CEES Friday seminar: Why are there so many types of killer whale, but only one species?

By Andy Foote from NTNU, Norway


Ecotype formation can be a precursor to speciation and thus represents an important, but often neglected stage in the formation of biodiversity. The marine environment is particularly rich in disparate ecotypes, encompassing a wide range of taxonomic groups and is characterised by patchy habitat and prey distribution, but also high dispersal potential and low cost of movement. These opposing characteristics provide increased opportunity for the colonisation of, and local adaptation to, novel ecological niches, whilst constraining divergence across the spatial scale of dispersal. Additionally, intrinsic drivers may influence the progression towards speciation. Linkage disequilibrium (LD) between alleles at loci associated with endogenous reproductive isolation and alleles at loci associated with local adaptation to the environment can be a key progression towards ecotypes becoming reproductively isolated species. Counteractively, recombination can constrain speciation by breaking down LD between loci that promote isolation. Most of the distinctive ecotypes of killer whale studied to date show evidence of some permeability to gene flow from other killer whale populations. Therefore, as argued by Felsenstein (1981), gene flow and recombination of different ancestries gradually erodes linkage disequilibrium between barrier loci to gene flow. Thus, the process of speciation may be prolonged in the marine environment, or the ecotype stage may be the default taxonomic status beyond which many taxa fail to progress.


Andrew Foote, Associate Professor
Department of Natural History, NTNU University Museum
Foote's profile page at NTNU.

Please note

Please note that Andy Foote is visiting us here at IBV/CEES and this seminar will take place in person in Kristine Bonnevies Seminar Room 3508. In addition we will provide a ZOOM link for those who cannot attend in physically. The zoom link has been shared through the CEES seminar mailing list. UiO. Contact us if you would like to be forwarded the invitation e-mail or to subscribe to the list. (Contact Tore Wallem). UiO users can access the Zoom meeting details at this page.

Published Feb. 11, 2022 12:39 PM - Last modified Feb. 11, 2022 12:39 PM