The Story of Life by Richard Southwood, Oxford University Press, £19.99, ISBN 0198525907 Reviewed by Lynn Dicks
IN THE beginning, Earth was hostile: alkaline, oxygen free and bombarded with asteroids. If you believe, as Richard Southwood does, that life originated here, his book tells you its entire history. How the first membranes and nucleic acids transformed into the myriad plant, animal and microbial life we know today. It is some story.
There’s high drama as the entire planet is encased in ice just as life was getting a grip, and great success stories. Evolution goes off like a bomb. Take the dinosaurs. Their ancestors lived discretely, a burning fuse, for millions of years before they suddenly took over. Along the way, at least five mass extinctions killed large proportions of all species.
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Besides being a gripping yarn, The Story of Life is an impeccable review of the science. Explaining how you work out the story from scant evidence, Southwood draws on an enormous breadth of knowledge, from biochemistry to ecology, geology to animal behaviour. How do we know that life began 3750 million years ago? And how sure are we that this is the right date? Why did it take 50 million years for the first land animals to learn to eat plants as well as each other?
I was lucky enough to attend the lecture course at Oxford University on which this book is based. I clearly recall the fabulous maps of the land masses as they shifted around, forming two giant continents, then one, before splitting into their current shapes. The effect of these movements on evolution has been profound. The aridity of the great continent, Pangaea, around 250 million years ago, may have been vital to the success of early conifers, such as the surviving monkey puzzle tree.
Understandably, dealing with every group of organisms, detail is limited and, given that the book is certain to be devoured by undergraduates, it would have benefited from more extensive references. But he gives us a wonderful perspective. Spiders, in Southwood’s world, are the only land-based filter feeders, using their webs in the same way that sea anemones use their tentacles. The international ban on commercial whaling is absolutely justifiable in the light of the extinction of animals, such as the giant armadillos, that were probably hunted to death 12,000 years ago.
We are in the thick of another species radiation dominated by mammals – large, even-toed ungulates and one rather numerous, naked primate.
Curiously enough, some land mammals that returned to the sea, dolphins and seals, have repeated something that had happened before. And some oddities, such as elephants, are remnants of types that were commonplace in past eras. The story does not end here. Whatever people do to the planet – and Southwood provides a thorough description of how we are changing it – one thing is certain. Life will continue. The fuse may even now be burning for the next great explosion.