I was wondering if a species created due to captive selection a valid species?
Well that really depends on your definition of “valid species” (for which there are already lots of discussions, such as this). I’m not sure I can think of any “true species” that have been bred artificially, although there are lots of “subspecies”, “varieties”, hybrids, etc. I’m sure some do exist though (if only because enough people say they do); do you have any particular organism in mind?. And then there’s genetically edited (created?) species, which are a whole separate question…
I guess Canis familiaris is an interesting debatable example. Some authorities consider it a distinct species, and others consider it a subspecies of wolf (Canis lupus familiaris).
Some crop plants have had their ploidy level changed, which can in some cases make them unable to breed with their previous strain… I’m not really sure but I think if wild plants spontaneously change their ploidy level that might qualify them as a new species?
Corn (Zea mays) is a clearer example. It’s a hybrid between at least three wild species, and has been bred to the point that it doesn’t really resemble its ancestors at all.
Not to mention it is unlikely to survive without humans. Corn really doesn’t have a method for seed dispersal.
Here are two interesting articles showing how species change very quickly when raised in captivity.
I should add that I have also read that researchers believe that habitat and food plant loss is the biggest threat to monarch butterflies.
A researcher in Switzerland has created ex novo a species (according to Mayr’s definition) of Drosophila.
In South America we got the Guanaco (Lama guanicoe), the wild ancestor, and the llama (Lama glama), the domesticated one.
The vicuña is the wild ancestor of the alpaca; and they’re regarded as different species.
Vicuña and Guanaco live in the wild. Llamas and alpacas are found only domesticated
The Quagga Project is trying to crossbreed our zebras back to the extinct species. Maybe.
If you cross breed a species in captivity could it be set free and considered wild?
Hybrid speciation is a valid way many plant species are created, both in wild and often by humans.
There’s certainly debate about the taxonomy of domesticated species versus their wild ancestors, such as the domesticated horse (Equus ferus caballus or Equus caballus ?), which in its feral state is often erroneously called a wild horse. Some biologists propose assigning the domesticated form as a subspecies of the wild form, but to me this raises all sorts of issues. Since domesticated animals are often derived from multiple wild sources, a domesticated subspecies doesn’t really fit with the typical definition of what a subspecies in the wild is. Then again, the domesticated form is often not genetically isolated from the wild form suggesting they are conspecific (although genetic isolation is not really a prerequisite for recognition of a species these days). Perhaps the best argument for recognizing the domesticated form as a separate species from the wild (ancestral) form is to avoid confusion as to what animal we’re talking about.
Added: I tend to follow the rationale in this paper: Gentry, A., J. Clutton-Brock, and C. P. Groves. 2004. The naming of wild animal species and their domestic derivatives. Journal of Archaeological Science 31:645-651.
There’s certainly debate about the taxonomy of domesticated species versus their wild ancestors
Conversely what of wild species that interbreed readily and often with domesticated counterparts - are they still their own species or something new entirely?
For example, many wild boar, mallard duck, and wildcat populations (and even certain wolf populations with domestic dogs) have long histories with interbreeding with local domestic pigs, domestic ducks, and domestic cats respectively. We can measure these rates of introgression by looking at their genomes. Are then these populations no longer valid populations belonging to that species (“wild boar” or “mallard” or “wildcat” proper)? Especially if these animals have an external appearance that conforms to what we would think of as a legitimate wild boar, or wild mallard, or wildcat?
This is why I think splitting domestic populations from their wild ancestors/conspecifics as separate species is silly. I get why some do it, especially for conservation purposes in the case of wildcats, but from a purely biological/cladistics point of view it makes no sense.
It goes to show that what we decide is defined as a species is often quite arbitrary and subject to the agendas of the parties involved.
Not sure if this is an example or not, but Cattle(Bos taurus and Bos indicus) are both classified as their own species and not as subspecies or forms of the now extinct Aurochs(Bos primigenius) despite being completely derived from them.
Domestic ducks are nothing but Mallards though, they’re not a new species. Pigs too become very boar-like when put in the wild. But dogs have started with own population, it’s gone and it was different, so they’re ssp. or different species based on those ancient dogs too other than only being domesticated.
Domestic dogs are a bit of an odd creature for sure.
They’re certainly the grey wolf’s closest relative, to the point that many studies classify them as the same species, just as different subspecies. In fact, domestic dogs and Holarctic grey wolves are more closely related to each other than either are to Indian and Himalayan wolves.
“The data suggest that an ancient, now extinct, central European population of wolves was directly ancestral to domestic dogs.” - https://science.sciencemag.org/content/342/6160/871
“The domestic dog (Canis lupus familiaris or Canis familiaris) is a subspecies of the gray wolf (Canis lupus).” - https://www.uniprot.org/proteomes/UP000002254
This reference for the dog’s genome data refers to it as C. lupus familiaris, aka a subspecies of the wolf - https://www.ncbi.nlm.nih.gov/projects/mapview/static/dogsearch.html
Pertaining to my original question above, should these ‘wolf’ populations be counted as valid wolves (bona-fide Canis lupus, morphologically and ecologically indistinguishable from other wolves), as domestic dogs, or as something of their own?
It’s possible that the ancestral population of wolves, from which domestic dogs descend, had golden fur (which some northern wolves sometimes have today) - here’s an interesting read on the topic. This would help explain why feral dogs tend to revert to a baseline of yellow-to-tan fur (as you mention with feral pigs and others that often return to wildtype-colouration).