Stephanie Singleton
MOST accounts of life on Earth begin little more than half a billion years ago. That is when an evolutionary burst of creativity produced the ancestors of almost all animals and plants alive today. Following this “Cambrian explosion”, life’s story is one of fish, amphibians, insects, land plants, the rise and fall of the dinosaurs, and ultimately the emergence of humans. It is an epic tale – but it spans just one-eighth of life’s history.
The problem is that although animals and plants have left abundant fossils, Precambrian rocks contain almost no traces of earlier life. This vexed Charles Darwin, who wrote in On the Origin of Species: “To the question why we do not find records of these vast primordial periods, I can give no satisfactory answer.” Since then, a few fossilised remains have been found, but these are mostly microscopic blobs, reluctant to give up their secrets. Yet, in recent years, ingenious researchers have found new ways to lift the lid on life’s black box.
This is the story of the first 3.5 billion years. It is a tale dominated by single-celled organisms, but it is also one of cataclysmic change. It encompasses the birth of the continents, the greatest act of chemical pollution ever committed, and a freak evolutionary event that may never have happened anywhere else in the universe. It is an epic journey, so buckle up.
In the beginning was Earth. It formed some 4.54 billion years ago from rocks and dust and, soon afterwards, was smacked in the face by another baby planet (or possibly several small ones). The impact melted Earth’s surface and …
