Thus, although increased dimensionality of niche divergence may play a causal role in driving phenotypic divergence and progress towards speciation, the role of time in allowing such increased dimensionality deserves further study.
Moreover, because heterochronic patterns are considered to be important possible steps towards speciation [ 9- 11], understanding of the link between SSD and heterochrony is of primary importance.
The contribution of all these different and independent evolutionary events towards speciation and adaptation of thermophilic bacteria of genus Thermus were analysed.
Their results suggest that, contrary to my above prediction, A. inornata seems to have progressed less towards speciation that the other two species.
Diversification into these isoforms may have been initiated by gene duplication, followed by speciation and selection towards opposite needs for protecting copper-dominated metabolic pathways from nonessential cadmium.
Although the mating preferences between white and brown lizards have not yet been documented for those species, Rosenblum and Harmon have since combined data from nuclear and mitochondrial genotyping with morphological assessments to evaluate the progress of each of these ecotypes towards speciation [ 127].
Given this, it is thus not surprising that dioecious species should be guarded against inbreeding via higher mutations loads, and thus have a much lower tendency towards speciation, and thus be much less numerous than those with complete or partial hermaphrodism.
The ecotypes also exhibit partial, but incomplete, progress towards ecological speciation [33], [72], [75] [80].
Population disjunctions, such as vicariant events and limitations to dispersal, are important first steps towards allopatric speciation [ 60].
