From Geoffrey E. Hill at The Scientist:
What defines a species? Because the boundaries between species can appear so fluid, pursuing such a question seems, at times, like academic esoterica—little different than discussing how many angels can dance on the head of a pin. But accurate species definitions lie at the heart of biological investigations and management of natural resources (e.g., the US Endangered Species Act). It is troublesome, therefore, that new information on the genetic structure of long-recognized species of birds could jeopardize their status as full species.
The problem, in a nutshell, is that the DNA of many familiar species of birds holds signatures of substantial exchange of nuclear genes with other bird species. Such gene exchange matters because, by decades-old definitions, it is the isolation of gene pools that defines species. Substantial genetic exchange raises questions about whether these populations truly constitute species.
A case-in-point concerns the blue- and golden-winged warblers, two beautiful and very distinctive little songbirds that have long been regarded as separate species. A recent study, however, showed that these two “species” share more than 99 percent of their nuclear genes—much more gene sharing that we would expect between full species. More.
However, their mitochondrial genes are characteristic of separate species.
Idea! Use the money currently allotted to “Selling Darwinism to a Wary Public” to fund a re-examination of how we determine the boundaries of life forms instead.
See also: Big squawks over bird speciation?
Nothing says “Darwin snob” like indifference to the mess that the entire concept of speciation is in
Follow UD News at Twitter!