"If, however, one factor is too successful, it will continue to be the winning factor regardless of the variation in the other factors over the range of variation in the conditions, and therefore will stifle the development of other advantageous factors until the conditions change sufficiently that it no longer is the winning factor. At this point, the whole population is ill prepared for the change, and may well perish entirely if the winning factor accidentally becomes the matching factor for a disease or a predator."