A Worcestershire academic has helped change the scientific world's understanding of how Charles Darwin came to develop his theory of evolution.

Dr Mark Whitehorn, a geneticist and business intelligence expert from University College Worcester, collaborated with scientists from Cambridge University to show how Darwin's university mentor had set him on course to his revolutionary theory long before he sailed aboard HMS Beagle.

The findings were made after Prof John Parker, a botanist at the University of Cambridge and Gina Murrell, also from Cambridge, noticed oddities in the university's renowned herbarium - a paper record of plant species.

Compiled by Professor John Henslow from 1821 and 1835, it catalogues 10,172 plants attached to 3,654 herbarium sheets.

The Cambridge duo noticed when Henslow collected, dried and categorised the plants he went to great lengths to illustrate the different shapes and sizes which could occur in any species.

"Henslow would ask people to send him different examples from all parts of the country and use them to illustrate variability to his students," said Dr Whitehorn. "Henslow was not just identifying plants; he was organising his herbarium to emphasise variation within species.

"Remarkably, he seems to be the only British botanist at the time doing this. Other herbariums would show just one example of each plant.

" Charles Darwin was Henslow's biggest fan. In fact, he did not go to anyone else's lectures for three years. We also discovered he was a specimen collector for Henslow."

For 160 years it was believed Darwin's interest in variation arose aboard the Beagle when he arrived at the Galapagos Islands.

"What we believe happened is Henslow sent Darwin off on the Beagle saying 'go and see if this happens across the world'. Darwin sent almost all of the samples he collected while on the Beagle to Henslow.

" We believe Henslow launched Darwin's mind during those undergraduate days on an intellectual voyage that led from a belief in speciesstability to the mutability expressed in Origin of Species." Charles Darwin