Most of us lead pretty sedentary lives but do you know that you are a natural-born runner? Endurance running was of primary importance to our ancestors that provided them with a way of surviving in a changing landscape to find an important source of energy and protein: meat.This evolutionary change did not happen overnight. In fact, from your brain to your foot, the journey that began with a single cell after the sperm-ova encounter in your mother's womb is such a fascinating one that once explored, it will sure leave you spellbound.
"Human adaptation to running suggests that profound changes in the body can occur before genetic changes take place," writes Alice Roberts, an anatomist and professor of public engagement in science at the University of Birmingham.Her book uncovers the evolutionary history hidden in all of us - in you as you read this while trillions of nerve cells in your brain function as a team to help you intercept the hidden message."Look at your hand and see not only something which developed out of a minute limb in a developing embryo but something that evolved from a fish's fin over millions and millions of generations," explains Robert who, after birth of her first baby in 2010, immediately felt "connected" to her ancestors.
The presenter of BBC's famous "The Incredible Human Journey" television series, Roberts gives us a fresh look at our own bodies, allowing us to understand how we develop as an embryo, from a single egg into a complex body, and how our embryos contain echoes of our evolutionary past."There is so much unlikeliness of your being here, right now. There is the unlikeliness of your parents meeting each others. Once they hooked up, there was the unlikeliness of that ONE egg meeting that ONE sperm which made you," she comments.At first glance, the development of a single egg into a whole person seems 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," she notes.So it is not just a sperm and an egg that made you. There is a whole lot of people involved - from our earlier ancestors like worms and fish to our closest living ape cousins - that made you happen.Today, "we create wonderful things, including art, music and literature, as well as technology which improves our chances of survival, reproduction and longevity," she elaborates.But we are not going to live forever. We might have slowed evolution down a bit, in developed countries, at least. But even in such privileged places, there will be differences in how many children couples have, and those differences will change the frequency of genes in the population.
"Slowly, perhaps, but it is still evolution," she adds."We survived the asteroid impact nearly 66 million years ago that wiped out dinosaurs. Now, we won't grow extra, fully functioning fingers or toes. We won't grow wings or extra legs. We won't grow furry again.It is hard to predict where our evolutionary destiny lies as it would have been to predict, 66 million years ago, that some of the mammals who hid from the dinosaurs would have evolved into monkeys, that some of those would have evolved into apes, and that some apes would have become humans."For me, well, I feel extraordinarily lucky to be here. Just imagine, for a moment, how easy it would have been not to be there," she ponders.
As an individual, the chances of your conception are vanishingly small. It is estimated that around half of conceptions are lost, many before they are even noticed.Of those unsuccessful pregnancies, it is estimated that half involve major chromosomal abnormalities. Miscarriages work as a natural screening programme.It is not that parents often talk about but it does illustrate again the extreme unlikeliness of your own being."Accepting our place within the natural world, not outside it, surely means that we must shoulder the responsibility and work toward a sustainable future, for ourselves and for other species on the planet," she concludes.After reading this book, you may get a sense of being a real important key in the chain of events as they unfolded over millions of years on Earth.