(From www.phylogenomics.se/News)
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. Karta/Directions: http://www.su.se/english/about/campus/maps/kraftriket