Diversity-dependence and the role of competition in clade diversification Diversiteitsafhankelijke diversificatie en de macro-evolutionaire rol van competitie
|PhD ceremony:||Mr T.S.C. (Theo) Pannetier|
|When:||January 10, 2023|
|Supervisor:||prof. dr. R.S. (Rampal) Etienne|
|Co-supervisors:||dr. L. Bunnefeld, dr. B. Duthie|
|Where:||Academy building RUG|
|Faculty:||Science and Engineering|
In his thesis, Theo Pannetier studied the implications and methods used to detect diversity-dependence in genealogies of living species (called phylogenies), which contain precious information about the timing of speciation and extinction in their branches.
Pannetier: "Biodiversity is unevenly distributed across the globe – the number of species in tropical regions far exceeds that of temperate regions; and across the tree of life – there are far more species of flowering than non-flowering plants.This is the result of past evolutionary processes, speciation and extinction, and their net balance, diversification.Paleobiologists in the 70s resolved to study whether the relative pace of these events could be explained in terms of high-order rules, i.e., macro-evolutionary processes. From observations of fossil data, they theorised that the growth of diversity itself limited further diversification, as more species implies more intense competition for resources. That is, diversification is diversity-dependent.
In this thesis, I studied the implications and methods used to detect diversity-dependence in genealogies of living species (called phylogenies), which contain precious information about the timing of speciation and extinction in their branches. A first finding we made is that existing method cannot distinguish a phylogeny simulated with a diversity-dependent process from one simulated with a similar process that produces the same expected growth, but without reference to diversity. That is, diversity-dependent diversification does not leave, in itself, a distinctive signature in the branches of phylogenies.Simulating species diversification emerging directly from competition between individuals, we then found that the simple functions currently used to model diversity-dependence are only consistent with a driving role of competition thanks to extinction erasing important information about the early speciation and extinction events."