This includes species which are semi-domesticated, undomesticated but captive-bred on a commercial scale, or commonly wild-caught, at least occasionally captive-bred, and tameable.
In order to be considered fully domesticated, most species have undergone significant genetic, behavioural and morphological changes from their wild ancestors, while others have changed very little from their wild ancestors despite hundreds or thousands of years of potential selective breeding.
A number of factors determine how quickly any changes may occur in a species, but there is not always a desire to improve a species from its wild form.
There are also some species that are extensively commercially used by humans, but are not significantly altered from wild-type animals.
Many animals on this second table are at least somewhat altered from wild-type animals due to their extensive interactions with humans, albeit not to the point that they are regarded as distinct forms (therefore, no separate wild ancestors are noted) or would be unable to survive if reintroduced to the wild.