One of the main tasks of modern gerontology is isolation of the group of phenomena essential for aging from epiphenomenona accompanying them. The modern methods of simulation modeling may be the proper tool for correct isolation. The point of their application is reproduction of external aging manifestations in silico, and, in the first place, of standard survival curves with the help of the simplest internal mechanism. Such a mechanism seems to be the prime mover of aging. The aging model of one the most popular objects of experimental biology, a fruit fly Drosophila melanogaster created by us (http://winmobile.biz/moton/moto.html), is based on the assumption that the key mechanism of aging is cellularity loss, the speed of which is determined by the parameters of active oxygen forms generation in motoneurons.