British naturalist Charles Darwin is credited with the theory of evolution, but a crucial part of his theory came from his mentor, John Stevens Henslow, a lesser-known Cambridge University professor.

Henslow may have been forever relegated to obscurity were it not for database analytics. For more than two years, a team of researchers based at Cambridge worked to uncover a secret hidden in Henslow's 160-year-old herbarium (his collection of plants).

Henslow's herbarium consists of paper sheets with more than 10,000 dried plant samples on them that he and others collected. Henslow documented the samples' origins and species, among other data.

According to Mark Whitehorn, a database expert who worked on the project, once this information was transferred into a database, researchers were able to draw connections from the plant samples, such as when two collectors may have been travelling together.

They reached a striking conclusion: the concept of variation – meaning differences within a species necessary for its survival as a whole – was first observed by Henslow, Whitehorn says. "He trained Darwin to observe variations between the species," he claims.