A new species of finch has appeared on a Galapagos Island (1 Viewer)

Fascinating stuff:

http://www.wired.com/wiredscience/2009/11/speciation-in-action/?npu=1&mbid=yhp


The work and dedication by this couple is nothing short of amazing.

D.

There must be something wrong with the labelling of photos A to F.

And is there really a new species?

Steve

Its a very interesting study, but I think they are jumping the gun a bit in claiming a new species. At best it shows how speciation could potentially occur, but the whole thing could easily be messed up by a repeat of what happened originally - a Medium Ground-Finch flying to the island and mixing with these hybrids. It happened once before, so why should it not happen again?

Tom

Yes, pictures E and F show birds with very different bill sizes. Something was wrong here.

To make sure: this is a case example how a new species may appear. However, it could easily wiggle the other way (population becomes extinct or hybridizes back).

Lovers of splitting Scottish Crossbill and other crossbill taxa might notice, that it took only a few years and three generations to create something similar to crossbill races (geneticaly identical, distinctive call, assortative breeding)!

The Grant paper is well worth a look and reads differently than the pop version on wiredscience. As per Jurek's second paragraph, the Grants are not claiming a new species but use wording such as: "These observations provide important insight into the process of speciation at the beginning of the sympatric phase following divergence in allopatry" and pose questions such as how many generations of allopatric isolation are needed to constitute a species.

Wiredscience took the photos from the paper and got the labelling wrong.

http://www.pnas.org/content/early/2009/11/12/0911761106.full.pdf

(I don't know if you need to be a subscriber to open this link).

Thanks for the link John. I was able to get access to the paper without a subscription.

Tom

jurek said:

Lovers of splitting Scottish Crossbill and other crossbill taxa might notice, that it took only a few years and three generations to create something similar to crossbill races (geneticaly identical, distinctive call, assortative breeding)!

Click to expand...

Not sure if I qualify as a lover of splitting Scottish Crossbill That is possibly the case with the various 'types' of curvirostra, and may even explain why we keep discovering 'new' crossbill calls and why these 'types' breed assortatively. However, as stated previously the various Loxia 'species' are not strictly genetically identical, though agreed the differences are slight. More interestingly, from what you say, it may explain why some call types appear to 'extinct'........

The problem is that the extent or effects of hybirdisation with crossbills is virtually impossible to determine or measure in the field, even with mass colour ringing of adults and progeny - the various 'species' appear to have large overlaps in their morphology (particularly bill size) and can sychronize or learn calls, so what we are left with is various behavioural and ecological factors. In this respect, I agree with you that genetics is the only quantatitive method for assessing possible hybridisation or at least measuring any temporal changes that may occur within a population ( if we can't genetically determine or quantify a 'species' in the first place !). But that will involve seriously large amounts of data collection and analysis and I am not aware of anyone undertaking that, or who will. Crossbills are quite difficult to catch, so unless we go back to 'collecting' them.........

Yes, this paper does seem to have some relevance for crossbill researchers !

....anyone know where to get a freebie copy or preview of this paper ?

Yes, I know Peter Grant's paper was more cautious that media blurb.

BTW - this shows again that bird species are NOT panmictic, that is you get groups, subpopulations, social classes ( ) which prefer mating with each other.

Curiously, I don't remember a good overview of this topic. I recall only snippets of information, like that urban and woodland Blackbirds don't interbreed and that humble Feral Pigeons prefer to mate with similar looking individuals.

That is why I pay such attention to the DNA - DNA difference is a clear proof that populations are not interbreeding for a long time, something which cannot be checked during few years of a typical field study.