Cell size is positively correlated between different tissues in passerine birds and amphibians,but not necessarily in mammals |
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Authors: | J Koz?owski M Czarno??ski A Fran?ois-Krassowska S Maciak T Pis |
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Institution: | 1.Jagiellonian University, Institute of Environmental Sciences, Gronostajowa 7, 30-387 Kraków, Poland;2.Department of Vertebrate Zoology, Nicolaus Copernicus University, Institute of Ecology and Environment Protection, Gagarina 9, 87-100 Toruń, Poland;3.Department of Animal Physiology and Histology, University of Białystok, Institute of Biology, Świerkowa 20B, 15-950 Białystok, Poland |
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Abstract: | We examined cell size correlations between tissues, and cell size to body mass relationships in passerine birds, amphibians and mammals. The size correlated highly between all cell types in birds and amphibians; mammalian tissues clustered by size correlation in three tissue groups. Erythrocyte size correlated well with the volume of other cell types in birds and amphibians, but poorly in mammals. In birds, body mass correlated positively with the size of all cell types including erythrocytes, and in mammals only with the sizes of some cell types. Size of mammalian erythrocytes correlated with body mass only within the most taxonomically uniform group of species (rodents and lagomorphs). Cell volume increased with body mass of birds and mammals to less than 0.3 power, indicating that body size evolved mostly by changes in cell number. Our evidence suggests that epigenetic mechanisms determining cell size relationships in tissues are conservative in birds and amphibians, but less stringent in mammals. The patterns of cell size to body mass relationships we obtained challenge some key assumptions of fractal and cellular models used by allometric theory to explain mass-scaling of metabolism. We suggest that the assumptions in both models are not universal, and that such models need reformulation. |
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Keywords: | erythrocytes cellular architecture metabolic rate scaling |
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