∞ generated and posted on 2015.12.27 ∞
Organisms that are progenitors to a given population but which do not possess an overlapping gene pool.
|An Ancestor Species is simply an older species that serves as an ancestor to a more recently living species.|
The separation of gene pools is essentially the definition of speciation, at least in terms of the biological species concept. An ancestral species therefore is a species that a given species descended from, but which otherwise is not simply a past population that is part of the same species.
Note that these ideas are complicated by our inability to test the ability of fossil species to successfully mate, and hence other species concepts often must be invoked other than the biological species concept. Compare with descendant species.
Given that the fossil record is an imperfect representation of what species existed in the past, it is considered to be unlikely that all ancestral species associated with a given species will be known. Furthermore, the assignment of ancestral species is always tentative since a given, extinct species might represent a close relative of the true ancestral species rather than the ancestral species itself.
Note that this tentative nature of assignment of ancestor-descendant relationships is an important aspect of what the science of paleontology is all about.