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Seminar by Sebastian Höhna, SU

posted Sep 24, 2012, 2:47 AM by Johan Nylander
Onsdagen den 26 september klockan 15.15 håller Sebastian Höhna, Stockholms universitet, ett seminarium med titeln / On Wednesday September 26 at 15.15, Sebastina Höhna from Stockholm University will give a seminar with the title:

Estimating non-constant species diversification rates and patterns under incomplete, systematic species sampling.

Sammanfattning / Abstact:
The macro-evolutionary process of species diversity is commonly modeled using a birth-death branching process. Here I consider the class of processes where each species alive at time t has the same speciation rate lambda(t) and the extinction rate mu(t). The questions I aim to answer are: Did the rates change over time? How did the rates change over time? Where there times of mass-extinction and/or rapid radiations?

Recent extensions include specific rate functions (e.g. exponential decreasing/increasing) and random species sampling. In this talk I will present the likelihood equations for any time-dependent rate function (e.g. with one or several modes) and systematic species sampling (e.g. one species per family). I will show the estimates of the speciation rate and extinction rate over time for the complete order of mammals. Additionally, I will present a second approach for the derivation of the likelihood which can be used for fast simulation of reconstructed phylogenetic trees for:

a) a fixed time of the process,
b) a fixed number of sampled species and
c) a fixed number of sampled species and time of the process.

Lokal  /  Place: Cramerrummet (rum 306)  /  Cramér room (room 306), hus /  house 6; Kräftriket.