Alice Roberts - The Incredible Unlikeliness of Being: Evolution and the Making of Us

PRAISE FOR THE INCREDIBLE UNLIKELINESS OF BEING

Alice Robertss engagingly personal style connects you (she uses the second person pronoun advisedly) to your ancestors, to your own personal beginnings as a single cell and, in a most attractive way, to herself as an author of great charm. From your brain to your fingertips, you emerge from her book entertained and with a deeper understanding of yourself.

Richard Dawkins, evolutionary biologist and author of The Selfish Gene

Witty, personal, and above all informed by passion and deep knowledge, this is the story of you, not just from conception onward but from the millions of years of evolution that have shaped the way we are today. It effortlessly fuses what we know about how you develop as an embryo with how our species came to be. Bones, genes, sex, and evolution, all life is in these pages. Alice Roberts is our preeminent science story teller.

Adam Rutherford, geneticist, broadcaster, and author of Creation

A brilliant account of how a single cell transforms itself into a living, breathing, thinking person. The book exudes physicality. It is like having an intellectual massage of every muscle in your bodyafterward you are keenly aware of your body and feel like a different person.

Mark Miodownik, materials scientist and broadcaster (The Genius of Invention)

The biggest gap in biology is that between DNA (which is just chemistry) and living creatures. Somewhere, the answer must reside in the embryo, and in this book Alice Roberts has set out to find it. With wit and enthusiasm, she succeeds.

Steve Jones, geneticist and author of The Single Helix

Alice Roberts is an anatomist and anthropologist, television presenter, author and professor of Public Engagement with Science at the University of Birmingham. She has presented Coast, Horizon, and several series about human evolutionincluding, The Incredible Human Journey, Origins of Us, and Prehistoric Autopsyon BBC2.

She has also presented Inside Science on Radio 4, and she writes a regular science column for The Observer. She lives near Bristol with her husband and two small children.

ALSO BY ALICE ROBERTS

Evolution: The Human Story

The Incredible Human Journey

The Complete Human Body

Dont Die Young: An Anatomists Guide to Organs and Your Health

New York London

2014 by Alice Roberts

Cover design by Two Associates

First published in the United States by Quercus in 2015

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e-ISBN: 978-1-62365-808-3

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In loving memory of Pam Stevens

Ex ovo Omnia

(Everything comes from an egg)

WILLIAM HARVEY (1651)

T he way I look at the world, and my concept of myself in time and space, has been completely transformed by becoming a mother. I gave birth to my first baby in 2010, and at that precise moment, I had an incredible, almost mystical, feeling of being connectedconnected with my own ancestors, and connected with my descendants. I felt more than an individual: I was a link in a chain of life. For me, it was a very female thing. I was giving birth to a daughter, just as I had come from my mother, and she from her mother, and back and back in time.

If youre a man reading this, while you may not be able to give birth you could reflect in a similar way about your Y chromosome, which connects you to a lineage of male ancestors. Admittedly, it might not feel quite as epic, but then theres nothing like childbirth to make a thought seem momentous.

As an expectant mom in a twenty-first-century developed country, I had the incredible opportunity to see each of my babies before they were born. I remember the soaring joy I felt, just twelve weeks into my pregnancy, when I saw my tiny daughter for the first time, floating in her own small pond of amniotic fluid. At that point, I didnt even know she was a girl. It was wonderful to see her, but there was still a great gulf between that image on the screen and the experience of being pregnant.

Im an anatomistits my business to know the structure of the human body and how it developsbut however much I knew about the development of an embryo, it didnt lessen that feeling that what was taking place inside me was utterly miraculous. Fertilization is incredible in itself, and then the idea of a fertilized human egg, a single cell, transforming into something as complex as a complete human being is astonishing. By the time of my twelve-week scan, so much of the fetus had already been formed: it already had arms and legs, fingers and toes, guts and a beating heart. Already, it looked like a miniature baby. How did it get there, from just one cell at the moment of conception?

Theres so much unlikeliness in you being here, right now, reading this. Theres the unlikeliness of your parents meeting each other. There would have been so many points when their lives could have turned out differently, when each of them could have met someone else. Once they had hooked up, theres the unlikeliness of that ONE egg meeting that ONE sperm that made you. But I think that this unsettling feeling of the unlikeliness of being goes even further.

The development of a fertilized egg, a single cell, into a whole human being seems to defy belief. It appears to be some kind of biological miracle. But its a miracle that doesnt require you to believe in any supernatural or divine intervention; its a natural miracle, and over the last few centuries, scientists have unraveled many of the secrets of this incredible transformation (although there are certainly some secrets left to be discovered). At first glance, the development of a single egg into a whole person seems like such an impossible feat, such an unlikely occurrence, that we need to imagine some kind of supernatural guiding hand for this to happen, but when we understand the process in more detail, we can see how molecules, cells, and tissues can build themselves into the organs of our bodies. Its a fundamental process that unites us with every other animal on the planet.

When you think about your own beginning, its almost impossible to believe that you were once just a single cell: a fertilized egg, but you know that this is true. It may seem unlikely, but your very existence proves that it happened. You might also find it hard to believe that you could be descended from ancestors who, long ago, were also just single cells. But once youve come to terms with the undeniable fact that you yourself developed from a single cell during your embryonic development, perhaps its easier to believe that you, that