Tag Archives: richard lane

Six Million Years of African Savanna

*Open, grassy environments accompanied human evolution*

Scientists using chemical isotopes in ancient soil to measure prehistoric tree cover–in effect, shade–have found that grassy, tree-dotted savannas prevailed at most East African sites where human ancestors and their ape relatives evolved during the past six million years.

“We’ve been able to quantify how much shade was available in the geological past,” says University of Utah geochemist Thure Cerling, lead author of a paper titled “Woody cover and hominin environments in the past 6 million years” on the results in this week’s issue of the journal Nature. (more…)

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Earth’s Sixth Mass Extinction: Is It Almost Here?

*Steep decline of many animal species warns that Earth is on the brink*

With the steep decline in populations of many animal species, scientists have warned that Earth is on the brink of a mass extinction like those that have occurred just five times during the past 540 million years.

Each of these “Big Five” saw three-quarters or more of all animal species go extinct.

In results of a study published in this week’s issue of journal Nature, researchers report on an assessment of where mammals and other species stand today in terms of possible extinction compared with the past 540 million years.

They find cause for hope–and alarm. (more…)

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Oldest Fossils of Large Seaweeds, Worm-like Animals Tell Story of Ancient Oxygen

*Geobiologists uncover Davy Jones Locker of fossils near small village in south China*

Almost 600 million years ago, before the rapid evolution of life forms known as the Cambrian explosion, a community of seaweeds and worm-like animals lived in a quiet deep-water niche near what is now Lantian, a small village in south China.

Then they simply died, leaving some 3,000 nearly pristine fossils preserved between beds of black shale deposited in oxygen-free and unbreathable waters. (more…)

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