Taxonomy term


Precambrian rumblings of the Cambrian Explosion

The Cambrian Explosion, when the ancestors of most of today’s animal groups began appearing in the fossil record about 542 million years ago, was — as the name suggests — a geologically abrupt event. Paleontologists have long thought of the event as marking a boundary between distinct Precambrian and Cambrian faunas. In new research published in Geology, however, scientists report that small, shelly fossils once thought to occur only in Cambrian rocks have been found in rocks dating to the late Ediacaran, just before the Cambrian, implying an earlier start to the explosion than previously thought.

11 Jul 2017

Weak magnetic field may have triggered Earth's first mass extinction

For about the first 3 billion years of life, the only living organisms on Earth were microscopic. The Ediacaran Period, between 635 million and 541 million years ago, saw the rise of the first large-scale life, most of which then went extinct at the period’s close — a collapse that scientists have yet to explain. Now, researchers may have found one of the extinction’s drivers: rapid flip-flopping of Earth’s magnetic field — wherein the field’s north and south poles reverse — that could have left the planet and Ediacaran organisms vulnerable to bombardment by harmful cosmic radiation.

08 Jul 2016

Soft-bodied fossils cast in fool's gold

Most of the fossil record is composed of hard bones and shells — only a handful of places preserve fossils of soft-bodied organisms from early in Earth’s evolutionary history. The processes by which these delicate fossils form are not well understood, but a new study looking at an assemblage of 550-million-year-old soft-bodied fossils found in China sheds light on one potential mechanism.

10 Apr 2015