Domestic Fowl Taxonomy

[Cassidy Casuar]

I am aware of the fact that this is not particularly zoo-related and might not belong here, but it would be good if someone could answer this.
To my understanding, Domestic Fowl are classified as a subspecies of the Red Junglefowl. If this is true, then does this mean that the evidence of them being the descendants of Red x Green and/or Red x Grey Junglefowl is being ignored? Why are they not instead classified as a hybrid "species"?
Thanks in advance for any help.

 

[Chlidonias]

basically, domestic animals are a bit vague taxonomically and there isn't a lot of consistency in how they are treated. They generally waver between being considered the same as their wild ancestors, being considered subspecies, and (especially recently) being completely split off as full species. It depends on author and the trend of the time, and of course each species needs to be considered on its own merits not under an overall "domestic animal" banner. You'd be lucky to find any domestic animal where there is a firm consensus on how to name it. The best you can usually manage is something like "at the current time, most authorities consider x to be called by this scientific name". It is further complicated by situations where even the ancestor species is disputed, and of course by situations where there may be several ancestor species mixed together (as in some of the domestic bovids).

For domestic chickens the base stock is red junglefowl Gallus gallus. Any additional genetics from other junglefowl species are small, so they are still considered to be domesticated red junglefowl. I can't see there being any case for splitting them into a separate species.

 

[Cassidy Casuar]

You'd be lucky to find any domestic animal where there is a firm consensus on how to name it.

What about domestic rabbits? I have never seen them being classified differently from wild European rabbits, which are undoubtedly their only wild ancestors.

 

[Chlidonias]

well there's one then Also mice, and rats too I guess. I was thinking more along the lines of farm and working animals, so overlooked the pet ones.

 

[billnaylor]

Subspecies is an exclusive term for a population of a species that differs physically.
A domestic variety can't be subspecies, as it is not part of the wild population.
Sub species or race is merely a convenient term for identifying different populations within a species.
Once a wild species is selectively bred the variations are termed varieties.
Although interestingly if some of those varieties produced by artificial selection in captivity such as in domestic dogs,poultry and pigeons were found in the wild, they would be classified as distinct species.But being domestic they are termed varieties of one or more wild specie.
Many zoo animals bred over a number of generations sometimes incorporating genes from different subspecies may no longer resemble the true wild type species.
And even if they do, their genes may not be pure.

 

[Chlidonias]

Subspecies is an exclusive term for a population of a species that differs physically.

Partly true. The subspecies does not have to differ physically. There are many instances where subspecies are or have been named based solely on geographical separation and cannot be distinguished otherwise.

A domestic variety can't be subspecies, as it is not part of the wild population.

They can and they commonly are.

Sub species or race is merely a convenient term for identifying different populations within a species.

Exactly. "Subspecies" is a subjective human construct, and hence your preceding statement becomes meaningless

Once a wild species is selectively bred the variations are termed varieties.

The different forms within the domesticated animal may be called varieties (or breeds) but the overall animal (say the domestic chicken) is not called a variety.

Although interestingly if some of those varieties produced by artificial selection in captivity such as in domestic dogs,poultry and pigeons were found in the wild, they would be classified as distinct species.But being domestic they are termed varieties of one or more wild specie.

Not true at all. A domestic muscovy or domestic pigeon in the wild would quite plainly be considered the same species as its wild ancestor, it is just a domesticated form. A Siamese cat may not look at all like a wild cat but it is easily shown to not be a distinct species in its own right. In some animals the domestic can be shown to be now genetically distinct from the wild ancestor (say, Bactrian camels) but otherwise your statement is completely wrong.

Many zoo animals bred over a number of generations sometimes incorporating genes from different subspecies may no longer resemble the true wild type species.
And even if they do, their genes may not be pure.

I'm not sure what this has to do with chickens but it is a fairly obvious thing to say. Many zoo animals are subspecific hybrids and many are horribly inbred.

 

[lamna]

Taxonomy is a real mess, mostly because animals won't follow the rules. Some species separate for millions of years breed and produce fertile a fertile hybrid species, others look very similar but have been genetically distinct for hundreds of thousands of years.

Hopefully in 20 years things will be sorted out, but for now don't take taxonomy too seriously, the rules are still being rewritten.

 

[Jackwow]

I thought this thread was meant to be about stuffing chickens?!

 

[billnaylor]

Reply to Childonias from Bill Naylor

The term Domestic fowl taxonomy is a misnomer.
As zoological taxonomy is not applied to domestic animals.

Your quote:
The subspecies does not have to differ physically.
There are many instances where subspecies have been named based on geographical separation.

Not true. The classic definition of subspecies repeated through many zoology textbooks is ‘a subspecies is population that can be morphologically distinguished’ (Morphological, shape and form) Hence the time spent by zoologists measuring and weighing wild caught animals.
When a population is distinct from other members of the species it can be considered a subspecies or race. If there were no variation why would it be termed a race?

Your quote: A domestic variety can be a subspecies and they commonly are.

No they are not. Total misconception of the term subspecies.

Your quote: subspecies is a subjective human construct.
Man made you mean?
Well so are species, genus and all other taxonomic ranks.
Which I need to emphasise are used as biological classification for exclusively wild species, not domestic varieties of species.
But the point I was making was that subspecies is a convenient way of categorising a variant population within a species, produced by natural selection. It isn’t applied to domestic varieties produced by artificial selection.
My statement: If some of those varieties produced by artificial selection in captivity such as domestic dogs poultry and pigeons were found in the wild, they would be classified as distinct species. I was referring to domestic varieties which have become changed dramatically from the wild ancestor through selective breeding, such as in the Chihuahua. Or Aylesbury duck, totally unlike it’s wild ancestor the European Mallard.
I’m not the first to make this point. Darwin wrote about the diversity of domestic pigeons breeds, all originating from their common ancestor the Rock dove.which he observed, if occurring in the wild would be distinct species
Your reply that a domestic pigeon or domestic muscovy in the wild would be considered the same species, is stating the obvious, and missing the point that Darwin and I were speaking hypothetically, to make the point that
the diversity of domestic breeds has parallels with the evolution of
wild species.
I apologise if my point about zoo animals incorporating genes from different subspecies was obvious. I was just trying to emphasise that a wild species bred in captivity like domestic species, is no longer shaped by natural selection.
And even with the best intentions the captive environment will impact on it
physically and mentally. And over time it will become a wild type domestic animal.
My quote: Once a wild species is selectively bred the variations are called varieties.
Your reply:
The over all animal (say the domestic chicken) is not a variety.

The domestic chicken is obviously a variety as it is does not in anyway resemble its ancestor the Red Jungle fowl. If a domestic animal resembles its wild ancestor it’s termed wild type.

 

[Chlidonias]

I haven't got time really to constuct a detailed reply to billnaylor because you have many misconceptions and personal opinions in there, as well as outdated notions (e.g. the one referencing how species were considered at the time of Darwin - you know, before anyone even knew what a gene was!), not to mention the misquoting of what I wrote. Suffice to say, I leave my original reply to you as it stands.

 

[billnaylor]

Which out dated notions? The discovery of how genes worked by Mendel and subsequent discovery of DNA by Crick and Watson supports and confirms Darwin’s theory of evolution and common ancestry by means of natural selection. A theory that included data from captive breeding. some of which Darwin acquired personally from his own experiments mainly with varieties of pigeons and fowls.
(Note variety, not subspecies) Like all plant and animal breeders in the 1800’s Darwin was aware of inherited (dominant ) and passive (recessive traits), but was unaware
genes were responsible.
Members will be able to draw their own conclusion from the postings as to whether you were misquoted.

 

[DDcorvus]

The term Domestic fowl taxonomy is a misnomer.
As zoological taxonomy is not applied to domestic animals.

Your quote:
The subspecies does not have to differ physically.
There are many instances where subspecies have been named based on geographical separation.

Not true. The classic definition of subspecies repeated through many zoology textbooks is ‘a subspecies is population that can be morphologically distinguished’ (Morphological, shape and form) Hence the time spent by zoologists measuring and weighing wild caught animals.
When a population is distinct from other members of the species it can be considered a subspecies or race. If there were no variation why would it be termed a race?

We moved quite bit beyond that, there is are discussion going on what to do with species that look the same but are genetically very distinct the main debate varies between classifying these as different subspecies or different species, but there is quite a lot of agreement that genetic difference should be recognized.

Your quote: A domestic variety can be a subspecies and they commonly are.

No they are not. Total misconception of the term subspecies.

Actually they are, not individual races but the domestic form of a species is in most cases classified as a separate subspecies see canis lupus familiaris, bos taurus taurus, felis silvestris catus. Only case of very recent domesticated species this is not the case like in Melopsittacus undulatus. You might disagree with this but then I propose you start working on a peer-reviewd article on the taxonomy of domesticated varieties.

I apologise if my point about zoo animals incorporating genes from different subspecies was obvious. I was just trying to emphasise that a wild species bred in captivity like domestic species, is no longer shaped by natural selection.
And even with the best intentions the captive environment will impact on it
physically and mentally. And over time it will become a wild type domestic animal.

Actually populations in captivity are influenced by things like genetic drift, but as well by natural selection (please note that natural does not have to mean to be shaped by being in the wild) only the selection pressures are very different from the populations in the wild. How do individuals cope with human pressence or being fed different food etc etc. We do agree on the end result that this makes that over time captive populations start to differ quite a lot from the wild populations. In some bird species there are indications this can happen already in a couple of generations. A solution would be to ensure that there is an exchange between the captive and wild populations to limit these effects although this will make management more challenging.

 

[Pertinax]

The domestic chicken is obviously a variety as it is does not in anyway resemble its ancestor the Red Jungle fowl. If a domestic animal resembles its wild ancestor it’s termed wild type.

Some domestic fowl do resemble Red Jungle fowl. The ancestral 'black/red'/ wild-type colouration is found as either predominant in e.g the Welsummer, or as one of several colours (varieties) in a number of breeds, -the cockerels that is, while the hens follow the 'partridge' colouration of the female ancestor.

I would reserve the term 'variety' for the offshoots- in type, colour, appearance etc- of an already domesticated species, for which I think the most accurate term may be 'breed'- as in 'domesticated breed'.

 

[billnaylor]

We moved quite bit beyond that, there is are discussion going on what to do with species that look the same but are genetically very distinct the main debate varies between classifying these as different subspecies or different species, but there is quite a lot of agreement that genetic difference should be recognized. END

BN.
Regarding species that are identical, yet genetically different you are of course referring to invertebrate species. With respect, on this forum we are discussing vertebrates. But as there are many more invertebrates than vertebrates, I concede my statement was only valid for vertebrates.

QUOTE:
Actually they are, not individual races but the domestic form of a species is in most cases classified as a separate subspecies see canis lupus familiaris, bos taurus taurus, felis silvestris catus. Only case of very recent domesticated species this is not the case like in Melopsittacus undulatus. You might disagree with this but then I propose you start working on a peer-reviewd article on the taxonomy of domesticated varieties. END

BN:
Thanks for the proposal. Regarding sub specific names:
There is inherent inconsistency when so-called sub specific names are assigned to domestic animals. I say so-called, because usually a third name is added simply to distinguish the domestic form. Often appearing to be chosen at random.
When DNA analysis is used to identify a common ancestor it can create more inconsistency. (Canis-lupus-familiaris) is used to describe the domestic dog
by equally as many authors as use (Canis-familiaris). Both names are also accepted as valid by ITIS who oversee taxonomic names. Which gives the impression scientific names for domestic animals are of little consequence. Which is in many ways true.
The name of the breed (variety) is the only real requirement
Scientific names are used as an animal’s universal specific identification.
How does a (Canis-lupus-familiaris) distinguish an St Bernard from a poodle?
(Bos-taurus-taurus), which you name as an example of a domestic subspecies, is
other than cow, more frequently referred to as (Bos-taurus.)
The domestic cat was classified by Linneaus as (Felis-catus)
and as you point out, is now known as (Felis-silvestris-catus). But it’s also known as
( Felis-domestica.) With its common ancestor being of the wild cat genus Silvestris some people refer to it as (Felis-silvestris-domestica) why not simply use Carl’s name (Felis-silvestris)?
The International Council on Nomenclature’s ruling has always been the wild ancestor’s scientific name should also be the domestic name. But authors have the habit of distinguishing the domestic form with a third name for convenience.
which in no way validates it as a true subspecies. Which by definition is a race A distinct geographical population.
You say that in the case of recently domesticate species such as the budgerigar
subspecific names are not used. In the case of the budgerigar its name is probably long enough.) But your not strictly correct. Domestica has been frequently been used for the canary. But inconsistency regularly rears its head. The red factor canary is the result of hybridisation with the South American Red Siskin (Spinus-cucullata) it has different genes than any other canary, if assigning subspecific names to domestic species was a level playing field, it would warrant a subspecific name.
Yet like all domestic canary breeds have the scientific name of the Atlantic canary (Serinus- canaria).
You can’t get anymore less recent than the domestic pigeon, the oldest domesticated bird species. Yet its scientific name, like its ancestor the rock dove is (Columba- livia). There are a myriad of varieties of domesticated (Columba-livia) So why no subspecific name?


QUOTE:
Actually populations in captivity are influenced by things like genetic drift, but as well by natural selection (please note that natural does not have to mean to be shaped by being in the wild) only the selection pressures are very different from the populations in the wild. How do individuals cope with human pressence or being fed different food etc etc. We do agree on the end result that this makes that over time captive populations start to differ quite a lot from the wild populations. In some bird species there are indications this can happen already in a couple of generations. A solution would be to ensure that there is an exchange between the captive and wild populations to limit these effects although this will make management more challenging.

BN:
Sorry but captive animals are not subject to natural selection no matter how much you stretch the definition. They are totally isolated from their ecosystem which includes weather, flora and fauna which they interact with. And it’s one of the main challenges zoos have to meet, to simulate and compensate. And they’ll always fall short.

 

[billnaylor]

Domestic chicken and red jungle fowl indistinguishable

Some domestic fowl do resemble Red Jungle fowl. The ancestral 'black/red'/ wild-type colouration is found as either predominant in e.g the Welsummer, or as one of several colours (varieties) in a number of breeds, -the cockerels that is, while the hens follow the 'partridge' colouration of the female ancestor.

I would reserve the term 'variety' for the offshoots- in type, colour, appearance etc- of an already domesticated species, for which I think the most accurate term may be 'breed'- as in 'domesticated breed'.

Okay, there is some similar plumage, but c'mon a domestic chicken alongside any species of Jungle fowl would be picked out of a line up.
Lifes complicated enough as they say on the adds, variety is synonymous with breed, why change it?

 

[Chlidonias]

Which out dated notions? The discovery of how genes worked by Mendel and subsequent discovery of DNA by Crick and Watson supports and confirms Darwin’s theory of evolution and common ancestry by means of natural selection. A theory that included data from captive breeding. some of which Darwin acquired personally from his own experiments mainly with varieties of pigeons and fowls.
(Note variety, not subspecies) Like all plant and animal breeders in the 1800’s Darwin was aware of inherited (dominant ) and passive (recessive traits), but was unaware
genes were responsible.

nobody said the discovery of DNA disproved evolution. What you said was that varieties of domestic animals would be considered distinct species if found in the wild, and used Darwin's opinion as such as evidence. It means nothing because at the time of Darwin, species limits were generally determined by outward appearance because they didn't have the benefit of genetic analyses. That Darwin may have thought that a, say, pekingese would be considered a different species to a wolf is completely irrelevant today.

With regards to "experiments mainly with varieties of pigeons and fowls. (Note variety, not subspecies)" -- yes, varieties. Nobody has disputed that domestic animals are composed of many individual varieties. But the whole animal itself is not a variety (as Pertinax earlier noted but you do not seem to agree with).

Members will be able to draw their own conclusion from the postings as to whether you were misquoted.

yes, they will. By reading what you wrote


I'll leave your replies to DDCorvus for him to reply to your misinterpretations and mistakes.

 

[Pertinax]

Okay, there is some similar plumage, but c'mon a domestic chicken alongside any species of Jungle fowl would be picked out of a line up.
Lifes complicated enough as they say on the adds, variety is synonymous with breed, why change it?

1. The 'black/red' plumage is the same as the wild bird from which it derives. I said that birds with this plumage colour resembled Jungle Fowl- I did not say they were indistinguishable as per your subheading above- the two things are quite different. Obviously most domestic chickens do differ in shape, size etc from Jungle Fowl, as well as having many other colour forms.

2. Variety is not quite synonymous with breed. A 'breed' can sometimes have many 'varieties'.

 

[DDcorvus]

I'll leave your replies to DDCorvus for him to reply to your misinterpretations and mistakes.

Here I go then

Regarding species that are identical, yet genetically different you are of course referring to invertebrate species. With respect, on this forum we are discussing vertebrates. But as there are many more invertebrates than vertebrates, I concede my statement was only valid for vertebrates.

I was actually referring to vertebrate species as well. You might wanna have a closer look into Crocodylus suchus. Als research from 2011 showed that in Argentina there are 3 genetically different populations of Burrowing parrots out which 2 of them look exactly similar but there has been no exchange of genes later then 9.000 years ago. And you also might be aware of the genetic distinctiveness of the Bryde's whale population in the golf of Mexico.

There is inherent inconsistency when so-called sub specific names are assigned to domestic animals

There is inherent inconsistency in the naming of non-domestic species as well. Put 3 Taxonomists in a room and you will get 5 different proposals. This makes the discussion around classifying domestic animals as subspecies very similar to the debates around species with wild population.

Sorry but captive animals are not subject to natural selection no matter how much you stretch the definition. They are totally isolated from their ecosystem which includes weather, flora and fauna which they interact with. And it’s one of the main challenges zoos have to meet, to simulate and compensate. And they’ll always fall short.

Firstly animals in captivity are under selection, there are always individuals that seem to fit more than others and leave us with more offspring. You can call it natural or not but in the end it is the same process is the animal suitable for the habitat it is living in. Only in the case the habitat is a man-created one in captivity. And it is one that always will differ from the natural one.

 

[billnaylor]

Another distorted reply,

nobody said the discovery of DNA disproved evolution.
What you said was that varieties of domestic animals would be considered distinct species if found in the wild, and used Darwin's opinion as such as evidence. It means nothing because at the time of Darwin, species limits were generally determined by outward appearance because they didn't have the benefit of genetic analyses. That Darwin may have thought that a, say, pekingese would be considered a different species to a wolf is completely irrelevant today.

With regards to "experiments mainly with varieties of pigeons and fowls. (Note variety, not subspecies)" -- yes, varieties. Nobody has disputed that domestic animals are composed of many individual varieties. But the whole animal itself is not a variety (as Pertinax earlier noted but you do not seem to agree with).


yes, they will. By reading what you wrote


I'll leave your replies to DDCorvus for him to reply to your misinterpretations and mistakes.

No bias there then. You have already decided my replies will be full of mistakes and misinterpretations.
I must say you have an amusing knack for confidently grasping the wrong end of the stick. Then issuing an illogical comment such as:
"The whole animal is not a variety." What does that mean? The entire domestic population? If a domestic animal doesn't resemble
the wild type, yes it is a variety. DDCorvus, your spokesperson, well chosen. The same guy who believes captive animals are subject to natural selection.It's been entertaining but life's too short to continue.

 

[DDcorvus]

No bias there then. You have already decided my replies will be full of mistakes and misinterpretations.
I must say you have an amusing knack for confidently grasping the wrong end of the stick. Then issuing an illogical comment such as:
"The whole animal is not a variety." What does that mean? The entire domestic population? If a domestic animal doesn't resemble
the wild type, yes it is a variety. DDCorvus, your spokesperson, well chosen. The same guy who believes captive animals are subject to natural selection.It's been entertaining but life's too short to continue.

A shame Bill that you stopped responding on content and in case of of my believe I would recommend Frankham's 2008 paper: Genetic adaptation to captivity in species conservation programs

If you feel that is not enough I also have another paper that deals more with a particular group of animals.