Full and sub species (1 Viewer)

[helenol]

Can someone explain in laymans terms, the difference between a full species and sub species? Giving examples will also help!

Thanks.

 

[ashrich]

Hi Helen , well , try this ...Full species is the first or commonest described type , sub species can be regional variants with recognisable main features but maybe with slightly different feather configuration or vocal differences , subtle colour changes etc. those differences being fully described by someone of authority for it to be accepted . I'm sure though that may be clarified by another member who can explain better .

Ashley

 

[Barred Wobbler]

How about white wagtail/ pied wagtail?

 

[Nutcracker]

As a general rule, species don't interbreed with each other; subspecies can do.

But there's plenty of exceptions - e.g. Glaucous and Herring Gulls interbreed fairly freely in Iceland

 

[helenol]

How about white wagtail/ pied wagtail?

But which is which though?

 

[Dimitris]

Hey H.The above is correct.

But lem me give a try at it...:

As mentioned above by ashrich Full Species is the first to be described of the species it is also know as nominate race (or something like that).
Full species is a,how can I say it,a "true" species,ie it is significantly diffrent from its relatives and does not as a general rule breed with them.Even if it does the offspring should be sterile(this means that the species are difrent species and are not closely related) if the offspring are fertile this can mean 2 things:
a)the species are closely related(think Ducks)
or b)the species are the same species(Think the North American Junkos)

Now for the subspecies.They are also know as races.These races represent regional variants of the same species and differ only slightly from the nonminate species in voice,colour,shape even behaviour.Note that sub species can become full species.(Think of Chiff Chaffs).

In short all the subspecies of a true species are the same species (the same full species).They are simply variants.
However given time and the right conditions the subspecies can evolve into full species.
Note that telling what is what when trying to decide if something is a full or just a subspecies is very very complicated.
To complicate things even further.
The variation of a species can be clinal,which means that the species changes gradualy from one form to another.(Many Australian Species have this)
And secondly a species can have one or more phases.These are colour variants of the same species,apart from that they don't defer at all from the rest of theyr "normal" kin(think of Gyr Falcons) .

Hope this has been clear...And do correct me if I'm wrong...

Dimitris.

 

[Dimitris]

But which is which though?

It depends on which was described scientificly first(I do not know which was described first however.So I can't tell u).The devision is totaly human made.

 

[MikeDale]

The variations of the Yellow/Blue-headed Wagtail (Motacilla Flava group always astounded me. They look so different.

 

[Nutcracker]

Hi Dimitris,

Not very clear - but it isn't your fault , it can't be made clear as there is no simple division between the two, there is a full continuum of variation between things that are obviously distinct species (e.g. Osprey) right the way, gradually less and less distinct, through to birds which it is hard or debatable to even call them subspecies at all (e.g. your local Greek Blue Tits Parus caeruleus calamensis, some don't accept the validity of the subspecies at all)

So there are plenty (hundreds!) of cases where it is very debatable whether to call something a species or a subspecies - why are the ducks you cite different species, while the juncos aren't? It would be just as valid to split the juncos into several species and lump the ducks into one

Clines can be very tricky too, you have a species which varies a tiny little bit step by step across its range . . . but the extremes, if compared, are strikingly different, and if or when they ever meet up, don't interbreed and behave like species. A good one like this is Greenish Warbler: it has a cline that stretches from northeast Europe down through central Asia to the western Himalaya, along the Himalaya into China, back up through China and up into central Siberia. The two extremes have met up with each other somewhere in Siberia, and they behave as two different species (Greenish Warbler, Two-barred Greenish Warbler). But the cline all round the Himalaya shows they are the same species . . .

One good thing about it all - if it wasn't so complex, ornithology would be a lot less interesting!

 

[Dimitris]

Hi Dimitris,

Not very clear - but it isn't your fault , it can't be made clear as there is no simple division between the two, there is a full continuum of variation between things that are obviously distinct species (e.g. Osprey) right the way, gradually less and less distinct, through to birds which it is hard or debatable to even call them subspecies at all (e.g. your local Greek Blue Tits Parus caeruleus calamensis, some don't accept the validity of the subspecies at all)

So there are plenty (hundreds!) of cases where it is very debatable whether to call something a species or a subspecies - why are the ducks you cite different species, while the juncos aren't? It would be just as valid to split the juncos into several species and lump the ducks into one

Clines can be very tricky too, you have a species which varies a tiny little bit step by step across its range . . . but the extremes, if compared, are strikingly different, and if or when they ever meet up, don't interbreed and behave like species. A good one like this is Greenish Warbler: it has a cline that stretches from northeast Europe down through central Asia to the western Himalaya, along the Himalaya into China, back up through China and up into central Siberia. The two extremes have met up with each other somewhere in Siberia, and they behave as two different species (Greenish Warbler, Two-barred Greenish Warbler). But the cline all round the Himalaya shows they are the same species . . .

One good thing about it all - if it wasn't so complex, ornithology would be a lot less interesting!

couldn't agree more!

 

[Rasmus Boegh]

To give a somewhat more up-to-date (yet still highly simplified) view on species versus subspecies than what has been presented earlier - this is what most (but not all) biologists believe today, which is basically the Biological Species Concept described in previous posts, though modified with (among others) featured from the Recognition Species Concept:

Two populations are different species if they under "normal" circumstances either are completely unable to interbreed or only able to interbreed with reduced success. Do note that "able" to a large degree also includes "willing" (this is the part taken from the Recognition Species Concept): If two closely related populations are completely unable ("unwilling") to interbreed because of a difference in e.g. voice, they are effeciently isolated in terms of reproduction even though they might be able to interbreed successfully if forced via artificial measures. By "reduced success" in terms of interbreeding is ment that the hybrid offspring is in a rather poor position, i.e. it is either completely sterile, has a relatively lower fertility or a relatively higher rate of mortality. This is where the Junco versus the Duck problematic generally differ as hybrid Juncos appear to live a relatively "normal" life for a Junco, while hybrid ducks generally have a lower level of fertility and/or a higher mortality-rate than the "pure" forms. As such the genetic and morphologic integrety of the species doesn't break down.

Subspecies: If a species has two or more populations that will successfully produce offspring if meeting, but still are recognizable from each other via morphology or physiology (note that subspecies are not described on basis of voice, behavior or biochemistry - though this may change in the future). The term "nominate" is indeed (as mentioned by Dimitris) used for the first subspecies described for a species, though it is not used in monotypic species (= species without recognizable subspecies). While used far less frequently, "nominate" is also used at species level taxonomy (i.e. first species described for a genus).

Relatively recently, another species concept has started gaining a level of recognition (though it is still only a minority of biologists who follow it). This is the so-called Phylogenetic Species Concept. Without going too much into detail, it basically means that all subspecies would be recognized as species (and therefore subspecies would cease to exist). A significant problem is that most species are described via the modified Biological Species Concept, while some recent splits (some North Hemisphere Gulls, etc.) largely are based on the Phylogenetic Species Concept and as such there is a serious problem with the lack of consistency.

Anyway, above is a highly simplified version, as it in reality is far more complicated with things like various intermediates between species and subspecies, ringspecies (as described by Peter), megasubspecies, allospecies, reductive speciation, clines (as mentioned in previous posts), additional species concepts and far, far more...

 

[citrinella]

Can someone explain in laymans terms, the difference between a full species and sub species? Giving examples will also help!

Thanks.

Perhaps it is worth remembering that "species" is a term invented by man. Nature has no reason to conform to any particular definition of the term.

Mike.

 

[Jane Turner]

But which is which though?

In the is case Helen it would be technically correct to describe Pied Wagtail Montacilla alba yarelli as a race of White Wagtail M.a. alba.

Of course the logic breaks down immediately at Yellow Wagtail... Montacilla flava where in the UK at least it is normal to describe the species as Yellow Wagtail, the UK race M.f.flavissima as Yellow Wagtail, and the nominate race M.f.flava is called Blue-headed Wagtail

 

[Rasmus Boegh]

Note that exact taxonomy and English names often not are directly related. English names (or for that matter German, Danish, etc.) are usually based on local customs, while species and subspecies names are given after a strict code (called the Linnaeus System) - and as such there is little meaning in comparing English versus Scientific names directly against each other. To give a brief intro to a part of the Linnaeus System via the example mentioned by Jane, the Yellow Wagtail:

Species (first part being genus - in plural "genera" - and second part being the specific species name):

Montacilla flava (with Montacilla being genus, flava being the specific species name).

There are several subspecies of this species;

Nominate subspecies aka nominal form (i.e. the first to be formally described):

Montacilla flava flava (usually shortened Montacilla f. flava).

other subspecies (note that they are referred to as subspecies of the species and not subspecies of the nominal form):

M. flava flavissima
M. flava iberiae

(and of course all the other subspecies).

The problem with above system is that it is rather rigid. The second we accept evolution - that one species can evolve from being species a to being species b - we must accept that there is something in between - a place where it is too evolved to be species a, but not evolved enough to be species b. No-one has yet been able to present a system that gives a good solution to this problem.

 

[Tannin]

Rasmus is right on the money. I'll try to translate his account into simpler terms.

First, forget all about questions of "how different" Bird A and Bird B are. That has nothing to do with species/subspecies distinctions. Any consistent difference is sufficient to differentiate between different populations - it doesn't matter how large or small the difference is, just so long as there is a consistent and recognisable difference.

Both species and subspecies have differences (call, plumage, length of tail - it doesn't matter what this difference is).

Both species and subspecies do not, as a general rule, interbreed. This is not a fixed, absolute rule - the key point is that there is no significant gene flow between two populations. This applies equally. (What counts as "significant" gene flow, of course, is a matter for judgement. Expert opinions will sometimes differ.

You are justified in making a subspecies distinction when, although there is little or no gene flow between the two populations, you have reason to believe that there would be gene flow if it were practicable - typically, the two subspecies are geographically isolated, but if you were to bring them together in the same place then they would interbreed.

You are justified in making a species distinction when there is little or no gene flow and you have reason to believe that there would still be little or no gene flow even if the two populations were brought together in the same place.

Notice that difference alone is not enough to justify either categorisation: for example, some humans have blue eyes, some brown. Although it's an obvious difference, there is clearly gene flow (i.e., interbreeding) between blue-eyed and brown-eyed humans and neither one is a seperate species or subspecies.

Nor, taken alone, is lack of gene flow enough to justify a distinction - often, this is simply because there are two populations that don't happen to meet regularly enough for gene flow to take place.

You only get a species/subspecies dstinction when you have both difference and lack of gene flow. If that lack of gene flow is because they can't/won't interbreed, then you have two different species. If it's because they can interbreed readily but are prevented from doing so by some circumstance (such as living in different geographical areas), then you have two different subspecies.

Finally, we should consider the case where you have a mere clinal variation. For example, Koalas in southern Australia and those in northern Australia are obviously quite different. You can tell them apart at a glance. But as you travel between the ends of the continent you see that those in-between are in fact ... er .. in-between! A NSW Koala looks like a cross between a Qld Koala and a Victorian Koala - and in fact, that's exactly what it is! They interbreed freely from one district to another and, over time, genes travel back and forwards via many matings and many generations all the way up and down the continent. Thus, because there is significant gene flow, the different Koala populations are regarded as simply a single species with variant types: there are no Koala subspecies. A great many birds do the same sort of thing, of course.

 

[cuckooroller]

In the is case Helen it would be technically correct to describe Pied Wagtail Montacilla alba yarelli as a race of White Wagtail M.a. alba.

It all gets a bit confusing when one gets away from the nomenclature and taxonomy afforded using rigorously only one list. In this case, the term Pied Wagtail is a vernacularly used term expressing only race yarelli. To be punctilious but less confusing, both race yarelli and nominate race alba are White Wagtail. Any scientific binomial - Motacilla alba - is a White Wagtail, so Motacilla alba (+ any of about 10 subspecies) are all White Wagtails.

It would be incorrect to say that Motacilla alba yarelli is a race of Motacilla alba alba, but correct to say that it is a race of Motacilla alba.

 

[helenol]

Phew, I think I need a lie down! Thanks very much for all your input.

Still a little confused, but Tannins explanation of the difference and lack of gene flow makes it a little easier to understand.

Thanks again.
Regards

 

[James Blake]

Rasmus is right on the money. I'll try to translate his account into simpler terms.

First, forget all about questions of "how different" Bird A and Bird B are. That has nothing to do with species/subspecies distinctions. Any consistent difference is sufficient to differentiate between different populations - it doesn't matter how large or small the difference is, just so long as there is a consistent and recognisable difference.

Both species and subspecies have differences (call, plumage, length of tail - it doesn't matter what this difference is).

Both species and subspecies do not, as a general rule, interbreed. This is not a fixed, absolute rule - the key point is that there is no significant gene flow between two populations. This applies equally. (What counts as "significant" gene flow, of course, is a matter for judgement. Expert opinions will sometimes differ.

You are justified in making a subspecies distinction when, although there is little or no gene flow between the two populations, you have reason to believe that there would be gene flow if it were practicable - typically, the two subspecies are geographically isolated, but if you were to bring them together in the same place then they would interbreed.

You are justified in making a species distinction when there is little or no gene flow and you have reason to believe that there would still be little or no gene flow even if the two populations were brought together in the same place.

Notice that difference alone is not enough to justify either categorisation: for example, some humans have blue eyes, some brown. Although it's an obvious difference, there is clearly gene flow (i.e., interbreeding) between blue-eyed and brown-eyed humans and neither one is a seperate species or subspecies.

Nor, taken alone, is lack of gene flow enough to justify a distinction - often, this is simply because there are two populations that don't happen to meet regularly enough for gene flow to take place.

You only get a species/subspecies dstinction when you have both difference and lack of gene flow. If that lack of gene flow is because they can't/won't interbreed, then you have two different species. If it's because they can interbreed readily but are prevented from doing so by some circumstance (such as living in different geographical areas), then you have two different subspecies.

Finally, we should consider the case where you have a mere clinal variation. For example, Koalas in southern Australia and those in northern Australia are obviously quite different. You can tell them apart at a glance. But as you travel between the ends of the continent you see that those in-between are in fact ... er .. in-between! A NSW Koala looks like a cross between a Qld Koala and a Victorian Koala - and in fact, that's exactly what it is! They interbreed freely from one district to another and, over time, genes travel back and forwards via many matings and many generations all the way up and down the continent. Thus, because there is significant gene flow, the different Koala populations are regarded as simply a single species with variant types: there are no Koala subspecies. A great many birds do the same sort of thing, of course.

Hi Tannin

Thanks for your very clear explanation of various concepts.

Are there any competing subspecies concepts? The one you mention seems to have certain flaws (like, probably, all species concepts). For instance, it seems to imply that two previously isolated populations lose their subspecies status as soon as they meet up and interbreed, which seems far too cut-and-dried.

And how would it apply to humans? Before the current era at least some populations were relatively isolated.

Any comments appreciated.

James

 

[Rasmus Boegh]

Are there any competing subspecies concepts?

No, there are not any competing "subspecies concepts", at least not to a significant level. However, there are concepts (as mentioned in one of my previous posts) where subspecies don't exist, but are elevated to species. Also note that while they are refered to as "species concepts", they generally deal with all levels.

The one you mention seems to have certain flaws (like, probably, all species concepts). For instance, it seems to imply that two previously isolated populations lose their subspecies status as soon as they meet up and interbreed, which seems far too cut-and-dried.

To some extent, it actually fits well with what can be seen in the nature. If two populations that are only worthy of subspecific recognition meet, they will usually interbreed freely (except extremes in ring species). If two such populations are afforded a consistent and extensive exposure (gene flow) to one another, they will start acting as clines of a single population and often (but not always, some remain clines) end up as a single population where the variation purely is at an individual level. However, you are also right in the fact that there is a serious problem with all these theories. Part of the problem is due to the theories having been greatly simplified here to make them "digestable" to most. A more significant problematic was the one I tried to explain earlier, though using species as a reference - if we accept evolution we also have to accept intermediate populations (see the last part in post #14). Biologists, scientists and alike are well aware of this significant problem in these theories - we just don't have anything better at this point! The modified Biological Species Concept also do relatively poorly in terms of Botany and Paleontology.

And how would it apply to humans? Before the current era at least some populations were relatively isolated.

Yes, there are no doubts that until relatively recently recognizable populations of humans lived isolated from one another (though the vast majority acted as clines). However, this is a very problematic discussion. The problem is that such recognition usually has been bogus science intended specifically as an argumentation for racism. Due to history (Nazism and alike) very few biologists would dare having a serious look at any extant human in this context...

 

[James Blake]

Thanks for all that, Rasmus.

Yes, I find it depressing how any scientific discussion of human difference gets either
(i) hijacked by racists
or
(ii) stifled by fear of racism even when none is intended.

As I understand it Homo sapiens is interesting for having a lot of physical variation while being very homogenous genetically. Going by surface features such as complexion, I guess we have a whole series of clines, eg from northern Europe to north Africa.

regards
James