Critics of evolution have always maintained that mutations and selection can only produce new varieties inside a certain species, that one could not have new species emerging via such a process. This idea has finally been empirically rebutted: scientists have now observed the actual emergence of new species.

In fact the discovery also came as a surprise to them. Grace Wyngaard, a biologist at James Madison University, and colleagues Andrey Grishanin of the Russian Academy of Sciences, Ellen Rasch of East Tennessee State University and Stanley Dodson of the University of Wisconsin-Madison thought they were studying a single species of plankton, called copepod, when they noticed that they were actually looking at a collection of many species that were not interbreeding. These species of plankton are changing at such an unusually high rate that one can observe not only the variation of individuals inside the species, but the actual emergence of new species.

The copepods are microscopic crustaceans inhabiting lakes, ponds, rivers and ditches, and serve as the main diet for many fish.

"Some identically appearing forms collected from the same pond cannot mate and produce young, thus defining them as different species," said Wyngaard. "By following the parents and offspring of these plankton in the laboratory, we discovered that they reorganize their DNA dramatically from one generation to the next."

The issue here is how these creatures can allow such a large genetic variability without succumbing to great number of damaging mutations. Wyngaard and her colleagues argue that they probably have very interestingly organized genomes that allow new, and sometimes successful, combinations of genes to arise quickly.

Photo Credit: Wim van Egmond