Taxonomy term

extinction

Brachiopod die-off signaled mid-Permian mass extinction

Since the explosion of complex lifeforms before the turn of the Cambrian, the expansion of life on Earth has been punctuated by a quintet of global mass extinctions known as the “Big Five.” The biggest of these happened toward the end of the Permian Period about 252 million years ago, when 95 percent of all species went extinct. In a new study, scientists have proposed that a sixth global extinction, about 10 million years before the End-Permian die-off, should be added to the list.

16 Jul 2015

Limited ranges left ammonites vulnerable to extinction

Why spiral-shelled, ocean-faring ammonites went extinct at the end of the Cretaceous while the nautilids — the ammonites’ less abundant and less diverse cephalopod relatives — survived has long puzzled paleontologists. Nautilids tended to dwell deeper in the ocean than ammonites, perhaps keeping them farther out of harm’s way after the asteroid struck, which likely led to acidification of the ocean surface. Now, a new study suggests that the animals’ geographic range may have contributed to which ones lived and which ones died.

13 Dec 2014

Extra rib may be sign of mammoth decline

High rates of a congenital defect in woolly mammoths may offer evidence that inbreeding and environmental stress contributed to the animals’ demise during the Late Pleistocene, according to a new analysis of fossil mammoth neck bones.

26 Aug 2014

Do impacts trigger extinctions? Impact theory still controversial

The revolution started with a bang in 1980. For some, this revolution became a religion, even an orthodoxy. The true believers became proselytes and began to see signs supporting their viewpoint everywhere. But each time the proselytes claimed to have found yet another example in support of their “religion,” naysayers and doubters emerged. Two sides formed, each loudly castigating and questioning their opponents.

This back-and-forth ideological debate describes both the historical and still-ongoing struggle over a purported cause of mass extinctions: the meteor impact theory.

23 Jun 2010

Extinction-era coal linked to Chinese cancer epidemic

At the close of the Permian, 252 million years ago, conditions on Earth took a turn for the worse, nearly wiping out life on land and at sea in the planet’s most severe extinction event. Now, eons later, geologists are implicating a coal seam that dates to the “Great Dying” at the Permian-Triassic boundary in one of the modern world’s worst cancer epidemics.

14 Jan 2010

Deciphering mass extinctions

What the planet’s past mass extinctions tell us about the future of life on Earth

The crash-landing of a 10-kilometer-wide asteroid 65 million years ago made for a very bad day for dinosaurs — or one very lucky day for mammals.

02 Sep 2009

Comet finished off North American big game animals, cooled the planet?

Fires from a comet shower may have killed off the big game in North America about 13,000 years ago, scientists say. Those extinctions have long been attributed either to an abrupt return to glaciation known as the Younger Dryas event or to over-hunting. But now, a team of scientists has found tiny, nanoparticle-sized diamonds in sediments from the Younger Dryas — signs that a cosmic impact may have ultimately been behind both the cold period and the extinctions.

02 Jan 2009

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