Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

The variation in the rates of extinction in the individual periods is so large that it is completely impossible for it to be caused by a random fluctuation around a certain average value (Raup 1994).It is obvious that there must have been some other factor that was responsible for the sudden increase in the extinction rate.Fundamentally, there are apparently only two basic causes, exogenic, originating in changes in the environment in which the organisms live, and endogenic, originating in the mutual interactions amongst the organisms living in a particular territory.There are good reasons for assuming that exogenic causes tended to be of key importance.When the time course of extinction was compared in various types of ecosystems, it was found that changes occurred in almost all the ecosystems simultaneously (Raup & Boyajian 1988).It is, of course, quite possible that a change in a certain ecosystem would “run over” into another ecosystem.However, it is not clear how this could affect a greater number of ecosystems and simultaneously how this could occur in geographically separated ecosystems, frequently on a global scale.It is far more probable that the substantial changes in all the ecosystems were caused by some external factor that acted on the entire global ecosystem at the given moment.