Survivors by Richard Fortey

There are three main reasons why survivors hold our gaze. One is that their survival may hold lessons for ours: we're keen to know what they have done right. Another is that their presence connects us with a past now overlain by newer historical strata. The third is that they tease our sense of fate. We are awed by the explorer who prises survival out of grit and thin air, salute the passing of the last veterans of the First World War, and are momentarily cheered by the kitten who emerges from a washing machine alive.

We are also impressed when we look at nature and see forms that have endured for aeons without the benefit of the wits and opposable thumbs that we enjoy. The thought that some of these may see us out offers a frisson of misanthropic relish. Thus Ambrose Bierce hailed the fly in his Devil's Dictionary: "He wantoned in the eyebrows of our fathers; he will skate upon the shining pates of our sons." Cockroaches foraged beneath trees that ended up as coal; it's said they would inherit the world if it were devastated by nuclear war. The ginkgo trees of Hiroshima unfurled their leaves, much the same in shape as those of their ancestors a hundred million years ago, the year after they were blasted by the first atomic attack.

Richard Fortey's view of life is not soured by misanthropy, and his generosity of spirit extends almost, but not quite, to cockroaches. Formerly a palaeontologist at the Natural History Museum, he is a true natural historian, a species whose own survival is a cause for celebration. He is drawn to survivors because they connect the patterns of life today to the patterns of its history. He perceives the lives of natural forms as narratives, and is duly awed by "biographies" that span hundreds of millions of years.

His search for survivors takes the form of an intercontinental ramble, from Mistaken Point in Newfoundland to Useless Loop in Australia. Like his previous books, which include Trilobite! and The Earth: An Intimate History, the text is a gently tangled bank of reflections and excursions. He does not strive for effect but does enjoy the odd flourish, such as his description of the Norfolk Island pine as "a tiered architectural essay of a tree".

Nor does he demand charisma in his specimens. The oldest survivors are large lumps of accreted microbial slime known as stromatolites. They offer a glimpse of what the living world may have looked like a couple of billion years ago. Judging by the accompanying photo (the book is well illustrated, and will be complemented by a documentary on BBC4) it looked rather like an English Channel beach at low tide. Other examples include lampreys, tubular fish with the beginnings of a spinal cord but no jaw, and horsetails, those bristly green primitives that colonise water margins to form miniature models of the ancient coal forests.

These are not exotically located survivors either, in remote refuges or infernal cracks in the earth's crust. They are at home in the Home Counties, and lampreys lurk in the stream that flows behind Fortey's childhood home in Berkshire.

Whether exotic or domestic, enduring forms stand out in a world of endless evolution. As Darwin put it: "Natural selection is daily and hourly scrutinising... every variation ... silently and insensibly working, whenever and wherever opportunity offers." What is it about the form of the shark, the crocodile or the monkey-puzzle tree that has continued to pass natural selection's scrutiny when so many other forms have come and gone?

I once had the opportunity to ask the great evolutionary theorist George Williams about this. "That is a very interesting question," he declared, but elaborated no further. Although Fortey does not share Williams' inclination to reserve his insights for his peers, he has little more to say on the subject. As a naturalist he is absorbed by the tapestry of life, the variety of its patterns, rather than the weaving or the threads. While it's been a pleasure to follow him on his grand ramble, I continue to wait in hope for an evolutionist who will explain just what these survivors have been doing right.

Marek Kohn's most recent book is 'Turned Out Nice' (Faber & Faber)