Kingdom. Phylum. Class. Order. Family. Genus. Species. In a text book, life is well defined-- an assemblage of discrete, static vessels-- stuffed, pinned and labeled.
An organism appears as a sum of its evolutionary parts. Its identity and natural history-- reduced and confined within a dichotomous key. Life, through this lens is rigid and known, and stale.
It's exciting to think however, that the titles assigned to specific organisms can equally be viewed as artificial constructs-- created by a scientist for reference and categorization but ineffective at conveying a deeper biological meaning. Perhaps names and definitions aren't inextricably linked-- inherent to an organism. If the taxonomic labels; the 'species' and 'sub-species' qualifications attached to an individual don't hold water genetically then what's to be said of our ontological understanding of what a species actually is?
. . . The team has been careful not to call Denisovans a new species, opting instead to label them as a Neanderthal "sister group." If modern humans and Denisovan humans were separate species, their hybrid children probably wouldn't have been able to reproduce. But the hybrids apparently were able to have babies, otherwise the Denisovan DNA couldn't have been passed down to today's Papua New Guineans. Therefore, study co-author Viola reasoned, Denisovans and modern humans probably weren't separate species.
Scientifically, though, it matters little whether Denisovan is ultimately recognized as a new species, said Terry Brown, a geneticist at the University of Manchester in the U.K., who wasn't involved in the study.
"This whole species thing is a red herring, something that makes a nice headline but does not in my view contribute much to the scientific debate," Brown said in an email. "We really don't know how to equate differences in genome sequences with the species concept," he said. "You could have two genuine species, whose members cannot interbreed, but whose genomes are very similar. "So really the nuclear DNA does not help us decide if Denisovans are a new species, though the evidence for interbreeding with modern humans suggests they are not.
