These survivorship curves are shown in figure 6 where four runs of our model are displayed. The exponential decay in the number of survivors is closely related to the monotonous drift that the system experiences towards the extinction threshold, due to the constant change of connections to random values. We do not need to seek for a special external explanation for the episodic decay. Obviously, an external cause can trigger a large extinction event by altering the network dynamics at the critical state. In our approach, the theoretical problems derived from the Red Queen interpretation simply do not arise.
Extinctions are an unavoidable outcome of network dynamics.
Though some selection of connections is present after each extinction event, unpredictability always increases. As with the example of the large blue butterfly, a given species cannot predict how the other players will modify their intrinsic properties and in particular how the network will be rearranged after a new extinction. This situation is basically shared by all the players, and so all of them are, on average, equally prone to disappear in the long run.