Mountains may be cradles of evolution

London, September 26 (ANI): American scientists have suggested that growing mountains may give rise to new species, thus making them cradles of evolution.

"The major times of (species) diversification directly coincide with times of large tectonic events," Catherine Badgley, a palaeontologist at the University of Michigan in Ann Arbor, told Nature News.

Mountainous regions are known to harbour higher levels of species richness than other areas.

The reason, ecologists argue, is because mountains offer many different habitats in a relatively small geographical area.

For example, whereas ten square kilometres of plains offer just one habitat, the same area of mountain landscape can provide sloping meadows, peaks and cliffs, all with different temperatures, rainfall and vegetation.

The long-standing view among ecologists has been that mountainous areas act as refuges for species that have been driven out of their normal habitat by difficult environmental conditions.

A typical example could be a species dwelling in plains near the base of mountains - a change in conditions on the plains might mean that mountain areas begin to suit the needs of the species better, causing it to migrate.

"We had never thought of mountains as the birthplaces of species before," said Russell Graham, a palaeoecologist at Pennsylvania State University in University Park.

"Mountains have always been considered the places for species to make their last stands because they offer such diverse terrain," he added.

Curious about the mechanisms responsible for making mountains so rich in diversity, Badgley and her collaborator John Finarelli, also at the University of Michigan, studied mountain and lowland speciation rates and species richness using the fossil record of the Rocky Mountains and the Great Plains in North America.

The fossils they inspected date to the Miocene period, which began around 23 million years ago and ended about 5 million years ago.

They found that there were bursts of speciation that took place only in the mountains during times of tectonic activity.

During all other times, they discovered that speciation rates in the two regions were moderate and similar.

Badgely and Finarelli now propose that as mountains are lifted up by the tectonic processes of the Earth's crust, mountain-dwelling species become isolated from other members of the same species living at lower altitudes.

This isolation ultimately leads to the two groups breaking apart to form individual species.(ANI)