Wilkins Replies

Wilkins has replied to my post on species concepts.

The gist: there are a bunch of species concepts, many of which are pretty darn good.

My reply: that's awesome as long as they guide future research. The BSC provides a framework for studying reproductive isolation. Ecological species concepts are useful when studying adaptation to niches. But I still see nothing interesting that can be garnered from purely phylogenetic- or divergence-based species concepts.

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RPM says,

My reply: that's awesome as long as they guide future research. The BSC provides a framework for studying reproductive isolation. Ecological species concepts are useful when studying adaptation to niches. But I still see nothing interesting that can be garnered from purely phylogenetic- or divergence-based species concepts.

This doesn't sound very scientific. Do you realize what you're implying?

You seem to be saying that you don't care what the true meaning of species is. You're willing to live with a "false" notion of species as long as it drives research.

That's a very bizarre position. Let's assume for a moment that the best definition of species is the phylogenetic one, does that mean all research on species will come to an end or only the research that's been based on the false definition?

I'm saying all species concepts are artificial -- just like any other taxonomic category.

Rather than trying to find a species concept that works for every taxon, it's better to pick a concept of species that fits the particular question you're studying.

In practice, one doesn't even need to think of species or species concepts, but the terms are ubiquitous and won't go away. For instance, you can study the evolution of reproductive isolation (whatever form you fancy) without calling it speciation. The same goes for studying the evolution of niche differentiation.

But people will continue to use the term speciation, so we might as well acknowledge that what passes as species/speciation in one taxon may be different from that in another taxon. And if people will continue to study speciation, they might as well use a species concept that fits what they are calling speciation.

Defining species based on some measure of divergence may work well across multiple taxa, but what does it tell us about speciation (however you'd like to define it)? As taxonomically limited as the BSC is, it has led to lots of interesting work on reproductive isolation.

BSC = Biological Species Concept. It basically states that speciation has ocurred when the proto-species can no longer produce viable offspring.

Rather, when the likelihood is very much reduced.

I hold a view that phylogenetics must break down at some point, where reticulation overpowers the phylogenetic signal (and this will be different for different organisms). So in terms of speciation, the phylospecies are not helpful, as they presuppose bifurcation rather than explain it. That's not a fault of phylogenetics, but a precondition for doing it.

However, reciprocal monophyly is a useful research guide, in that it can tell us about the past structure of a species lineages to some extent.

Personally, I don't think there is such a thing as a phylospecies conception. It's all either morphological (including molecular sequence "morphology"), reproductive, or some other surrogate for "specieshood".