Do species “learn” their way into existence?

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <table border="0" cellpadding="0" cellspacing="0" width="95%" height="1"> <tr> <center> <td valign="top" width="33%" height="33"> <p class="MsoNormal"><b><font face="Arial" size="5">Do species “learn” their way into existence?</font></b></p> <p class="MsoNormal"><font size="1"> July 2, 2005<br> Special to World Science </font> <b><font face="Arial" size="2"><br> <br> An old puzzle for biologists has been how one type of organism evolves into two—a branching process that seems to be nature’s chief way of producing new species.<br> <br> Researchers say they have devised at least a partial explanation: species can to some extent learn their way into existence, by colonizing new habitats and then learning to exploit them.  </font></b> </p> <p class="MsoNormal"> <b><font face="Arial" size="2"> That would help break populations into genetically isolated groups that can evolve into separate species with relative ease.<br> <br> “Learning promotes speciation,” or the rise of new species, wrote Joost Beltman and Johan A.J. Metz in the July 22 issue of <i> Proceedings: Biological Sciences</i>, a research journal of the Royal Society of London. The researchers are with Leiden University in Leiden, the Netherlands.<br> <br> The findings so far are based only on mathematical calculations, but the researchers say they could help untangle a knot that has long snarled up part of evolutionary theory.<br> <br> The theory of evolution holds that new species arise through random mutations, which either harm or help the organisms they strike. When a mutation is helpful, the affected creature and its genes spread widely at the expense of others, gradually changing a population’s characteristics and eventually spawning new species.<br> <br> While that’s believed to explain how an entire population may change, it doesn’t clarify how it can break up into separate species. <br> <br> If a population is split up by a permanent physical barrier such as a river, this question is easy: each population can evolve its separate ways. But if there is no such barrier, constant mating among members of the population tend to mix up the gene pool and block the process.<br> <br> Biologists have long struggled to explain why this seems to happen anyway.  </font></b> </p> <p class="MsoNormal"><b><font face="Arial" size="2">Various proposals have come up, but most are generally considered partial solutions at best. One idea popular among scientists is that organisms prefer to mate with those most like them, preventing random mixing. But this assumes some genetic separation has already occurred, raising a chicken-and-egg problem.  </font></b> </p> <p class="MsoNormal"> <b><font face="Arial" size="2">Researchers are exploring different mechanisms that could help break this loop.  </font></b> </p> <p class="MsoNormal"> <b><font face="Arial" size="2">For instance, one study found that some newly diverged butterfly species have unusually obvious coloration differences. This could help their members distinguish each other and keep them from mixing back into one species. That study appeared in the July 21 issue of the research journal <i>Nature.</i> <br> <br> But another possible mechanism that could break the chicken-and-egg loop could be the learning process, Beltman and colleagues argue.<br> <br> Many animals, including fish, insects and birds tend to prefer to live where they grew up, wrote Beltman and Patsy Haccou, also of Leiden University, in a paper in the May issue of the journal <i> Theoretical Population Biology</i>.<br> <br> Thus, “females normally produce their young in the same habitat as they grew up in,” they wrote. “They may, however, accidentally produce their young in another habitat.”  </font></b> </p> <p class="MsoNormal"><b><font face="Arial" size="2">Moreover, “ The young resulting from ‘accidents’ will learn features of the new habitat. Because of this, they will most likely mate with other individuals exploiting the habitat, and adult females will tend to produce their young in the new habitat.”<br> <br> “Through such processes, the colonization of a new habitat may eventually lead to speciation.”<br> <br> * * *</font> </p> <p><font face="Arial" size="2" color="#FFFFFF">Send us a <a href="mailto:editor@world-science.net">comment</a> on this story, or <a href="mailto:?Body=http://www.world-science.net/exclusives/050806_learnfrm.htm">send it to a friend</a></font> </p> </b> </center> <p>  </td> </tr> </table> </body>