Evolving Thoughts

Evolution, culture, philosophy and chocolate! John Wilkins' continuing struggle to come to terms with impermanence... "Humanus sum, nihil humanum a me alienum puto" - Terence

Wednesday, September 28, 2005

Species concepts are too important

So, now that the Book is in the hands of the publishers (we wait with breathless anticipation), it pleases me enormously that this paper shows how differing species concepts affect the ways in which conservation biology is to be undertaken.

Comparing the biospecies concept of Ernst Mayr and more recently Jerry Coyne and Allen Orr in their book Speciation, with the more recent phylospecies concept (actually there are a lot of things that go by this name; here the authors are considering what I call the Autapomorphic Species Concept, where a species is a terminal node in a cladogram, specified by their autapomorphies, or uniquely derived traits), Shaun Dillon and Jon Fjeldsa of the Zoology Department of the University of Copenhagen examined how each conception affected the measures of biodiversity of the entire bird fauna of sub-Saharan Africa.

The result is that diversity is pretty well fractal - although the phylospecies concept has caused what some worry is a kind of taxonomic inflation, both concepts uncover the same areas of richness and paucity. Since any diagnostic difference will give you a phylospecies, phylospeciesists tend to be splitters, while biospeciesists tend to be lumpers (but not too lumpy - they will still identify as "good" species parts of species complexes that will occasionally hybridise).

It's an interesting paper, and they use an amazing tool - WORLDMAP - devised by Paul Williams and his colleagues at the Natural History Museum in London.

[I wish they'd tried to operationalise a few other species concepts, too. There are around 25 of the buggers.]