Greater Diversity of Life in Tropics


In past centuries explorers found that the further you go from the tropics, the fewer different kinds of life there are. The question became, is it because more species originated in the tropics or because older ones can persist there longer?
A team of paleontologists who studied a large group marine animal recently gave the answer: it’s both.
About three-quarters of today’s types of these creatures originated in tropics and spread toward the poles, while only one-quarter originated at higher latitudes.
As they traced the marine animals back in time, the researchers found that only 30 varieties had lived in tropics went extinct in past 11 million years, while 107 outside the tropics died out.
“The tropics are the engine for global biodiversity,” said co-author Kaustuv Roy. “What this means is that human-caused extinction in tropics will eventually start to affect the biological diversity in the temperate and high latitudes.”

Jin Yanni

(Resource: http://www.enn.com/today.html?id=11396)