ADAPTATION IS THE BASIS FOR BIODIVERSITY Peter J. Park THE MODEL SYSTEM: THE THREESPINE STICKLEBACK (Bell 1995) Please watch Youtube video: http://youtu.be/dUQgj49dtWY The founding of derived, freshwater populations: • Migratory, breeding sea-run fish can get into lakes. • If lake then becomes land-locked, then a derived freshwater population is borne, founded by these sea-run fish. • Along opposite ends of a continuum of lake types are shallow lakes and deep lakes. • In these lakes, anatomical changes in fish from derived freshwater populations is driven by what they eat. • Shallow lakes are dominated by large benthic invertebrates benthic stickleback • Deep lakes do not have benthic invertebrates, making smaller plankton the predominant food source planktivorous stickleback 1 ADAPTATION IS THE BASIS FOR BIODIVERSITY 2 Peter J. Park ADAPTATION IS THE BASIS FOR BIODIVERSITY Peter J. Park (Aguirre 2009) Ecotype - describes a genetically distinct geographic variety or population within species (or among closely related species), which is adapted to specific environmental conditions - Benthic ecotype - Planktivorous ecotype Allopatric ecotypes – only one of the stickleback ecotypes is found in a lake Sympatric ecotypes – both ecotypes are found in the same lake. 3 ADAPTATION IS THE BASIS FOR BIODIVERSITY Peter J. Park Hybrids between sympatric benthics and planktivores have poor survival (Gow et al. 2007). ----------------------------------------------------------------------------------------References Aguirre, W.E. 2009. Microgeographical diversification of threespine stickleback: body shape–habitat correlations in a small, ecologically diverse Alaskan drainage. Biological Journal of the Linnean Society 98: 139–151. Bell, M.A. 1995. Intraspecific systematics of Gasterosteus aculeatus populations: implications for behavioral ecology. Behaviour 132: 1131-1152. Coyne, J.A. & H.A. Orr. 2004. Speciation. Sinauer Associates, Inc. Gow JL, C.L. Peichel, & E.B. Taylor. 2007. Ecological selection against hybrids in natural populations of sympatric threespine sticklebacks. Journal of Evolutionary Biology 20: 2173-2180 Schluter, D. 2001. The Ecology of Adaptive Radiation. Oxford University Press. Programs Free shape analysis software (http://life.bio.sunysb.edu/morph/) tpsUtil tpsDIG2 tpsRelw Free concept map software (http://cmap.ihmc.us/) 4