What is a species? (1 Viewer)

[Andy Adcock]

This is different to my arguement - I was suggesting that when in doubt, air on the side of caution (and of most advantage to species conservation). An example (I think) is Balem Currasow, which I seem to recall is not considered a species by Clements and IOC, but is considered a Critically Endangered species by BirdLife International. If there is any doubt, surely the safe option would be for IOC and Clements to roll over and follow BirdLife International - not to adopt their own status quo.

Safe politically?

I have no issue with species conservation, just to add.

 

[Mysticete]

I don't work on birds of course, but my experience has been similar with working on other taxonomic groups. There is a serious concern in fact, at least amongst marine mammal biologists, that the lack of incentive for pursuing this line of research is resulting in few people actually having the expertise to assess these sort of questions.

 

[Paul Clapham]

You could try reading Jerry Coyne and Allen Orr's book "Speciation". Executive summary: there's about 20 different ways that scientists classify species. Fortunately (for us here) there's only 2 or 3 which are used by ornithologists, and BSC is leading the pack.

Probably others in the thread have said something like this, but here's how I see it: at time X there's a group of birds which are freely interbreeding. A million years later, due to various external influences, there's two groups which breed freely within the groups but not between the groups. So speciation has occurred. But during that million years it's been confusing, both for us and for the birds. Hybrids may or may not have been produced, depending on what those external influences were.

But there's no instant during those million years when we can say "Then! That's when it happened!" There's only a long grey area when it happened. This implies that we are in that long grey area for many speciating groups. But we expect the working scientists to provide a yes-or-no answer when it's really not possible to do that, which results in the discussions which you can see in the literature.

(It's actually more complicated than that. But I think this is a reasonably good overview.)

 

[Melanie]

Interesting is that you find merely species in the paleontological account but rarely subspecies. So a bird bone from the Cretaceous has only a little information whether it is a species or a subspecies.

 

[njlarsen]

Interesting is that you find merely species in the paleontological account but rarely subspecies. So a bird bone from the Cretaceous has only a little information whether it is a species or a subspecies.

Would you be able to separate unequivocally the different warblers by finding just 1-5 bones? (It does not really matter if you think about separating members of the American Wood Warblers or members of genus Phylloscopus). I doubt it would be possible but I do not know. But my expectation is that for reasons like this, the biodiversity in those ancient times are likely to be underestimated.
Niels

 

[jurek]

I know I have replied to this argument of yours multiple of times in various threads, but I will keep replying: The idea that scientists only are interested in splitting species to get more papers is silly. Unless your species is some sort of big charismatic species like an elephant or giraffe, a taxonomic change such as a split will never get published in any high impact journal.

I think you are constructing a straw man argument here, suggesting that this is the only reason, or that science misconduct must be done in high ranking journals only. Precisely because taxonomy is relatively obscure, there is an incentive for scientists to spice up papers by suggesting splitting species.

Incentive to split is known enough to get names like oversplitting or taxonomic inflation, and certainly real.

 

[Mysticete]

I think you are constructing a straw man argument here, suggesting that this is the only reason, or that science misconduct must be done in high ranking journals only. Precisely because taxonomy is relatively obscure, there is an incentive for scientists to spice up papers by suggesting splitting species.

Incentive to split is known enough to get names like oversplitting or taxonomic inflation, and certainly real.

You are intentionally implying that taxonomic researchers are intentionally lying so they can get some lower impact papers out, the same papers that major universities won't give a crap about as far as tenure goes nor which will help there grant writing. You are effectively accusing the folks whose papers often drive this forum of fraud.

And taxonomic inflation certainly has been a term that has been argued, but I would say by a minority of individuals whose arguments usually come down to conservatism for conservatism sake, the idea itself.

 

[Mysticete]

Would you be able to separate unequivocally the different warblers by finding just 1-5 bones? (It does not really matter if you think about separating members of the American Wood Warblers or members of genus Phylloscopus). I doubt it would be possible but I do not know. But my expectation is that for reasons like this, the biodiversity in those ancient times are likely to be underestimated.
Niels

This is pretty much the reason why no one applies subspecies to fossil taxa, except in a few cases (mostly dealing with Holocene/Pleistocene taxa). Even with large sample sizes of still extant taxa, subspecies can be hard to define. Now imagine if your sample size is just a handful of humeri.

 

[Jon.Bryant]

And you're introducing politics over science?

Without trying to be rude to taxonomists - if there is a quasi scientific and non standard definition of a species, is it a true science?

Also, if we applied the ‘when in doubt rule, favour a species’ there would be no arguement of bias. It would be a bit like our legal system innocent till proven guilty.

With a more arbitrary evaluation system (and a choice of different taxonomic authorities saying different things) there seems to be more risk of gaming the system and playing politics.

 

[Jon.Bryant]

The problem is unsolvable - since evolution is a continuous process

This is kind of my conclusion. As we apparently don’t have a precise measure of a species, we cannot apply a ‘pass fail criteria’ to a continuous process - in contrast, say we had a definition of red, we could assess the continuous hues of white to pink to red and specify when the color was red (by our definition). Without a definition, we can only look at well differentiated taxa and apply a judgement.

With a definition we would run fowl of the problems that we have millions of individuals, so millions of continuous processes, that must interact and future winners and losers are not readily apparent.

 

[njlarsen]

There has been, as already stated, many definitions made. Even with a definition, there is still the problem of not everyone reading it exactly the same way.
Niels

 

[Jon.Bryant]

Fortunately (for us here) there's only 2 or 3 which are used by ornithologists, and BSC is leading the pack.

This is a slightly different issue - this relates to the principles as to what a species is, rather than the criteria under those principles.

 

[Jon.Bryant]

But we expect the working scientists to provide a yes-or-no answer

Actually I do not expect all the parties currently voicing an opinion, to make a judgement. I would argue that there are far too many taxonomic authorities trying to answer the same question, which the thread suggests is unanswerable or perhaps less harshly, just ‘a view’. It is nice that IOC and Clements ‘volunteered’ to answer the question, but I didn’t expect them to broadcast their opinion. BirdLife were tasked to access all species by IUCN, so it could be argued that they have a mandate and are ‘expected to’ answer the tricky question of what is a species.

Going back on an old thread, what I find surprising is that the authorities that volunteered an opinion seem in some cases to be so opinionated - we only have to look at the apparent slow progress of the WGAC (no webpage updates for a year now), to see that it is not a case of ‘well it was only my view, and I am more than willing to except yours’.

 

[njlarsen]

Going back on an old thread, what I find surprising is that the authorities that volunteered an opinion seem in some cases to be so opinionated - we only have to look at the apparent slow progress of the WGAC (no webpage updates for a year now), to see that it is not a case of ‘well it was only my view, and I am more than willing to except yours’.

Everyone have promised that the WGAC will not come out with updates until their version 1 is ready. However, both IOC and Clements have published plenty of changes they say come from that collaboration, so I don’t get your point?
Niels

 

[Mysticete]

Yeah, WGAC are continuing to make progress, they just don't necessarily share that progress on their webpage. Just look at the changes Clements and IOC have made. Almost all of the changes have been part of the reconciliation process. Wouldn't surprise me if at they are rate they are going the reconciliation process will be done in another year.

I don't think it's possible for any one checklist to have a mandate, because there is no overall authority to provide that mandate. I don't think that is a bad thing however; a diversity of opinions might be confusing for birders, but is good for science.

 

[Paul Clapham]

This is a slightly different issue - this relates to the principles as to what a species is, rather than the criteria under those principles.

Not at all. My point was that there were many sets of principles to characterize species.

 

[Paul Clapham]

This is kind of my conclusion. As we apparently don’t have a precise measure of a species, we cannot apply a ‘pass fail criteria’ to a continuous process - in contrast, say we had a definition of red, we could assess the continuous hues of white to pink to red and specify when the color was red (by our definition). Without a definition, we can only look at well differentiated taxa and apply a judgement.

Indeed. We don't even have a definition of colours (the Japanese divide green from blue differently than you and I do, the Russians and Italians have words for light blue and dark blue, paint stores have hundreds of colours) but that doesn't stop us from talking about red cars.

 

[Paul Clapham]

... which the thread suggests is unanswerable or perhaps less harshly, just ‘a view’....

That wouldn't be my opinion. It's not unlike the question "When does a child become an adult?" There's a continuum which obviously has "child" at one end and "adult" at the other end. People are perfectly ready to provide an answer to the question, as one can see. And yes, people have a variety of answers to the question which have been encoded into law all around the world. And if you've had children you will recognize the grey area where you are unsure whether to treat them as adults or not.

 

[Andy Adcock]

You could try reading Jerry Coyne and Allen Orr's book "Speciation". Executive summary: there's about 20 different ways that scientists classify species. Fortunately (for us here) there's only 2 or 3 which are used by ornithologists, and BSC is leading the pack.

Probably others in the thread have said something like this, but here's how I see it: at time X there's a group of birds which are freely interbreeding. A million years later, due to various external influences, there's two groups which breed freely within the groups but not between the groups. So speciation has occurred. But during that million years it's been confusing, both for us and for the birds. Hybrids may or may not have been produced, depending on what those external influences were.

But there's no instant during those million years when we can say "Then! That's when it happened!" There's only a long grey area when it happened. This implies that we are in that long grey area for many speciating groups. But we expect the working scientists to provide a yes-or-no answer when it's really not possible to do that, which results in the discussions which you can see in the literature.

(It's actually more complicated than that. But I think this is a reasonably good overview.)

The IOC's more holistic approach would suggest to me that they're more on the PSC track? The BSC maybe be 'leading the pack' with scientists but many, actual, field birders prefer the less rigid PSC.

Nobody has mentioned the 'Tobias scale' which awards points for certain criteria and like applying for a mortgage, you need so many points to be granted species status, at least I think that's how it works?

 

[Paul Clapham]

The IOC's more holistic approach would suggest to me that they're more on the PSC track? The BSC maybe be 'leading the pack with scientists but many, actual, field birders prefer the less rigid PSC.

Yeah, looks like it's possible to speak BSC with a PSC accent. It's grey zones all the way down.