The islands were vital workshops to promote evolutionary theory from the pioneering work of Charles Darwin and Alfred Russel Wallace in the 19th century.
Now, a new document appears at PLOS ONE by an international team of researchers, describes two new Mars' mineral relatives who shed light on how a unique island ecosystem evolved 43 million years ago during Eocene.
"Evolution in many ways is easier to study in an island context than on a large continent like North America because it is a simpler ecosystem," said colleague K. Christopher Beard, Professor of Ecology and Evolutionary Biology at the University of Kansas, editing the KU Institute of Biodiversity and the Natural History Museum. "Evolutionary biologists have focused on islands since Darwin and Wallace independently developed their ideas for evolution based on their observations on the plants and animals living in the Galapagos and the Malay archipelago,
However, Beard has said that a poor historical fossil for animals living on islands through a "deep period" or over a multi-million-year period has hampered our understanding of exactly how island islands are assembled. The new paper describes two new fossil species, identified by their teeth, who lived in the Pontius region of modern northeastern Turkey.
During the Eocene region the Pontide was an island in a larger version of the modern Mediterranean Sea called Tethys. At that time, Africa and Eurasia were not connected as they are in the Middle East, but Africa drifts northward because of the tectonic plate and eventually collides with Eurasia millions of years later. The Pontius area was among these converging continents. This geological environment makes the Pontius region similar to the island of Sulawesi on the ancient island of Indonesia, which is similar between the converging continents of Asia and Australia.
"No other ecosystem on the face of the globe from any time period matches what we found in Turkey's Eocene – it's an entirely unique mammalian ecosystem, as it is today Madagascar," he said. "But how did this biotic island develop over time? You need fossils and time to see this, we can study here in great detail how this ancient island evolved – where the different animals came from when they arrived there. After arriving there, some of these mammals, including one of the new rows of worms we discovered, were able to differentiate on the island. Most Eocene mammals on the island of Pontide seem to have gone there swimming or rafting beyond me the Thaci rather than lost when the island was separated from the adjacent parts of Eurasia. "
Beard's collaborators in the research were Grégoire Métais of the National Museum of History in Paris, John R. Kappelman of the University of Texas, Alexis Licht of the University of Washington, Faruk Ocakoglu of the Eskis ehir Osmangazi University in Turkey, and Pauline MC by KU Coster and Michael H. Taylor.
In the fossilized Pontide fossils – which have no living offspring – the group has found signs that the distinct forms of life that develop on the islands are generally inadequate as they have plenty of time.
"One thing we know is that the incredibly interesting and unique Eocene biotom that happened on this island in what is now Turkey at some point was completely eliminated," said Beard. "It was eliminated when the island was reconnected to mainland Eurasia and more cosmopolitan animals could obtain it for the first time, leading the strange biotic island to extinction." The message of conservation biology today is that island ecosystems are inherently ephemeral in the great The ugly truth that palaeontology provides is that, as long as many times, most island faunas are doomed to disappear and are a dead end of evolution – – although they are wonderful places to the processes of evolution. "
Beard said the two recently described mineral marsupials – Galatiadelphys minor and Orhaniyeia nauta – lived near the top of the Eocene Pontide food chain because carnivores could not reach the small island.
"One of the strangest things about the island's fauna than the Pontians is that there are no real carnivorous mammals," he said. "There was nothing to do with cats, dogs, bears or ferrets – there were no modern mammalian predators, they could not get to Pontide's territory because it was a small island, a food chain."
According to the KU researcher, the newly discovered fossils show that the geological context has a tremendous impact on how the ecosystems are assembled on a given island.
"The current ideas for the island's development are based on some simple, yet fairly effective models," said Beard. "These models suggest that the islands colonize the islands based on two key factors – how big is the island and how far away it is from nearby continental land areas? A larger island is targeting and hosting a larger variety of habitats, facilitating organizations to colonize island and once they get there, they are more likely to survive and perhaps even diversify. "
Based on the findings of his team from Pontius, Beard reported that the geological framework was at least as important as the size or distance of an island from the area of animal colony origin.
"All men may have been created equal, but all the islands were not." The geological context of the island – here is in an area of active tectonic convergence – we believe it floods other factors, size and distance from the mainland, "he said. "The most odd thing about mammalian fauna is that it contains a unique mixture of animals from Europe, Africa and Asia, even our two new marsupials exhibiting different evolutionary roots in the North and the South. Eurasia and Africa and the animals arrive there in many directions. We can make an interesting analogy with the modern island of Sulawesi in Indonesia, which like the Pontian soil has a mixed fauna and hosts mainly animals such as tarsores, sardines which are clearly associated with Asian species, but you also have the Sulawesi species that are apparently associated with mammals from New Guinea.If you look at the tectonic plate today, Sulawesi is becoming close between Australia and Asia in the same way that Pontide was housed between Africa and Asia in Eocene. "
Beard recently returned from Turkey, where he and his team conducted more research in the field. This research has been funded from multiple sources, including a large grant from the US National Science Foundation.