November 30, 2010

Rainforest Collapse Helped Give Rise To Dinosaurs

The loss of tropical rainforests some 300 million years ago led to evolutionary changes in reptiles that ultimately resulted in the rise of the dinosaurs, claims a new study recently published in Geology, a journal of the Geological Society of America (GSA).

According to scientists, the event which gave rise to the dinosaurs occurred during the Carboniferous Period. At that time, they say, Europe and North America were one continent and covered by tropical rainforests. As the Earth's climate began to become hotter and drier, the rainforests began to fade away, and reptiles were forced to adapt to survive.

"Climate change caused rainforests to fragment into small 'islands' of forest," study co-author Dr. Howard Falcon-Lang, a member of the University of London's Department of Earth Sciences, said in a statement on Monday. "This isolated populations of reptiles and each community evolved in separate directions, leading to an increase in diversity."

"This is a classic ecological response to habitat fragmentation," added Bristol University Professor Mike Benton. "You see the same process happening today whenever a group of animals becomes isolated from its parent population. It's been studied on traffic islands between major road systems or, as Charles Darwin famously observed in the Galapagos, on oceanic islands."

The British scientists came to their conclusions after studying the fossil records of reptiles from both before and after the collapse of the ancient rainforests. The fossils illustrated a growing diversity over time, and even revealed that the lizards altered their diets in order to survive in their ever-changing conditions, both in terms of temperature and landscape.

According to Benton's Bristol University Colleague Sarda Sahney, the study shows that "even in the face of devastating ecosystem-collapse, animals may continue to diversify through the creation of endemic populations." But, she warns, "Life may not be so lucky again in the future, should the Amazon rainforest collapse."


Image Caption: The scientists studied fossils, like that of the Sphenacodon, for their report. Courtesy Wikipedia


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