Often taxonomists prefer to use phylogenetic analysis to determine whether a population can be considered a subspecies. Phylogenetic analysis relies on the concept of derived characteristics that are not shared between groups, usually applying to populations that are allopatric (geographically separated) and therefore discretely bounded. This would make a subspecies, evolutionarily speaking, a clade a group with a common evolutionary ancestor population. The smooth gradation of human genetic variation in general tends to rule out any idea that human population groups can be considered monophyletic (cleanly divided), as there appears to always have been considerable gene flow between human populations. Rachel Caspari (2003) have argued that clades are by definition monophyletic groups (a taxon that includes all descendants of a given ancestor) and since no groups currently regarded as races are monophyletic, none of those groups can be clades.
What analysis method are taxonomists fond of using in considering a population?
phylogenetic

The devotio was the most extreme offering a Roman general could make, promising to offer his own life in battle along with the enemy as an offering to the underworld gods. Livy offers a detailed account of the devotio carried out by Decius Mus; family tradition maintained that his son and grandson, all bearing the same name, also devoted themselves. Before the battle, Decius is granted a prescient dream that reveals his fate. When he offers sacrifice, the victim's liver appears "damaged where it refers to his own fortunes". Otherwise, the haruspex tells him, the sacrifice is entirely acceptable to the gods. In a prayer recorded by Livy, Decius commits himself and the enemy to the dii Manes and Tellus, charges alone and headlong into the enemy ranks, and is killed; his action cleanses the sacrificial offering. Had he failed to die, his sacrificial offering would have been tainted and therefore void, with possibly disastrous consequences. The act of devotio is a link between military ethics and those of the Roman gladiator.
With what does the devotio link to military ethics?
Roman gladiator

Geologically, West Antarctica closely resembles the Andes mountain range of South America. The Antarctic Peninsula was formed by uplift and metamorphism of sea bed sediments during the late Paleozoic and the early Mesozoic eras. This sediment uplift was accompanied by igneous intrusions and volcanism. The most common rocks in West Antarctica are andesite and rhyolite volcanics formed during the Jurassic period. There is also evidence of volcanic activity, even after the ice sheet had formed, in Marie Byrd Land and Alexander Island. The only anomalous area of West Antarctica is the Ellsworth Mountains region, where the stratigraphy is more similar to East Antarctica.
During what eras was the Antarctic Peninsula formed?
late Paleozoic and the early Mesozoic