Títol: Fossils and Molecules to understand the colonisation of land by arthropods Animal life has marine origins, with only few phyla completing their entire life cycle outside water. The process through which organisms adapt to life on land is known as terrestrialisation, and it is one of the most extreme cases of adaptation. Arthropods and its sister lineage, velvet worms, appeared early in the Cambrian, as the fossil record suggests, and have reached the land anciently and at least in four independent instances (the three of Arthropods: Hexapoda, Myriapoda and Arachnida, + velvet worms). The fact that they colonised the land multiple times independently allow rigorous comparison of the alternative solutions adopted by the different groups to the same adaptive challenge. In this talk I will present the methods used and some of the results I got so far addressing how and when these lineages terrestrialized. Basically, I implemented a molecular palaeobiological approach, where molecular data from living organisms is combined with fossil data to understand changes through time within the context of deep time. Moreover, I will explain the approach we are currently trying to implement at the UB to study the recent colonisation of Canary islands by Dysdera spiders, in which we are trying to retrieve and add molecular markers from low-coverage genomes into phylogenomics matrices, therefore allowing to use samples from collections and museums. Ponent: Jesús Lozano Fernández, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals de la UB. Idioma vehicular: anglès. Lloc: sala d’actes del Castell dels Tres Dragons (Laboratori de Natura, pg. Picasso, s/n) Dins el programa de Seminaris de Biodiversitat, SEMBIO. Debat i intercanvi d’experiències essencialment sobre sistemàtica, zoologia, evolució animal i filogènia molecular. Aquestes xerrades estan organitzades pel Grup de Recerca Consolidat ZooSysEvo format per científics de la Facultat de Biologia (UB) i del Museu de Ciències Naturals de Barcelona. L’objectiu és difondre els continguts de la recerca d’investigadors del grup o d’algun investigador convidat.