木瓜福利影视

Current projects

Fossils are the best archive to document past biodiversity of higher organisms and their adaptations to environmental changes. Following a tradition dating back to Darwin, biologists have regarded the fossil record as too full of gaps to be used for reconstructing evolution. MindTheGap will break through this limitation by applying state-of-the-art knowledge of how the geological record forms: today we know that it is not a random selection of snapshots from the past, but a complex, yet systematic outcome of sedimentological processes that can be modelled mathematically. I will constrain how gaps in the record of Earth鈥檚 history distort reconstructions of evolution and lead an interdisciplinary team to create a toolbox that will 1) identify gaps in the geological record and 2) account for them in evolutionary trees.

Stratigraphic models will allow me to predict the distribution of gaps in the 10³-10⁵ years range, which cannot be detected using dating methods available to geologists but are the most relevant to evolution at the species and population levels. Originations and extinctions happen not only in time, but also in space, I will therefore use 3D models of stratigraphic architectures, which describe completeness across environments. My preliminary work shows that incorporating information on incompleteness in Bayesian evolutionary reconstructions improves them fundamentally. MindTheGap will, for the first time, tap into the wealth of spatial and temporal information preserved in the rock record, with all environmental information that can be reconstructed from it. It will allow us to bridge the gap between evolution at the timescale of human observation and macroevolutionary processes preserved through fossils.

This project, funded by the European Research Council Starting Grant programme, started in February 2023, and involves Niklas Hohmann (PhD student) and Xianyi Liu (postdoc, starting in July 2023). MindTheGap is carried our in collaboration with the .

External project collaborators:

• David De Vleeschouwer, 木瓜福利影视 of M眉nster
• Rachel Warnock, Friedrich-Alexander-Universit盲t Erlangen-N眉rnberg
• Peter Burgess, 木瓜福利影视 of Liverpool
• Theresa Nohl, Vienna 木瓜福利影视

Conservation paleobiology of toothed whales of the North Atlantic

Whales are critical organisms in the Earth鈥檚 ocean ecosystems. Increased shipping, the construction of off-shore wind farms and rising sea temperatures have decimated their populations. Because whales have long lifespans and migrate over large areas, we do not have an ecological baseline to evaluate their population dynamics and shrinking of habitats. Such information is, however, available in the historical (the last few centuries old) and fossil whale remains in the North Sea. 

This project previously involved Shirin Nurshan Rahman as a PhD student and Jeroen Kievet, Natasha Tfanakchi and Ja毛l B茅r茅nos as BSc students.

Past projects

Turing or Milankovitch? Are sedimentary rhythms self-organized or astronomically forced?

This project, awarded to me by the in the Small-Scale Initiatives in Software Performance Optimization programme, was carried out in 2022. We addressed the question: when can chemical-self organization in sediment be confused with astronomical forcing of the palaeoclimate? Rhytmic changes in lithology are commonly used to reconstruct palaeoclimate and highly-resolved timescales in the Earth's history, but there is a risk that such rhytmites arise through chemical self-organization, with no or little allogenic input (; ). The chemical reactions are similar to those known as Turing patterns. In this project we collaborate with software engineers from the Netherlands eScience Center in implementing the model of chemical self-organization conceptualized by Prof. Ivan L'Heureux at Ottawa 木瓜福利影视. The first part of the project was developing a stable implementation that could be shared and used with the community. You can read .

Collaborators in this project: Hanno Spreeuw and Johan Hidding (), Niklas Hohmann (Utrecht 木瓜福利影视), Theresa Nohl (Vienna 木瓜福利影视), Frits Hilgen (Utrecht 木瓜福利影视).

Ultrastructural evolution of the first vertebrate skeletal tissues - reconstruction using electron backscatter diffraction (EBSD)

The vertebrate mineralized skeleton is among the most successful innovations in the history of life. Its properties allowed for the development of an astounding diversity of biomechanical strategies, including locomotion, food processing, predation, and body armour, stimulating major diversification episodes. The composite hydroxyapatite-organic structure of vertebrate skeletal tissues has also served as an inspiration for engineered medical materials. The understanding of the relationship between the ultrastructure and functional properties in these tissues is currently derived almost exclusively from mammal teeth. The mammalian teeth model, however, does not represent the full breadth of structures present in the earliest vertebrate hypermineralized tissues. A model linking their structure and function is needed in order to test hypotheses on their functional adaptations. This, in turn, requires a method allowing to characterise individual crystals and crystal domains quantitatively. In calcareous skeletons, this has been achieved using electron backscatter diffraction (EBSD), but attempts to employ this technique to hydroxyapatite tissues have been unsuccessful so far. We developed allowing to apply EBSD to the earliest vertebrate hypermineralized tissues. We focussed on conodonts, a fossil group which has developed hypermineralized skeletal tissues for the first time among vertebrates and in parallel to other groups. tested a previously proposed hypothesis that conodont crown tissues show ultrastructural adaptations to food-processing functions and the broad ultrastructural variation manifested in these adaptations is made possible through modifications of sizes and orientations of crystals and entire crystal domains at several levels of organization. In order to assess diagenetic alternation of crystallographic patterns, we employed Raman spectroscopy in collaboration with Helen E. King.

This project was awared to me by the at Friedrich-Alexander-Universit盲t Erlangen-N眉rnberg and involved Bryan Shirley as a PhD student, who successfully defended his thesis in 2023.