The Sixth Extinction: An Unnatural History

by Elizabeth Kolbert

Darwin recognized that just as the features of the inorganic world—deltas, river valleys, mountain chains—were brought into being by gradual change, the organic world similarly was subject to constant flux.

It may be said that natural selection is daily and hourly scrutinising, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good; silently and insensibly working, whenever and wherever opportunity offers.

“The appearance of new forms and the disappearance of old forms” were, Darwin wrote, “bound together.”

Frederik Christian Raben,

Pinguinus impennis—

George Cartwright,

John James Audubon

Jean-Baptiste Charcot,

for all practical purposes therefore we may speak of it as a thing of the past”—

Alfred Russel Wallace

“It came to me like the direct revelation of a higher power,”

“and I awoke next morning with the consciousness that there was an end of all the mystery in the simple phrase, ‘Natural Selection.’

At the heart of Darwin’s theory, as one of his biographers has put it, is “the denial of humanity’s special status.”

Gola del Bottaccione,

Walter Alvarez,

In the gorge, he discovered the first traces of the giant asteroid that ended the Cretaceous period and caused what may have been the worst day ever on planet earth.

“plate tectonics revolution”

scaglia rosso,

“In science, sometimes it’s better to be lucky than smart,”

“Extraterrestrial Cause for the Cretaceous-Tertiary Extinction,”

he asserted that the faunal gap was just a gap in the fossil record.

a history of the world imperfectly kept,

“wide intervals of time” were probably unaccounted for.

we invoke cataclysms to desolate the world!”

The uniformitarian view precluded sudden or sweeping change of any kind. But the more that was learned about the fossil record, the

more difficult it was to maintain that an entire age, spanning tens of millions of years, had somehow or other gone missing.

“shocked quartz.”

Finally, a hundred-and-fifty-kilometre-wide crater was discovered or, more accurately, rediscovered, beneath the Yucatán Peninsula.

found to contain a layer of glass—rock that had melted, then rapidly cooled—right at the K-T boundary.

Ammonites floated through the world’s shallow oceans for more than three hundred million years, and their fossilized shells turn up all around the world.

After the initial heat pulse, the world experienced a multiseason “impact winter.”

Marine ecosystems effectively collapsed, and they remained in that state for at least half a million, and perhaps as many as several million, years.

In general, the more that’s been learned about the K-T boundary, the more wrongheaded Lyell’s reading of the fossil record appears. The problem with the record is not that slow extinctions appear abrupt. It’s that even abrupt extinctions are likely to look protracted.

Lilliput effect.

Everything (and everyone) alive today is descended from an organism that somehow survived the impact. But it does not follow from this that they (or we) are any better adapted. In times of extreme stress, the whole concept of fitness, at least in a Darwinian sense, loses its meaning: how could a creature be adapted, either well or ill, for conditions it has never before encountered in its entire evolutionary history?

“On the Perception of Incongruity: A Paradigm.”

revealed how people process disruptive information.

At the point the anomaly becomes simply too glaring, a crisis ensues

The Structure of Scientific Revolutions,

Data that did not fit the commonly accepted assumptions of a discipline would either be discounted or explained away for as long as possible.

The more contradictions accumulated, the more convoluted the rati...

“Though the world does not change with a change of paradigm, the scientist afterward works in a different world”

standard geology, holds that conditions on earth change only very slowly, except when they don’t.

“long periods of boredom interrupted occasionally by panic.”

Those animals and plants that made it through the Ordovician extinction “went on to make the modern world,” the British paleontologist Richard Fortey has observed.

It’s shaped like a set of false eyelashes, but very small, as if for a Barbie.

The study revealed that in addition to the five major mass extinctions, there had been many lesser extinction events. When all of these were considered together, a pattern emerged: mass extinctions seemed to take place at regular intervals of roughly twenty-six million years.

More significantly, upon further analysis, the evidence for periodicity began to fall apart.

The end-Permian or Permo-Triassic extinction was the biggest of the Big Five, an episode that came scarily close to eliminating multicellular life altogether.

The current theory is that the end-Ordovician extinction was caused by glaciation.