If chickens only descended from red junglefowl 8,000 years ago, that is a blip on the evolutionary timescale, which is a process taking millions of years. For comparison, horses and donkeys which can still breed and make mules, diverged 4 million years ago.
The offspring of chickens and RJF are able to reproduce and there are people worried that interbreeding with chickens will have problems for the wild population. But if this is the case, why are they considered separate species instead of the junglefowl just being considered a wild chicken?
In: Biology
Domestication and the accelerated rate of selective breeding that comes with it drastically changes the “evolutionary scale”.
It’s like a cheat code.
Interbreeding isn’t the determining factor in taxonomic speciation.
Domestic dogs and horses, both of which have been at mankind’s side for a very long time, are merely subspecies of their feral forebears.
And that’s the exact same situation the domestic chicken is in. *Gallus gallus domesticus*
Also, domestic chickens have been genetically influenced by grey junglefowl and green junglefowl along the way, so they’re not pure red junglefowl.
Species are a bit of a subjective concept as there is no hard seperation between species, subspecies and close relatives. American Bison and European Wisent can breed just fine, even domestic cows and bison work well. As behavior, habitat and life history of all these animals is significantly different we can be sure to say they are different species.
The same thing goes for junglefowl. They look different from the domestic chicken, their behavior is different and the enviorment is different enough to call them a different species. Chickens have been isolated for the better part of 8 millenia from their wild relatives and have been purposefully bred to be different. This makes the chicken phenotype very different but a lot of the genes that make wild jungle fowl the way they are, wild traits and diversity to resist disease and shifting enviorments, will be lost if they breed with domestic flocks. Domestic species have generally been bottlenecked. Meaning a small group of animals is the ancestor of all domestic animals. This means they are less diverse geneticly then their wild relatives even if they have very diverse looks.
Another part about species is that the concept is a scientific tool. It works as a concept and in our language it works well to divine things but there is no hard border.
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