is more economically productive is a very serious loss, leading to excessive poverty with increased severity in the action of natural selection, of which some of the Southern States, during the Reconstruction period, offer a good illustration.
Selection is also rendered more intense by the heavy burden of taxation, and in the very common depreciation of currency as is now felt in Russia.
Sexual selection as well as lethal is affected by war in manifold ways. Considering the armed force, there is an inter-group selection, when the enemy's women are assaulted by the soldiers. While this has been an important factor in the past, it is somewhat less common now, with better army discipline and higher social ideals.
Within the group, mating at the outset of a war is greatly increased by many hurried marriages. There is also alleged to be sometimes an increase of illegitimacy in the neighborhood of training camps. In each of these instances, these matings do not represent as much maturity of judgment as there would have been in times of peace, and hence give a less desirable sexual selection.
In the belligerent nation at home, the number of marriageable males is of course far less than at ordinary times. It becomes important, then, to compare the quality of the non-combatants and those combatants who survive and return home, since their absence during the war period of course decreases their reproduction as compared with the non-combatants. The marked excess of women over men, both during the war and after, necessarily intensifies the selection of women and proportionately reduces that of men, since relatively fewer men will remain unmated. This excess of women is found in all classes. Among superiors there are, in addition, some women who never marry because the war has so reduced the number of suitors