Comparative studies performed at the intraspecific and interspecific level often demonstrate that substantial development of a certain organ is frequently accompanied by the reduction of other organs. In some cases, the reasons for this organ competition are quite obvious. For purely spatial reasons, the males of certain species of beetles of the Scarabaeidae family cannot simultaneously have enormous protuberances on their heads, which they use in battles for females, and eyes of the same size as the females or as males with small protuberances (Emlen 2001). In other cases, the reasons for application of the “trade-off” principle are less apparent and organ competition can occur during allocation of resources during individual development (Wolf et al. 2001). The trade-off principle, applicable in inter-organ competition, can substantially contribute to overall diversity in nature. The individual species necessarily differ in a greater number of traits, where it is probable that species with certain more advanced organs will, on the other hand, have other organs that are poorly developed and suboptimal from a functional viewpoint. This reduces the probability that a certain species would force out all its competitors in a particular environment through its attained level of anagenesis.