Thursday, April 02, 2015

Chinese reseacher reveals cause for sudden diversification of species

Palaeontologists around the world have been searching for centuries for the answer to what caused the sudden diversification of species on earth at the beginning of the Cambrian Period. The search recently came to a close when a German-based Chinese researcher, Lin Na, found the reason has to do with niche formation and tectonic plate movements.

About 540 million years ago, an event known as the Cambrian explosion took place which had a major influence on the evolution of life on earth, as countless new species evolved almost simultaneously within a short period of time, becoming the predecessors of today's main animal groups.

In order to find out what caused this event, researchers at the Friedrich-Alexander University of Erlangen-Nuremberg (FAU) evaluated a large database of fossils from the Cambrian Period and analyzed the biological diversity of all known species from this period on a local, regional and global level with the aim of understanding the ecological principles that led to the Cambrian explosion.

Their findings have recently been published in the US journal Proceedings of the National Academy of Sciences.

According to Lin, from FAU's Chair of Palaeoenvironmental Studies, the different evolution of different populations played a much more important role than the increased number of species within local ecosystems in the early Cambrian Period.

As species adapted more and more to their environment, their ecological niches became more restricted, which means that individual populations evolved into new species that were adapted to their environments.

Meanwhile, carnivores also played an important role in this, as Prof. Wolfgang Kiessling, Chair of Palaeoenvironmental Studies, explained.

"Carnivores kept populations small, preventing too much competition for resources. At the same time, however, they forced species to develop new ways of avoiding being eaten and increasingly sophisticated methods of getting food."

However, as the research uncovered, on a global level there was another factor driving the evolution of species forward: plate tectonics.

At the beginning of the Cambrian Period, the super-continent Pannotia broke apart. From then on, deep oceans separated parts of the land and the different sea creatures evolved separately.

"We saw a significant increase in provincialism. The species composition found in the continents' different old shelf seas became more and more different. This could be the main reason that the total number of species increased so considerably," said Lin.


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