Life
Seventy years ago, three discoveries propelled our understanding of how life on Earth began. But has the biggest clue to life’s origins been staring biologists in the face all along?
By Michael Marshall
The constant changing landscape of Earth may be a vital part of the story of the origins of the first ecosystems.
MARK GARLICK/Spl/Alamy;
HOW did life on Earth begin? Until 70 years ago, generations of scientists had failed to throw much light on biology’s murky beginnings. But then came three crucial findings in quick succession.
In April 1953, the race to uncover the structure of DNA reached its climax. Geneticists soon realised that its double helix form could help explain how life replicates itself – a fundamental property thought to have appeared at or around the origin of life. Just three weeks later, news broke of the astonishing Miller-Urey experiment, which showed how a simple cocktail of chemicals could spontaneously generate amino acids, vital for building the molecules of life. Finally, in September 1953, we gained our first accurate estimate for the age of Earth, giving us a clearer idea of exactly how old life might be.
At that point, we seemed poised to finally understand life’s origins. Today, conclusive answers remain elusive. But the past few years have brought real signs of progress.
For instance, we have found that life’s ability to replicate is not wholly reliant on DNA. We also have a far better idea of the conditions on early Earth when life first appeared – and we are beginning to conduct experiments into how it emerged that are much more sophisticated than Miller-Urey.
So, 70 years on from that incredible year of breakthroughs, how has our picture of life’s origins changed? And what remains to be figured out before we can satisfactorily answer biology’s ultimate question?
Definitions of life
“I think in the 50s we knew very little about life,” says …
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