Groundwater may have helped ancestors to thrive, evolve

Washington: A new study has revealed that the ability to find the new groundwater sources during extremely dry periods in Africa millions of years ago may have helped ancient ancestors to survive and evolve as species.

The research combined the geological evidence from the Olduvai sedimentary basin in Northern Tanzania, which formed about 2.2 million years ago, and results from a hydrological model.

It showed that while water in rivers and lakes would have disappeared as the climate changed due to variations in the Earth's orbit, freshwater springs fed by groundwater could have stayed active for up to 1000 years without rainfall.

Potable water in rivers or lakes in the region was likely to have been scarce, owing to salinity, drought and the short-lived flow of streams. Groundwater might have provided "a key alternative potable resource for sustaining life" in the environment.

Such groundwater refugia might have been sites for intense competition between hominin and other animal species and hence selective pressure favoring those who could maintain access to water, something for which there was no substitute.

Professor Gail Ashley, Rutgers University (US), said that furthermore they speculated that, during wetter periods, springs might have formed ways of 'bridging' longitudinal dispersal of hominins between larger freshwater bodies or rivers providing a critical resource during hominin migration within and out of Africa.

The research is published in the journal PLOS ONE.