Zalasiewicz Jan - Skeletons: The Frame of Life

What links the tumbleweed that has invaded the North American plains, the single outstretched canine tooth of a narwhal, the fourth finger of a pterosaur, the carapace of a beetle, and the ancient submarine mountains, reaching 5 kilometres tall, at the top of which the coral islands of tropical oceans just emerge at the ocean surface? These are all forms of skeleton, produced by living organisms in an extraordinary late flurry of evolution on a planet that was already easing into middle age.

Imagine, then, a world where skeletons had not evolved. We would not see birds flying through the air to perch on a tree branch, or a cat leaping high onto a garden wall (perhaps to try to catch one of those birds), or a crab scuttling on a beach, or a child running through a playground. We might be forgiven for thinking that a world without such familiar things would be a bizarre place indeed. But that is just how it was for most of the history of life on Earth.

The Earths surface now holds a vast array of skeletons, from microscopic to gigantic. Some piles of skeletons, like the Great Barrier Reef of Australia, are so large that they can be seen from space, while others, visible only through powerful microscopes, show exquisite preservation of minute structures from hundreds of millions of years ago. Specimens of the most spectacular skeletons have been avidly sought by humans, even in antiquity, and their power to awe remains undimmed. Looking from another perspective, skeletons en masse, assembled down the years and stored within layers of rock, have been crucial in controlling some of the Earths most important chemical cycles, and in maintaining a habitable climate on our planet.

In this book we look at skeletons from many angles, and encompass all of those mineral frameworks that have allowed life to engineer the planet we live on. We look at the skeleton innovations that occurred in deep antiquity, within tiny cells that built forms of scaffolding for themselves, and how this led to the eventual evolution of the familiar skeletons of today. We explain the very different strategies by which skeletons can be built, and we show how these frameworks can engineer an extraordinary diversity of bodies, shapes, sizes, and solutions to the problem of living.

Looking at life on Earth from the perspective of skeletons can help to answer some big questions. Why are skeletons made from certain materials? Why do some animals have their skeletons on the outside, and others on the inside? What advantages have skeletons conferred to animals and plants, and what lifestyle possibilities have they enabled? And how have they re-engineered our planet, in providing the framework for sophisticated networks of life that fashioned the evolution of Earths oceans, land, and atmosphere.

How have skeletons, too, helped human life? The bones of dinosaurs and marine reptiles are not only prized as spectacular museum pieces, to give us glimpses of the Earths ancient and dramatic past. Farmers have used them, too, in a much more prosaic and functional way, albeit in a way that would dismay a palaeontologist. And, now, as we enhance our own skeletons technologically, and build new skeletons to allow us to explore our world and other worlds, scientists can look to the structure of bone and shell that has evolved over millions of years, to provide inspiration as they construct the new material fabrics of our society.