Image of the Day: Plankton-A-Plenty

Tiny plankton living in the same pond and previously thought to be one species in fact are several, a new study finds.

Researchers are surprised how quickly the plankton, called copepod, forms new species.

"This study provides critical evidence that the ways species form and evolve are more complicated than we had previously understood," said Sam Scheiner, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research.

Copepods are microscopic crustaceans found in lakes, ponds, rivers and ditches. They're 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 the study's lead researcher, Grace Wyngaard, a biologist at James Madison University. "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 results, announced yesterday, are detailed in the journal Evolution.

--LiveScience Staff

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Credit:  Wisconsin A. Vernalis