Phylogenetic niche conservatism

The term phylogenetic niche conservatism has seen increasing use in recent years^[when?] in the scientific literature, though the exact definition has been a matter of some contention.^[1] Fundamentally, phylogenetic niche conservatism refers to the tendency of species to retain their ancestral traits. When defined as such, phylogenetic niche conservatism is therefore nearly synonymous with phylogenetic signal. The point of contention is whether or not "conservatism" refers simply to the tendency of species to resemble their ancestors, or implies that "closely related species are more similar than expected based on phylogenetic relationships".^[1] If the latter interpretation is employed, then phylogenetic niche conservatism can be seen as an extreme case of phylogenetic signal, and implies that the processes which prevent divergence are in operation in the lineage under consideration. Despite efforts by Jonathan Losos to end this habit, however, the former interpretation appears to frequently motivate scientific research. In this case, phylogenetic niche conservatism might best be considered a form of phylogenetic signal reserved for traits with broad-scale ecological ramifications (i.e. related to the Hutchinsonian niche).^[2] Thus, phylogenetic niche conservatism is usually invoked with regards to closely related species occurring in similar environments.^[3]