How do you differentiate an event that is very improbable and so takes a billion years from an event that is inevitable, but requires many prerequisites, and so takes a billion years?
The article seems to simply assume the former model ("We assume that once an evolutionary transition is possible (i.e., once the previous transition has occurred), it occurs at a constant average rate λi, so that each ti is exponentially distributed with an expected transition time of βi = 1/λi"), but that feels unjustified to me. Is it really the case that the transition from prokaryote to eukaryote was equally likely at any time, and things simply sat stagnant for a billion years until one day life got lucky?
The article seems to simply assume the former model ("We assume that once an evolutionary transition is possible (i.e., once the previous transition has occurred), it occurs at a constant average rate λi, so that each ti is exponentially distributed with an expected transition time of βi = 1/λi"), but that feels unjustified to me. Is it really the case that the transition from prokaryote to eukaryote was equally likely at any time, and things simply sat stagnant for a billion years until one day life got lucky?