Hostname: page-component-857557d7f7-bvshn Total loading time: 0 Render date: 2025-12-09T02:58:55.982Z Has data issue: false hasContentIssue false
  • English
  • Français

Selective factors in the origin of the mammalian diaphragm

Published online by Cambridge University Press:  08 April 2016

John A. Ruben ,
Albert F. Bennett  and
Frederick L. Hisaw
John A. Ruben
Affiliation:
Zoology Department, Oregon State University, Corvallis, Oregon 97331
Albert F. Bennett
Affiliation:
School of Biological Sciences, University of California, Irvine, California 92717
Frederick L. Hisaw
Affiliation:
Zoology Department, Oregon State University, Corvallis, Oregon 97331
Get access Rights & Permissions [Opens in a new window]

Abstract

The origin of endothermic homeothermy and of high metabolic rate in mammals is currently believed to be the result of early (Mesozoic) selection in advanced cynodont therapsids and/or early mammals for either (1) enhanced thermoregulatory capacity or (2) increased powers of endurance and stamina. Selective factors underlying the origin of specialized respiration/ventilation-support systems in mammals are possible indices of the validity of these two hypotheses. One such support structure is the diaphragm, a specialized muscle that facilitates lung ventilation. We tested capacity for maintenance of resting metabolic rate, thermoregulation, and for extended, intense exercise in laboratory rats (Rattus rattus) in which diaphragm function had been completely ablated. The results were virtual elimination of aeroboic scope (active metabolic rate — resting metabolic rate) but resting metabolic rate was unaffected. Thermoregulatory capacity was unimpaired to at least 8° below lower critical temperature. These and other data suggest that the origin of the mammalian diaphragm, as well as mammalian metabolic rates, may have been related to selection for greater levels of sustainable activity rather than for functions associated with thermoregulation.

Information

Type
Articles
Information
Paleobiology , Volume 13 , Issue 1 , Winter 1987 , pp. 54 - 59
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Literature Cited

Alexander, R. M. 1975. The Chordates. Cambridge Univ. Press; Cambridge.Google Scholar
Arey, L. B. 1965. Developmental Anatomy. W. B. Saunders Co.; Philadelphia.Google Scholar
Bennett, A. F. 1972. The effect of activity on oxygen consumption, oxygen debt, and heart rate in the lizards Varanus gouldii and Sauromalas hispidus. J. Comp. Physiol. 81:289–299.Google Scholar
Bennett, A. F. and Ruben, J. 1979. Endothermy and activity in vertebrates. Science. 206:649–654.Google Scholar
Bennett, A. F. and Ruben, J. 1986. The metabolic and thermoregulatory status of therapsid reptiles. In: Roth, J., ed. The Biology and Ecology of Therapsid Reptiles, Smithsonian Inst. Publ.; Washington, D.C.Google Scholar
Bramble, D. M. and Carrier, D. 1983. Running and breathing in mammals. Science. 219:251–256.Google Scholar
Brink, A. S. 1956. Speculations on some advanced mammalian characteristics in the higher mammal-like reptiles. Paleontol. Africa. 4:77–95.Google Scholar
Crompton, A. W., Taylor, C. R., and Jagger, J. A. 1978. Evolution of homeothermy in mammals. Nature. 272:333–336.CrossRefGoogle ScholarPubMed
Eckert, R. and Randall, D. 1983. Animal Physiology. Freeman & Co.; San Francisco.Google Scholar
Gordon, M. S., Bartholomew, G. A., Grinnell, A. D., Jorgansen, C. B., and White, F. N. 1982. Animal Physiology. 4th ed.Macmillan Co.; New York.Google Scholar
Gunderson, H. L. 1976. Mammalogy. McGraw-Hill Book Co.; New York.Google Scholar
Harlow, P. and Grigg, P. 1984. Shivering thermogenesis in a brooding diamond python, Python spilotes spilotes. Copeia. 1984:959–965.CrossRefGoogle Scholar
Hart, J. S. 1971. Rodents. In: Whitton, G. C., ed. Comparative Physiology of Thermoregulation. Vol. 2. Academic Press; New York.Google Scholar
Hill, R. W. 1972. Determination of oxygen consumption using the paramagnetic oxygen analyzer. J. Appl. Physiol. 261–263.Google Scholar
Hopson, J. 1973. Endothermy, small size, and the origin of mammalian reproduction. Am. Nat. 107:446–452.Google Scholar
Jansen, J. Z. 1931. Contributions to the innervation of the diaphragm of a goat. Dissertation, Univ. of Utrecht.Google Scholar
Kemp, J. A. 1982. Mammal-like Reptiles and the Origin of Mammals. Academic Press; New York.Google Scholar
Lillegraven, J. A., Clemens, W. A., and Kielan-Jawerowska, . 1979. Mesozoic Mammals. Univ. Calif. Publ.; Berkeley.Google Scholar
McNab, B. K. 1978. The evolution of endothermy in the phylogeny of mammals. Am. Nat. 112:1–21.Google Scholar
Nagy, K. 1982. Energy requirements of free-living iguanid lizards. In: Burghardt, G. and Rand, A. S., eds. Iguanas of the World: Their Behavior, Ecology and Conservation. Noyes Publ.; Park Ridge, N.J.Google Scholar
Sant'Ambrogio, G., Frazier, D. T., Wilson, M. F., and Agostoni, E. 1963. Motor innervation and pattern of activity of cat diaphragm. J. Appl. Physiol. 18:43–46.CrossRefGoogle ScholarPubMed
Schlaepfer, K. 1926. A further note on the motor innervation of the diaphragm. Anat. Rec. 32:143–150.CrossRefGoogle Scholar
Stahl, B. J. 1974. Vertebrate History: Problems in Evolution. McGraw-Hill; New York.Google Scholar
Strauss, L. H. 1933. Beitrag zur motorischen innervation des Zwerchfelles beim Menschen und bei Tieren. Z. Ges. Exp. Med. 86:244–257.Google Scholar
Taigen, T. 1983. Activity metabolism of anuran amphibians: implications for the origin of endothermy. Am. Nat. 12:94–109.Google Scholar