While the traditional model of paleontology, the phylogenetic model, posits that features evolved slowly without any direct association with speciation, the relatively newer and more controversial idea of<unk>  equilibrium claims that major evolutionary changes don't happen over a gradual period but in localized, rare, rapid events of branching speciation.<unk>  is considered to be a variation of these models, lying somewhere in between the phyletic<unk>  model and the<unk>  equilibrium model. It states that speciation is not needed for a lineage to rapidly evolve from one equilibrium to another but may show rapid transitions between long-stable states.
Punctuated gradualism
Affective spectrum
Modic changes
Stereotypy
Skew deviation
Hyperintensity
Baricity
Threshold expression