KINET'OGEN'ESIS (from Uk. Kum-rot, kine tos, movable + ylvEcra, genesis, origin, from 717vecrOat, gignesthui. to become). The mechan ics of evolution. Spencer led the way to these studies by his of the mechanical origin of the segmentation of the body in vertebrates, lead ing to the formation of vertelaw. Wyman (1A57) showed that the cancellated structure of the bones of the head, of the thigh-bone, and in other bones is peculiar to man, having a definite relation to his erect position. The bony fibres forming the eancellated structure are like studs or braces. Cope, and also Ryder, have discussed the mold ing of the as the result of mechanical strains. and the shape of the teeth is due to mechanical strains and imparts.
The direct evidence in favor of the kincto genetic mode of evolution is greatly strengthened by the discovery by Ameghino, in the Tertiary heels of the Argentine Republic, of one-toed ungu lates with two splint bones and with teeth strik in,71;m like those of the horse, though belonging to a quite different order. The similarity or con
vergence in shape is due to the action of similar mechanical conditions in two quite unrelated groups. The results of strains involved in dig ging are seen in the fore legs of the mole, of the fossorial edentates:, and the mimic-crickets. Thus, as Cope concludes. in biologic evolution as in ordinary mechanics, identical causes produce identical results.
Consult: Wyman, "On the Cancellated Struc ture of Some of the Bones of the Human Body," in the Jourfm/ of the Boston Society of Natural History, vol. vi. (Boston. 1857); Cope, The Eri mnry Fnetors of Organic Erolution (Chicago, 1896). See EvoixTioN; USE-INIIERITANcE.