For most of the nearly 3.5 billion years of documented life on Earth, creatures were simple, dominated by organisms such as bacteria, algae and fungi (SN: 10/13/18, p. 10).
Then, beginning about 541 million years ago, life quickly diversified into an array of new, complex forms. This flourishing, called the Cambrian explosion, took place within about 25 million years. Fossils from the...
Along the banks of China’s Danshui River lies a treasure trove of fossils that may rival the most famous Cambrian fossil assemblage of all, Canada’s Burgess Shale. The roughly 518-million-year-old site contains a dizzying abundance of beautifully preserved weird and wonderful life-forms, from jellyfish and comb jellies to arthropods and algae.
So far, researchers led by paleontologist...
SAN FRANCISCO — Earth may have been a water world for much of its history, a new proposal contends. Just like in the Kevin Costner movie, the continents would have been mostly submerged below sea level. Previous proposals have suggested that Earth’s land area has remained comparatively unchanged throughout much of geologic time.
But geoscientist Cin-Ty Lee of Rice University in Houston...
Earth’s long history starts with an epic preamble: A collision with a Mars-sized space rock rips into the young planet and jettisons debris that forms the moon. Over the next few billion years, plot twists abound. The oceans form. Life appears. Solar-powered microbes breathe oxygen into the air. Colossal environmental shifts reshape the planet’s surface and drive the evolution of early life....
The diversification of early animals may have been suffocated by a lack of oxygen. A new analysis of ancient rocks offers a glimpse of conditions in the millions of years leading up to the proliferation of animals. The data suggest that oxygen levels were less than 1 percent of today’s levels, low enough that they may have stalled the emergence of animal life.
Scientists have been...
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Some of the largest early animals may have used spiny limbs to filter their food rather than impale it.
Fossils found in northern Greenland suggest that, like other predators 520 million years ago, Tamisiocaris borealis, a distant lobster relative, had two long, spiny limbs that jutted out from its face. But unlike other predators, T. borealis’ limbs also had...