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Read out Roses, tulips, carnations ... - in terms of their biodiversity, the flowering plants are the most successful group in the realm of botany. Fossil finds prove that this triumphal procession began in the early Cretaceous period: on an evolutionary scale, the flowering plants produced an enormous biodiversity in a very short time. This steep career surprised even the founder of evolution, Charles Darwin: He called it a mystery. It has already been suggested that the rapid increase in biodiversity was based on interactions between the evolution of plants and pollinating insects. Special importance was attributed to bee species in particular. This theory is now supporting the findings of US researchers Sophie Cardinal and Bryan Danforth of Cornell University in Ithaca. While the developmental history of the so-called Bedecktsamer is well documented by findings, the roots of the pedigree of today's bees in the dark millions of years lose, because there is hardly any fossil record, the Provide insights into early stages of development of this insect group.

Genetics reveals the roots of the bee tree

That's why Cardinal and Danforth have chosen an alternative method to look at the roots of bees' pedigrees: genetics. They collected molecular genetic data from a total of 152 bee species living today. To find out when the ancestors of these different species diverge, they analyzed the mutation rate of certain genes. So they used this information as a sort of molecular clock indicating evolutionary developments.

The evaluations and complex mathematical models suggested that the stem forms of the bees originated about 123 million years ago. Exactly at this time, the flowering plants developed into a green power, emphasize the researchers. Microfossils of their pollen appear for the first time in about 125 million years old rock layers, explain Cardinal and Danforth. display

The relationship of flowering plants and bees is a prime example of so-called coevolution, the researchers say. 78 to 94 percent of all Bedecktsamer be pollinated by animals, especially of bee species. In return for this service, the plants provide their pollinators with food. This relationship literally drove many different flowers: more and more finely tuned combinations of plant and bee species were created. It was also from the point of view of evolution to a very fruitful relationship.

Sophie Cardinal and Bryan Danforth (Cornell University, Ithac) et al .: Proceedings of the Royal Society B, doi: 10.1098 / rspb.2012.2686 © science.de - Martin Vieweg

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