New Genetic Motion of the Ocean Discovered

Currents aren't the only thing flowing across the oceans - recent research shows that genetic cargoes move far faster than previously thought.

The rise of new species on land is largely due to allopatric speciation, where things find themselves cut off from their parent populations and gradually adapt on their own.  The isolation is essential to allow evolution, otherwise constant mixing with unaltered examples of the species would water down any changes which occur.  The most dramatic example of this is Australia, which evolved an entirely independent ecology - until settlers enable invasive species to cross the previously impenetrable barrier.

Many believe that the different oceans, with their varied conditions, provide similarly separated "continents" for cellular sea-life like plankton, which is unable to swim against the currents. But this approach seems to ignore the facts of diffusion and how plankton are alive - only a few need to make it to set up a new population.

Now, oceanographers of the Scripps Oceanography institute have shown that plankton aren't as cut off as previously thought.  Examining some (extremely small) fossils, they've shown that Truncorotalia Truncatulinoides plankton have repeatedly crossed from the Pacific to Atlantic oceans over a time they were thought to be physically blocked, 2 to 2.8 million years ago.  Further, such invasions coincided with climate variations - indicating that making the trip was never the problem, just surviving once they got there.

This freedom of movement suggests that ocean isolation was never the driving factor in speciation, which was instead sympatric, with different variations able to exist in the same locations while preserving their genetic identity.  The "They all spontaneously appeared, fossils and all, six thousand years ago" option remains strangely undiscussed by the Scripps scientists.

Posted by Luke McKinney.

Ocean Organism Origins http://www.sciencedaily.com/releases/2008/12/081231175357.htm