovation. But the strength of the book is not only in how it walks the reader through complicated terrain, but in how it successfully links these processes to those presented in other chapters.
In the case of mutations, the relevance is linked to the chapter that follows, “Speciation: The Formation of New Species.” This area is close to one of the focuses of Chakrabarty’s research: how we organize biodiversity into categories. His expertise is on full display in how he deconstructs the idea of speciation, which remains one of the most challenging concepts to teach in all of biology. “Small evolutionary changes (ones that result in the small differences between species or populations that occur in shorter periods of time) represent what biologists call ‘microevolution,’’’ he helpfully explains. “These small differences accumulate, leading to bigger evolutionary differences that we call ‘macroevolution,’ such as the evolution of flowering plants and associated insects.”
Such topics are handled extraordinarily well, which is the source of my only criticism: that Chakrabarty could have taken the reader on a ride through more complicated concepts, such as the modern evolutionary synthesis and the microbiome (which is mentioned in passing). The former describes an early-to-mid 20th century consilience between Darwinian evolution and Mendelian genetics in the langauge of mathematics and statistics. The latter describes the several-decades quest to understand the trillions of microbes that often live in communities, inside of, or contiguous with, larger organisms. Few are up to the task of explaining these concepts to the lay person (or lay scientist). But the author’s clarifying lens could have just as easily explained these and many other salient ideas.
There are, however, good reasons to not include these details: The book aims to describe the fundamentals of evolutionary biology, in a manner that is truly digestible to the novice. Chakrabarty stays true to this goal, which must have led to the difficult (and appropriate) decision to leave lots of good stuff on the cutting-room floor.
The third part, titled “Questions and Misconceptions,” offers perspectives on current scientific issues, wrapped in a compelling bundle of short chapters that cover topics ranging from the the origin of life to why evolution does not always optimize.
He discusses how evolution can be imperfect, generating observable traits that are troublesome, even in otherwise successful organisms. To accomplish this, he compares the flawed anatomy of human beings to that of a fish. “When all is said and done, I’d rather have the fishy body of a crappie than the crappy body of a human.”
In other words, while many aspects of human biology may appear impressive, there are aspects that are poorly constructed and prone to failure, often manifesting as injury and illness.
It’s a critical insight for readers who might be enamored with the powers of evolution, and erroneously think that humans are the pinnacle of evolution. This is one of biology’s greatest misconceptions, one that Chakrabarty persuasively yet gently disabuses us of multiple times.
For all of his impressive engagement with a large swath of concepts in evolutionary biology, the transcendent magic of the text lives in its bookends.
Chakrabarty opens with several chapters describing his own experiences as a teacher of evolution in an unfriendly political climate, and how these experiences have inspired him. This isn’t the narcissistic chest-thumping of an expert shouting about why they are right, but rather a thoughtful and transparent articulation of the power of evolutionary reasoning, and his mission to make it legible to the world.
In a sense, the book’s closing chapters form a sequel to the introduction, boldly taking on modern controversies with care: the Anthropocene, sex and gender, creationism, and a post-truth world. By this time, the author has earned the reader’s trust, and we are equipped to understand the connection between the particulars of evolutionary theory and its real-world significance. This is a tall task, but it fortifies the book as a comprehensive yet relatable treatise on all aspects of evolution.
Evolutionary biology is a field where popular books written for the public are not uncommon. In fact, many large debates about evolution — the tree of life, sociobiology, sexual selection, and others — have played out in the pages of books popular enough to show up in airports.
Some of them — like Ernst Mayr’s “What Evolution Is” or Jerry Coyne’s “Why Evolution is True” — certainly succeed in explaining evolution, but also serve as vehicles for the authors’ original ideas. These are strengths of these texts, which serve as dialectics aimed at capturing more elaborate debates surrounding evolution.
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The triumph of “Explaining Life Through Evolution,” however, is in how the author tempers these urges, and focuses on teaching the public the basic structure of evolutionary reasoning. Yet the book isn’t soulless: It is written in a voice somewhere between your smartest professor and your coolest friend. And Chakrabarty emphasizes that though he aims to teach the ideas first, he is also a person with a story, and multiple influences.
Having been a teacher in settings ranging from correctional facilities to middle schools and undergraduate classrooms, I can affirm that this is one of the few evolution books that could truly be taught anywhere (“Evolution: The Triumph Of An Idea” by Carl Zimmer being another). Chakrabarty also reminds us why his endeavor is important, and how we can win the war against science in the face of climate change, the rise of misinformation, and the return of race pseudoscience.
He does so by striking the necessary balance between confidence in his knowledge, and a modest understanding of his place in the world. “I don’t know how to keep an economy going or how to run a business and that not all the answers to our most pressing environmental problems can come from science,” he writes, “but scientists can warn us about the future consequences of our actions.”
C. Brandon Ogbunu is an assistant professor in the Department of Ecology and Evolutionary Biology at Yale University, and is an external professor at the Santa Fe Institute.