"For example, why are there so many insect species? Speciation cascades provide one explanation for how a lot of species might be generated in a relatively short time period. In addition, it is not irrelevant that geographic barriers appear not to have been directly involved in species divergence in this case," Smith said.
Evolutionary divergence, he explained, tends to be associated with geographic isolation.
If fruit flies don't make an impressive example of speciation and environmental adaptation, the researchers noted, consider that more than half of all animals could be considered parasites in a broad sense, that plant-eating insects outnumber all other life forms and that one-fifth of all insects could be parasitic wasps. The conclusion, they wrote, is that "there is a world of opportunity for sequential speciation in nature."
"Clues can be found right before us as we sit on our deck chairs barbecuing and drinking pop," principal investigator Jeff Feder told Science. "All we have to do is open our eyes and we can see new life forms coming into being in that scraggly old apple tree in our backyard."
|Contact: James J. Smith|
Michigan State University