Tuesday, November 30, 2010

Forest collapse boosted reptiles

Carboniferous forestThe coal forests covered Europe and North America during the Carboniferous
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The fragmentation of tropical rainforests 300 million years ago helped pave the way for the rise of the dinosaurs, a new study suggests.

In the Carboniferous period, North America and Europe lay at the equator and were covered by steamy rainforest.

Global warming is thought to have brought about the collapse of these tropical habitats, triggering an evolutionary burst among reptiles.

The work, by a British team, is published in the journal Geology.

The forests that covered the ancient supercontinent of Euramerica are colloquially referred to as the Coal Forests.

Fossil reptile - Spencer Lucas, New Mexico Museum of Natural HistoryThe team used fossils to track the course of reptile evolution

They are so called because they accumulated a large amount of peat, which later turned into the coal that is mined today.

Towards the end of the Carboniferous, the Earth's climate is thought to have grown hotter and drier.

"Climate change caused rainforests to fragment into small 'islands' of forest," said co-author Howard Falcon-Lang, from Royal Holloway, University of London.

Dr Falcon-Lang continued: "This isolated populations of reptiles, and each community evolved in separate directions, leading to an increase in diversity."

To reach their conclusions, the scientists studied the fossil record of reptiles before and after the collapse of the rainforests.

Dimetrodon (SPL)Reptiles diversified into forms such as Dimetrodon, a top predator in Permian times

They showed that reptiles became more diverse and even changed their diets as they struggled to adapt to a rapidly changing climate and environment.

Professor Mike Benton, from the University of Bristol, said: "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."

His Bristol colleague Sarda Sahney commented: "It is fascinating that even in the face of devastating ecosystem-collapse, animals may continue to diversify."

Paul.Rincon-INTERNET@bbc.co.uk

This article is from the BBC News website. � British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.

Source: http://www.bbc.co.uk/go/rss/int/news/-/news/science-environment-11870322

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