Two centuries after the birth of Shrewsbury’s most famous son, the naturalist Charles Darwin, there is still no evolutionary explanation for why humans blush, a biologist wrote in a leading scientific magazine today.

Frans de Waal, professor of primate behaviour at Emory University, Georgia, US, identified blushing as the biggest gap in evolutionary theory.

Writing in the New Scientist, he said: “We’re the only primate that blushes in response to embarrassing situations (shame) or when caught in a lie (guilt).”

He added: “One wonders why we needed such an obvious signal to communicate these self-conscious feelings. 

“Blushing interferes with the unscrupulous manipulation of others.” 

He speculated on whether early humans were subjected to selection pressures to keep them honest. 

The magazine asked some of the world’s leading evolutionary biologists to identify the biggest gaps remaining in Darwin’s theory to mark the bicentenary of the scientist’s birth. 

More than one argued that there is still no evolutionary explanation for the origin of life itself. 

Kenneth Miller, professor of biology at Brown University, Rhode Island, in the US, said: “We know a great deal about the creative chemistry of the early Earth, but not yet enough to solve this problem.” 

Chris Wills, professor of biology at the University of California, said: “The gap between . . . a collection of molecules and even the most primitive cell remains enormous.” 

Meanwhile, a huge piece of public art dedicated to Charles Darwin and entitled “Primordial Soup” is to be created. The Mary Webb School and Science College was successful in securing an Awards for All grant of £10,000 through the Heritage Lottery Fund.

The application was made by the art department in conjunction with professional artist Clinton Challoner. Clinton, who is an expert wood carver, will be leading the project to produce a major public artwork in Shrewsbury.

Students from Belvidere School will also benefit from the funding by working collaboratively with the artist and the Mary Webb School.  

Design and wood sculpture workshops will take place at both schools and also at Shrewsbury’s Quarry, where members of the public and youth groups will be able to participate in open-air workshops under guidance from the artist.

The event is one of many taking place in Shrewsbury this year to mark the 200th anniversary of Darwin’s birth on February 12.

By Sarah Bullock