Study: Life on land began 2.6 billion years ago

Life on Earth may have crossed the line from sea to land earlier than previously thought, according to researchers

November 30, 2000
Web posted at: 12:55 PM EST (1755 GMT)

LONDON, England (Reuters) -- Life on land began more than 1.4 billion years earlier than scientists had thought, geologists said Wednesday.

Scientists have known that microorganisms have lived in oceans for about 3.8 billion years, but they weren't sure when early life forms made the transition to land.

The oldest proof of terrestrial life had been found in 1.2 billion-year-old fossils from Arizona, but scientists in South Africa and the United States have now discovered organic matter in 2.6 billion-year-old South African rocks.

"This places the development of terrestrial biomass more than 1.4 billion years earlier than previously reported," Yumiko Watanabe, of the Pennsylvania State University, said in a study in the science journal Nature.

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Knowing when microorganisms made the transition from oceans to land is important because it gives scientists new information about the presence of oxygen that is needed to sustain life and the formation of the earth's protective ozone shield.

Hiroshi Ohmoto, a geochemist at Penn State who contributed to the research, believes there are even earlier samples of life on land.

He and his colleagues are planning to scour sites in Australia, Canada and elsewhere to find them.

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Pennsylvania State University

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