Evidence supports theory that humans evolved in grasslands

JUNE 11, 2016

by Chuck Bednar

Researchers from the Columbia University Lamont-Doherty Earth Observatory have discovered new evidence to support the theory that key human traits, including large brains and the ability to walk on two legs, evolved as our ancestors adapted to living in open grasslands.

Writing in a special human-evolution issue of the journal Proceedings of the National Academy of Sciences, postdoctoral research scientist Kevin Uno and his colleagues found a 24 million year old vegetation record buried deep within seabed sediments off the coast of eastern Africa.

This vegetation is the longest and most complete record of ancient plant life discovered to date in the purported birthplace of humanity, modern-day Kenya and Ethiopia, the researchers noted in a statement. It also indicates that between 24 million and 10 million years ago, well before the first human ancestors arose, the region was dominated by woodlands with few grasses.

That all changed due to a dramatic shift in climate, and within a few million years time, grasses became dominant – a trend that continued throughout the entire course of  human evolution, Uno and his colleagues said. As our ancestors adapted to these changes, they evolved physically, their diets became more flexible, and their social structures grew in complexity.

Genetic evidence suggests that early hominids first split from other apes between six and seven million years ago, and many scientists believe that it was the shift from dense forests to savannas in eastern Africa that served as the catalyst for their eventual development into modern humans. The new study indicates that the rise of grasslands had a tremendous impact on hominins.

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Restoring grasslands: Ant diversity indicates restored grasslands

Date:

June 9, 2014

Source:

South Dakota State University

Summary:

When it comes to restoring grasslands, ecologists may have another way to evaluate their progress -— ants. The more diverse the ant population, the closer a restored section of grassland is to its original state, according to one expert. When it comes to native grasslands, ants are “ecosystem engineers.”

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UK wildlife rich grasslands vanishing

April 2014: There has been a dramatic decline in our remaining wildlife-rich grasslands say conservationists putting many species at risk.

“Wildlife-rich grasslands have been in trouble for decades, but our newly collated information shows that the remaining hay meadows and flower-rich pastures are still at risk,” says Stephen Trotter, The Wildlife Trusts’ Director. “We’re seeing an insidious yet catastrophic decline. The pressures are enormous: from development and changes in agricultural practices, to neglect.”

The Wildlife Trusts have been collecting information on the state of valuable grassland sites in England such as ancient meadows, pastures and road verges. They have found that nearly a quarter of wildlife sites have been lost across many counties in the UK, while in the Lake District National Park they found a staggering 183.26 hectares (82 per cent) has been de-selected as Local Wildlife Sites. 

The Wildlife Trusts are calling for a full review of existing protection for environmentally important grasslands. They are asking the Government to:

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In grasslands remade by humans, animals may protect biodiversity: Grazers let in the light, rescue imperiled plants

Date:

March 9, 2014

Source:

University of Maryland

Summary:

A study of grasslands on six continents suggests a way to counteract the human-made overdose of fertilizer that threatens the biodiversity of the world's prairies. The solution originates in nature: let grazing animals crop fast growing grasses, which have a competitive advantage in an over-fertilized world. The grasses block sunlight from ground level, but herbivores make light available to other plants.

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