Biosciences Seminar Series - Winter 2019
07 February 2019 - 1pm - Zoology Museum
Digestive adaptations to aerial lifestyle: bats are birds
Prof Ariovaldo Pereira da Cruz Neto
Our Biosciences Seminar Series resumes for the winter term and we are delighted to welcome Prof Ariovaldo P. Cruz-Neto from the Laboratory of Ecological and Evolutionary Physiology at the Department of Zoology at the State University of São Paulo in Rio Claro (Brazil). Neto is an ecological and evolutionary physiologist (e.g. see here for his recent book), with research focussing especially on bats, rodents and birds.
Abstract
In vertebrates, powered flight independently evolved in three lineages: bats, birds and in the extinct pterosaurs. Powered flight is an expensive mode of locomotion and requires extensive, and intertwined, modifications in the respiratory, circulatory and digestive systems. To what extent such modifications reflects phylogenetic constraints or are special cases of convergent evolution is an interesting question. Phylogenetic constraints seem to operate at the level of respiratory system. However, bats shows optimization of some elements of the respiratory system that are thought to enhance its capability for gas exchange. Bats and birds showed convergence in some aspects of the circulatory system and in the muscle capillary network.
In this talk I provide evidences for convergent evolution between birds and bats at the level of digestive system. Due to the burden placed by carrying excess mass when flying, birds and bats evolved intestines with smaller mass and smaller nominal surface area than non-flying mammals (NFM). In principle, such reduction in gut size would be maladaptive, as it decreases food transit time and could potentially jeopardize digestive capacity. However, digestive efficiency in bats and birds are remarkably similar to that of NFM. The reliance on paracellular route for nutrient uptake convergently evolved in bats and birds to overcome this potential trade-off. Although data are still scant, the mechanistic basis associated with a high reliance of the paracellular pathway seems also to converge between birds and bats. Thus, at the level of the adaptations of digestive system associated with the evolution of powered flight, bats are birds!
In this talk I provide evidences for convergent evolution between birds and bats at the level of digestive system. Due to the burden placed by carrying excess mass when flying, birds and bats evolved intestines with smaller mass and smaller nominal surface area than non-flying mammals (NFM). In principle, such reduction in gut size would be maladaptive, as it decreases food transit time and could potentially jeopardize digestive capacity. However, digestive efficiency in bats and birds are remarkably similar to that of NFM. The reliance on paracellular route for nutrient uptake convergently evolved in bats and birds to overcome this potential trade-off. Although data are still scant, the mechanistic basis associated with a high reliance of the paracellular pathway seems also to converge between birds and bats. Thus, at the level of the adaptations of digestive system associated with the evolution of powered flight, bats are birds!
Hope to see many of you - everyone most welcome to attend!
For the list of forthcoming seminars see here
For the list of forthcoming seminars see here
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