Landmark-Based Geometric Morphometrics: What Fish Shapes Can Tell Us about Fish Evolution

 

Tested Studies in Laboratory Teaching, 2013, Volume 34

Peter J. Park, Windsor E. Aguirre, Deborah A. Spikes, & Joan M. Miyazaki

Abstract

Students learn how to apply landmark-based geometric morphmetric techniques to compare lake samples of the threespine stickleback fish (Gasterosteus aculeatus) from Cook Inlet, Alaska. The stickleback is an excellent model organism to teach natural selection, adaptation, and speciation. It is ancestrally a marine or sea-run fish. Innumerable freshwater populations have evolved from these sea-run forms and exhibit specializations to freshwater habitats that range from shallow, structurally complex lakes with benthic-foraging stickleback, to deeper, structurally simple lakes with open-water planktivorous stickleback. Body shapes of benthic and planktivore stickleback are analyzed using free Tps-series software. Landmark digitization and shape analysis are emphasized.

Keywords:  fish, threespine stickleback, morphometrics, body shape, foraging morphology

University of North Carolina, Chapel Hill (2012)