In a matter of 304 pages, author Prosanta Chakrabarty manages to encapsulate the four billion-year history of species visible on the planet. Titled Explaining Life Through Evolution, and published by Allen Lane (an imprint of Penguin Random House India), the book traces the story of evolution, or “the grand process that led to the uninterrupted chains of ancestor-to-descendant relationships that connect all past and present life on earth”.
While earlier books on the topic have tried to spotlight the diversity and differences that make the various species unique, Chakrabarty chooses to focus on common connections instead. In a world divided, his approach makes a lot of sense—he focuses on the fact that most living beings might be closer to each other than we think.
An evolutionary biologist at Louisiana University, US, Chakrabarty has many laurels to his name—he is a senior fellow at TED, a Fulbright distinguished chair, and a fellow of the American Association for the Advancement of Science.
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One can’t help but wonder, why a book on evolution now? Over the past five years, more and more people have been going for ancestry tests—according to a 2019 report in the MIT Technology Review, by the start of that year more than 26 million consumers in the US had added their DNA to four leading commercial ancestry and health databases to find out more about their family history and secrets.
In such a scenario, it is imperative to truly understand what these results mean scientifically and socially. “He (the author) thinks we should be celebrating the fact that our diversity comes from the same little drops of water and sunlight, each of us just shining a little differently as seen through the prism of evolution,” states the publisher’s note.
In a way, the book is also a personal quest for Chakrabarty to try and understand what it means to be truly Indian. Born and raised in the US, he has known India only as the place of his ancestors. There is a disconnect somewhere. For while his memories and lived experiences are all in the US, to other Americans his features and markers represent everything Indian. At some level, then, he is trying to understand what it means to be Indian in the biological sense.
The strength of Explaining Life Through Evolution lies in the fact that it makes a complex subject like evolution so accessible. Keeping the language simple, almost story-like, Chakrabarty has made concepts of mutation and natural selection easy to understand. For a layperson like me, who is just starting to delve deep into evolutionary biology, this book is a must-read. It is populated with boxes, diagrams and illustrations to act as a guide to evolution. There is even an illustrated plot of a movie on Charles Darwin by the famed artist Ethan Kocak, based on Chakrabarty’s script of sorts (can this be turned into an actual movie please!).
Chakrabarty has not shied away from mentioning voices that contradict his point of view. Take, for instance, Jordan B. Peterson, who wrote the book 12 Rules for Life, arguing that human sexuality and gender are essentially fixed, as distinct sexes were invented millions of years ago. Instead of dismissing such arguments outright, Chakrabarty explains why such a line of thinking might not work.
The most interesting sections dwell on the misconceptions about evolution and race, sexuality, gender and religion.The way Chakrabarty connects social constructs and everyday life with evolutionary principles is what makes this book so pertinent in today’s times. The first chapter itself takes this head on. Chakrabarty writes about moving to Louisiana just when the Louisiana Science Education Act had been passed with the backing of the then governor, Bobby Jindal. This allowed schools there to teach the Biblical account of creation in science classes as an alternative to evolution.
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It was not just in parts of the US that the anti-evolution stance was taking hold—in several other countries too, evolution studies are being erased from the education system or being taught within a religious framework.
Chakrabarty discusses in detail the problems of combining religion and science. “Science is about observing and testing natural phenomena in order to give a reasoned, evidence-based explanation for those events. Religion, on the other hand, can provide answers to questions science doesn’t cover (e.g., what is the meaning of life?). But it can also provide answers that can’t always be tested.”
He illustrates this with an example. If someone believes God makes apples drop to the ground, a scientist like Chakrabarty cannot prove it false, for he can’t test it. “There isn’t room for questioning things or scientific inquiry if you believe flatly that ‘God controls everything that happens’,” he writes.
In the chapter Our Genealogy And Ancestry, he explains that race is a social construct rather than a biological one. Chakrabarty argues that we are blended shades in a tub of mixed paint, in which you can see streaks of black, white, brown, and every other colour, “but it’s all made of the same stuff”.
So, why does one need racial categories at all? “...to defend people from historically marginalized groups,” he writes. Take, for instance, the African-Americans who were enslaved and deprived of civil rights. It is for these “historically underrepresented categories” that social categories are required. Even when talking about equality, Chakrabarty keeps race within the social ambit, not the biological one. “Just because races don’t exist in an evolutionary sense doesn’t mean there isn’t racism,” he writes.
A section on the Tree of Life offers considerable food for thought. Chakrabarty urges readers to look beyond the linear view of evolution, such as the one offered by Aristotle’s “Ladder of Life”, which shows bacteria and plants at the bottom, as primitive. In this view, progression takes place in a straight line, from fish and amphibians to reptiles and mammals and then humans. This, in effect, portrays humans as the most evolved on the ladder—an embodiment of complexity.
Chakrabarty, however, believes evolution is not a static thing, nor is it about supremacy or perfection. Rather, it is like a bursting firecracker, expanding from the centre. “To truly know the answer to where we are from, you need a map. The map is called the Tree of Life…. We can use DNA to build the Tree of Life and show the connections between every organism on Earth including ourselves. Just because we are the only organism that can put together the Tree of Life doesn’t mean that we stand apart from it. We are still a piece of the Tree, and as on a map, we can use it to see where we are and where we came from,” he writes.
Each chapter, then, seeks to debunk myths. So, for instance, chimpanzees may be our closest living relatives today but in the past there were species we were closer to. In fact, bony fish such as trout, seahorses, donkeys and humans are more closely related to each other than we may imagine. For that matter, one can’t group all sea- and fresh-water fish under a common umbrella. Cartilaginous fish such as sharks and bony fish like goldfish have been evolving independently over time.
“Cartilaginous fishes like sharks have a more common ancestor with each other, and bony fishes are all more closely related to each other than to any other group. In the Book of Life, the cartilaginous fish chapter has fewer species pages than the bony fish chapter, and the bony fish chapter includes not only tuna and tarpon but all land vertebrates, because again all tetrapods descended from a common fish ancestor. Yep—you are a fish my friend (a fish being any vertebrate)....a fish out of water, and that’s why your body is a flop,” writes Chakrabarty.
It’s this kind of ease and humour about life, existence and origin that draws you to the book. It forces you to examine the intolerance to other species and ideas of supremacy—one reason why this book is also an important one. As you turn the pages and soak in Chakrabarty’s arguments, you can’t help but wonder how people reject evolution. Is it because, as the author says, evolution puts us too close to animals? “Who knows, if we blurred the line between us and the rest of the animal kingdom, maybe we would see ourselves for what we are—just another recently evolved branch of the Tree of Life,” he writes.