12:00 PM - 12:15 PM
[BCG09-06] Neutral stochastic model of evolution and biodiversity: topological approach to phylogenetic tree
Keywords:molecular phylogenetic tree, topological property, Horton analysis, bifurcation ratio, Neutral stochastic model, biodiversity
Data used in this paper are as following vertebrata: spiny-rayed fishes (Near et al., 2013), amphibian (Frost et al., 2006), turtles (Grawford et al., 2015), squamata (Pyron et al., 2013), avian (Burleigh et al., 2015) and placental mammals (Murphy et al., 2001). We applied the Horton analysis to these data and show that the Horton’s first law is valid in the molecular phylogenetic, and the mean value of the bifurcation ratio is estimated to be about 3.2. The value 3.2 is lower than the theoretical value: about 4.0 estimated by previous studies (e.g., Leopold and Langbein, 1962; Shreve, 1967). The causes of this are assumed as follows: (1) The bifurcation ratio of the molecular phylogenetic tree includes the effect of the non-neutral stochastic process. (2) The result of the joint model is different from that of the branch model. Then we perform the neutral stochastic simulation of the branching with the two parameters: branching probability and time span. As a result, the value of the bifurcation ratio is found to be 3, which is very close to the date value 3.2. This means that the topological property of the molecular phylogenetic trees reflects the neutral stochastic process in evolution and biodiversity. In other words, the topological properties of the tree can be understood without the endemic events in Earth history.