for Javasaurus, who's asked about this...

[acroyear]

Evolving Thoughts: What is a species?:

If somebody asked me to write a short essay giving an overview of my favourite topic, the nature of species, I doubt that I could. I can write a long essay on it (in fact, several) but it would be excruciatingly hard to write a short one. For that, we need a real writer. Carl Zimmer is the guy. He has an essay on species in the current edition of Scientific American. And despite quoting some obscure Australian philosopher, it is a good summary of the issues. How he manages to get up on a topic like that amazes me. It took me a good five years.

Comments

[javasaurus.livejournal.com]

Thank you! Of course, now I'll be thinking about this for the rest of the day, instead of doing my job...

Good article for stirring the brain cells a bit. It induced me to seek out the (rather lengthy) Wikipedia article (click here) for even more info on the current state of affairs. Some of it mimics the article you linked, and it also includes the following quote from Darwin, which is similar to some of the ideas in the science blog article:

I look at the term species as one arbitrarily given for the sake of convenience to a set of individuals closely resembling each other .... it does not essentially differ from the term variety, which is given to less distinct and more fluxtuating forms. The term variety, again in comparison with mere individual difference, is also applied arbitrarily, and for mere convenience sake.

After reading these, I'm more inclined to think of "species" as a designation of dis-similarity, rather than similarity. We can say that a walrus is not a rose bush, that they are significantly far apart in the species continuum, while tigers and lions are relatively close, so maybe we're not sure if they are different species. Maybe it should be like statistics, and we could assign p values to the probability of "not the same species." But this, too, gets back to the article which indicates our desire to somehow quantitate speciation.