PARIS, Aug 2: Scientists have discovered the reason for a phenomenon that supported Charles Darwin’s theory of evolution — the varied shape of finches’ beaks — according to Thursday’s issue of the journal Nature.

When the British naturalist Darwin disembarked on the Pacific archipelago of the Galapagos Islands in 1835, he found 14 separate species of finch, which were distinguishable by a key feature — the shape of their beaks.

Although all are descended from a common ancestor, their beaks vary from the long, pointed one of the so-called cactus finch, to the ground finch’s deep, wide protuberance.

The different shapes and lengths reflect differences in the species’ diet. The cactus finch uses its long beak to pick out insects hiding in plants, while the ground finch uses its wide one to scoop morsels from the ground.

So a team of scientists based in the United States sought to discover what gave the beaks their different shapes.

Using a genetic analysis technique called DNA microarray analysis to study the differences between five species of finch, they found that the longer, pointed beaks contained more calmodulin, a protein molecule that binds calcium in cells.—AFP