In a cladistic analysis, any taxon used to help resolve the polarity of characters, and which is hypothesized to be less closely related to each of the taxa under consideration than any are to each other.
A group to which a person does not belong and toward which the person may feel a sense of competitiveness or hostility.
A taxon that separated from another taxon, whose lineage is to be inferred, before the latter underwent evolutionary radiation.
A social group with which one does not identify or to which one does not belong.
a closely related group of several species (if possible), generally showing only the apparently plesiomorphic states
a group of sequences which were selected to root the tree
a group that lies outside the group whose phylogeny is being analyzed
an organism that is very closely related to the organism under study
a species or group of species that is relatively closely related to the study group (ingroup), but not as closely related as any study-group members are to each other
one or, preferably, several taxa that lie outside the group of interest, that is the group in which we are trying to detect relationships. For example, if we are interested in determining the relationships of minnows, we would use the closest relatives of minnows as our outgroups. Outgroup comparison is the way we determine how widespread a particular feature may be, whether it is found only within the group of interest, or beyond that group. The sister taxon to the ingroup.
(Paleoanthropology) A species not being analysed. the ones that are shared are primitive.
Any group with which a person does not share membership.
A species or group of species that is closely related to the group of species being studied, but clearly not as closely related as any study-group members are to each other. ovarian cycle(oh- vair-ee-un) The cyclic recurrence of the follicular phase, ovulation, and the luteal phase in the mammalian ovary, regulated by hormones.
A terminal taxon (or group of taxa), preferably the sister-group of the ingroup, that is used to root a cladogram (cf. ingroup). The root is placed between the outgroup(s) and the ingroup. Multiple outgroups may be used.
A species or a set of species that is the least related to the others in a group of species.
In cladistics, a taxon, not a member of the group under study, which is used to fix the polarity of character states. Cladistics without an outgroup yields a shortest path between species, but does not say where the path begins -- where the root of the phylogenetic tree is. The outgroup comparison roots the tree. Typically, the outgroup is a taxon just basal to the group under study and is assumed to have all characters in the primitive state. In essence, the outgroup is used as a proxy for the last common ancestor of the group (assuming the group turns out to be monophyletic within the limits of the study). This assumption need not be completely accurate. However, the degree to which the outgroup differs from the hypothetical ancestor obviously introduces an error of essentially unknown size and requires some assumptions about the phylogeny of the outgroup itself. Example: Panderichthys in a study of early tetrapods.
One or more taxa considered to be outside the monophyletic group of interest.
In cladistics, an outgroup is a (monophyletic) group of organisms that serves as a reference group for determination of the evolutionary relationship among three or more monophyletic groups of organisms.
Wholesaler
