VOL THR EE / ISSU E T WO O R I G I N, EVO LU T I O N, E XT I N C T I O N T H E E PIC ST ORY OF L I FE ON E A RT H £9.99 0 2 9 772054 638003 THE COLLECTION Life story VOL 3 / ISSUE 2 LIFE ON EARTH: ORIGINS, EVOLUTION, EXTINCTION NEW SCIENTIST THE COLLECTION 110 High Holborn, London WC1V 6EU +44 (0)20 7611 1202
[email protected] Editor-in-chief Graham Lawton Editor Alison George Art editor Craig Mackie Pictures New Scientist picture desk Subeditor Julia Brown Graphics Dave Johnston Production editor Mick O’Hare Project manager Henry Gomm Publisher John MacFarlane © 2016 Reed Business Information Ltd, England New Scientist The Collection is published four times per year by Reed Business Information Ltd ISSN 2054-6386 Printed in England by Precision Colour Printing, Telford, Shropshire, and distributed by Marketforce UK Ltd +44(0)20 3148 3333 Display advertising +44(0)20 7611 1291
[email protected] Cover image Aixsponza HOW did life begin? This is one of the eternal questions. All cultures have a creation story, but modern science has the best one of all – a near-complete account of how our planet went from a barren lump of rock to one covered in a rich diversity of plants, animals and microbes. For almost a billion years after it formed, Earth was a lifeless place with hellish conditions. But around 3.8 billion years ago, after the surface had cooled and oceans formed, something amazing happened. Out of Earth’s primordial chemicals arose an entity capable of replicating itself. Life was born. The rest, as they say, is prehistory. The forces of evolution worked on this simple life form and its descendants to create all manner of useful adaptations including a system to capture energy from the sun (photosynthesis), biological computers (brains) and even a biological wheel. We will probably never know exactly how this first life arose or what it was like, but there are many other mysteries we can hope to solve. This issue of New Scientist: The Collection tackles these questions. It tells the epic story of the only living planet we know of in the universe, from life’s origins to the watershed moments in its history. Chapter 1 is about the dawn of life. Charles Darwin imagined that life arose in “some warm little pond”, but there are many other possible cradles of life. Where and when did it happen? What ingredients were needed, and was the event inevitable? Chapter 2 explores the key steps in the early development of life. For the first 1.5 million years of its existence, life consisted of simple microbes, but then things got more interesting. Cells developed internal “organs” and multicellular life eventually followed. What drove this process? What were the first complex creatures on Earth