Tue 16 Apr, guest seminar. Adaptive radiation on oceanic islands: Isolation and connection, repeatability and serendipity by Rosemary Gillespie

Photo: ourenvironment.berkeley.edu

Adaptive radiation on oceanic islands: Isolation and connection, repeatability and serendipity

  • Date and time: Tuesday 16.04.2024 at 10:00
  • Speaker. Dr. Rosemary Gillespie (UC Berkeley)
  • Place: Seminar room K1/K2, Biologen blokk A

Adaptive radiation is one of the key drivers of species diversity, yet the mechanism through which it is achieved, and the outcome of the process, are largely unknown. In many lineages, initial divergence results from environmental or sexual selection leading to divergence of species between environments and subsequent secondary contact. In other lineages, initial reproductive isolation may be achieved without divergent selection; here, ecological niche divergence can develop as a result of interactions between close relatives during secondary contact. The Hawaiian archipelago – in which each island provides a snapshot in time of the evolutionary process – is one system that can offer insights into the processes of adaptive radiation, allowing the early stages of radiation to be studied in real time. Focusing on spiders, I identify lineages in which the abiotic environment appears to play the dominant role in adaptive diversification, with repeated and convergent evolution of sets of taxa adapted to similar sets of environmental conditions. In contrast, divergence in other lineages appears to be the result of character displacement associated with direct interaction between close relatives, leading to convergent evolution of niche-specialized ecomorphs within a given environment. I will discuss the potential role of hybridization, and lack thereof, in facilitating convergence to similar sets of divergent species on different islands.


Best regards,


Dimitar Dimitrov, PhD

Associate Professor

Department of Natural History, University Museum of Bergen, University of Bergen

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