The Lost World by Michael Crichton
Introduction:
“Extinction at the K-T Boundary”
The late twentieth century has witnessed a remarkable growth in scientific interest in the subject of extinction.
It is hardly a new subject – Baron Georges Cuvier had first demonstrated that species became extinct back in 1786, not long after the American Revolution. Thus the fact of extinction had been accepted by scientists for nearly three-quarters of a century before Darwin put forth his theory of evolution. And after Darwin, the many controversies that swirled around his theory did not often concern issues of extinction.
On the contrary, extinction was generally considered as unremarkable as a car running out of gas. Extinction was simply proof of failure to adapt. How species adapted was intensely studied and fiercely debated. But the fact that some species failed was hardly given a second thought. What was there to say about it? However, beginning in the 1970s, two developments began to focus attention on extinction in a new way.
The first was the recognition that human beings were now very numerous, and were altering the planet at a very rapid rate-eliminating traditional habitats, clearing the rain forest, polluting air and water, perhaps even changing global climate. In the process, many animal species were becoming extinct. Some scientists cried out in alarm; others were quietly uneasy. How fragile was the earth’s ecosystem? Was the human species engaged in behavior that would eventually lead to its own
extinction?
No one was sure. Since nobody had ever bothered to study extinction in an organized way, there was little information about rates of extinction in other geological eras. So scientists began to look closely at extinction in the past, hoping to answer anxieties about the present.
The second development concerned new knowledge about the death of the dinosaurs. It had long been known that all dinosaur species had become extinct in a relatively short time at the end of the Cretaceous era, approximately sixty-five million years ago. Exactly how quickly those extinctions occurred was a subject of long-standing debate: some paleontologists believed they had been catastrophically swift, others felt the dinosaurs had died out more gradually, over a period of ten thousand to ten million years – hardly a rapid event.
Then, in 1980, physicist Luis Alvarez and three coworkers discovered high concentrations of the element iridium in rocks from the end of the Cretaceous and the start of the Tertiary – the so-called K-T boundary. (The Cretaceous was shorthanded as “K” to avoid confusion with the Cambrian and other geological periods.) Iridium is rare on earth, but abundant in meteors. Alvarez’s team argued that the presence of so much iridium in rocks at the K-T boundary suggested that a giant meteorite, many miles in diameter, had collided with the earth at that time. They theorized that the resulting dust and debris had darkened the skies, inhibited photosynthesis, killed plants and animals, and ended the reign of the dinosaurs.
This dramatic theory captured the media and public imagination. It began a controversy which continued for many years. Where was the crater from this meteor? Various candidates were proposed. There were five major periods of extinction in the past-had meteors caused them all? Was there a twenty-six-million-year cycle of catastrophe? Was the planet even now awaiting another devastating impact?
After more than a decade, these questions remained unanswered. The debate raged on – until August 1993, when, at a weekly seminar of the Santa Fe Institute, an iconoclastic mathematician named Ian Malcolm announced that none of these questions mattered, and that the debate over a meteoric impact was “a frivolous and irrelevant speculation.”
“Consider the numbers,” Malcolm said, leaning on the podium, staring forward at his audience. “On our planet there are currently fifty million species of plants and animals. We think that is a remarkable diversity, yet it is nothing compared to what has existed before. We estimate that there have been fifty billion species on this planet since life began. That means that for every thousand species that ever existed on the planet, only one remains today. Thus 99.9 percent of all species that ever lived are extinct. And mass killings account for only five percent of that total. The overwhelming majority of species died one at a time.”