Time-dependent extinction rate and species abundance in a tangled-nature model of biological evolution

Abstract

We present a model of evolutionary ecology consisting of a web of interacting individuals, a tangle-nature model. The reproduction rate of individuals characterized by their genome depends on the composition of the population in genotype space. Ecological features such as the taxonomy and the macroevolutionary mode of the dynamics are emergent properties. The macrodynamics exhibit intermittent two-mode switching with a gradually decreasing extinction rate. The generated ecologies become gradually better adapted as well as more complex in a collective sense. The form of the species abundance curve compares well with observed functional forms. The model's error threshold can be understood in terms of the characteristics of the two dynamical modes of the system.

Network properties, species abundance and evolution in a model of evolutionary ecology

“…Since the maximum number of genotypes in our model is only around 10 6 anyway, the single site species approach is more appropriate. This is perhaps not so unreasonable since any two gene sequences differ by at least 5%; since L ¼ 20: We have been able to extend the initial results obtained in Hall et al (2002) and can consider the evolution of the SAD for high and low y integrated across all 500 runs, as seen in Fig. 5.…”

“…Here, we briefly describe the structure and dynamics of the Tangled Nature model Hall et al, 2002). An individual is represented by a vector S a ¼ ðS a 1 ; S a 2 ; .…”

“…Gaining an understanding from observations is also problematic since laws may very well only be recognizable at the level of averages, see (Loreau and Hector, 2001;Yedid and Bell, 2002). Here, we approach these issues within the framework of a simple individualbased model of ecosystem assembly and evolution Hall et al, 2002;diCollobiano et al, 2003).…”

Unified “micro”- and “macro-” evolution of eco-systems: self-organization of a dynamic network

“…Therefore, it is desirable to have a "unified" theoretical model that would unfold the natural continuous process while simulated on a computer. Very recently, attempts have been made by several groups to merge population dynamics and "macro"-evolution within a single mathematical framework [7,8,15,16,17,18]. These efforts may have been made feasible, at least in part, because of the availability of fast computers.…”

Computer simulations of history of life: speciation, emergence of complex species from simpler organisms, and extinctions

“…This dream has now come closer to reality, mainly because of the availability of fast computers [21,22,23,24,25,26]. It has become feasible now to carry out computer simulations (in-silico experiments) of eco-system models where, each time step would correspond to typical times for "micro"-evolution while each of the simulations is run long enough to capture "macro"-evolution.…”