Wednesday, December 01, 2010

Rainforest Collapse Triggered Carboniferous Reptile Evolution

Rainforest collapse triggered Carboniferous tetrapod diversification in Euramerica. 2010. S. Sahney, et al. Geology 38: 1079-1082

Global warming devastated tropical rainforests 300 million years ago. Now scientists report the unexpected discovery that this event triggered an evolutionary burst among reptiles -- and inadvertently paved the way for the rise of dinosaurs, 100 million years later.
This event happened during the Carboniferous Period. At that time, Europe and North America lay on the equator and were covered by steamy tropical rainforests. But when the Earth's climate became hotter and drier, rainforests collapsed and fragmented into small 'islands' of forest. This isolated populations of reptiles and each community evolved in a separate direction, leading to an increase in diversity."

Mike Benton of the University of Bristol added: "This is a classic ecological response to habitat fragmentation. 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."

To reach their conclusions, the scientists studied the fossil record of reptiles before and after rainforest collapse. They showed that reptiles became more diverse and even changed their diet as they struggled to adapt to rapidly changing climate and environment. link