Meeting Abstract

5.6  Saturday, Jan. 4 09:15  The Effects of Diet, Ecology, and Physiology on the Evolution of Endothermic Gastrointestinal Tract Lengths LINSCOTT, T.M.*; ROCHE, E.; BONETT, R.M.; University of Tulsa; University of Minnesota; University of Tulsa mason-linscott@utulsa.edu

Vertebrates have diversified into a wide range of habitats, and consume many forms of organic material. Consequently, vertebrates have evolved many morphological and physiological adaptations to maximize digestive efficiency. As the primary site of nutrient uptake, the intestine’s size has been proposed to be influenced by metabolic demands, diet, and locomotory restrictions [lifestyle]. We tested for the effect of these factors amongst birds and mammals using a phylogenetically informed approach. Diet was found to affect large intestine length in birds and mammals but not small intestine length. Lifestyle influenced small and large intestine length in both birds and mammals, supporting the notion that restrictions are placed on all endotherms intestinal lengths according to the substrate they locomote within or on. Metabolism had an effect on small intestine length but not on large intestine length in mammals. Metabolic rate had no effect on any intestine length measurements within birds, indicating that birds may have other mechanisms to accommodate elevated basal metabolic rate. Our analyses show the relative importance of these factors on the evolution of the gastrointestinal tract of endotherms.