A Short History of Nearly Everything

by Bill Bryson

On a diagram of the solar system to scale, with the Earth reduced to about the diameter of a pea, Jupiter would be over 300 metres away and Pluto would be two and a half kilometres distant (and about the size of a bacterium, so you wouldn’t be able to see it anyway). On the same scale, Proxima Centauri, our nearest star, would be 16,000 kilometres away.

‘There is a critical threshold where the natural biosphere stops buffering us from the effects of our emissions and actually starts to amplify them.’ The fear is that there would be a very rapid increase in the Earth’s warming. Unable to adapt, many trees and other plants would die, releasing their stores of carbon and adding to the problem.

Whatever prompted life to begin, it happened just once. That is the most extraordinary fact in biology, perhaps the most extraordinary fact we know.

Perhaps the most extraordinary survival yet found was that of a Streptococcus bacterium that was recovered from the sealed lens of a camera that had stood on the Moon for two years

Thomas Gold of Cornell University has estimated that if you took all the bacteria out of the Earth’s interior and dumped them on the surface, they would cover the planet to a depth of 15 metres

Of the twenty-three main divisions of life, only three – plants, animals and fungi – are large enough to be seen by the human eye33

you imagine the 4,500 million years of Earth’s history compressed into a normal earthly day5, then life begins very early, about 4 a.m., with the rise of the first simple, single-celled organisms, but then advances no further for the next sixteen hours. Not until almost eight-thirty in the evening, with the day five-sixths over, has the Earth anything to show the universe but a restless skin of microbes. Then, finally, the first sea plants appear, followed twenty minutes later by the first jellyfish and the enigmatic Ediacaran fauna first seen by Reginald Sprigg in Australia. At 9.04 p.m. trilobites swim onto the scene, followed more or less immediately by the shapely creatures of the Burgess Shale. Just before 10 p.m. plants begin to pop up on the land. Soon after, with less than two hours left in the day, the first land creatures follow. Thanks to ten minutes or so of balmy weather, by 10.24 the Earth is covered in the great carboniferous forests whose residues give us all our coal, and the first winged insects are evident. Dinosaurs plod onto the scene just before 11 p.m. and hold sway for about three-quarters of an hour. At twenty-one minutes to midnight they vanish and the age of mammals begins. Humans emerge one minute and seventeen seconds before midnight. The whole of our recorded history, on this scale, would be no more than a few seconds, a single human lifetime barely an instant.

Indeed, it has been suggested that there isn’t a single bit of any of us – not so much as a stray molecule8 – that was part of us nine years ago. It may not feel like it, but at the cellular level we are all youngsters.

At one point between three million and two million years ago, it appears there may have been as many as six hominid types co-existing in Africa. Only one, however, was fated to last: Homo, which emerged from the mists beginning about two million years ago.

Oxford scientist named Bryan Sykes had just produced a popular book called The Seven Daughters of Eve in which, using studies of mitochondrial DNA, he had claimed to be able to trace nearly all living Europeans back to a founding population of just seven women – the ‘daughters of Eve’ of the title – who lived between ten thousand and forty-five thousand years ago in the time known to science as the Palaeolithic.

According to the University of Chicago palaeontologist David Raup, the background rate of extinction on Earth throughout biological history has been one species lost every four years on average. According to Richard Leakey and Roger Lewin in The Sixth Extinction, human-caused extinction now may be running at as much as 120,000 times that level5.