Originally, as narrated in a recent history of the field,2 physiology focused primarily on human beings, in large part from a desire to improve medical practices. When physiologists first began comparing different species it was sometimes out of simple curiosity to understand how organisms work but also stemmed from a desire to discover basic physiological principles. This use of specific organisms convenient to study specific questions is known as the Krogh Principle.
C. Ladd Prosser,3 a founder of modern comparative physiology, outlined a broad agenda for comparative physiology in his 1950 edited volume (see summary and discussion in Garland and Carter4):
1. To describe how different kinds of animals meet their needs.
2. The use of physiological information to reconstruct phylogenetic relationships of organisms.
3. To elucidate how physiology mediates interactions between organisms and their environments.
4. To identify "model systems" for studying particular physiological functions.
5. To use the "kind of animal" as an experimental variable.
Comparative physiologists often study organisms that live in "extreme" environments (e.g., deserts) because they expect to find especially clear examples of evolutionary adaptation.9 One example is the study of water balance in desert-inhabiting mammals, which have been found to exhibit kidney specializations.10
Similarly, comparative physiologists have been attracted to "unusual" organisms, such as very large or small ones. As an example, of the latter, hummingbirds have been studied. As another example, giraffe have been studied because of their long necks and the expectation that this would lead to specializations related to the regulation of blood pressure. More generally, ectothermic vertebrates have been studied to determine how blood acid-base balance and pH change as body temperature changes.
In the United States, research in comparative physiology is funded by both the National Institutes of Health and the National Science Foundation.
A number of scientific societies feature sections on comparative physiology, including:
Knut Schmidt-Nielsen (1915–2007) was a major figure in vertebrate comparative physiology, serving on the faculty at Duke University for many years and training a large number of students (obituary). He also authored several books, including an influential text, all known for their accessible writing style.
Grover C. Stephens (1925–2003) was a well-known invertebrate comparative physiologist, serving on the faculty of the University of Minnesota until becoming the founding chairman of the Department of Organismic Biology at the University of California at Irvine in 1964. He was the mentor for numerous graduate students, many of whom have gone on to further build the field (obituary). He authored several books and in addition to being an accomplished biologist was also an accomplished pianist and philosopher.
Prosser, C. L. (1975). "Prospects for comparative physiology and biochemistry". Journal of Experimental Zoology. 194 (1): 345–348. Bibcode:1975JEZ...194..345P. doi:10.1002/jez.1401940122. PMID 1194870. /wiki/Bibcode_(identifier) ↩
Anctil, Michel (2022). Animal as machine - The quest to understand how animals work and adapt. Montreal & Kingston: McGill-Queen's University Press. ISBN 978-0-2280-1053-1. 978-0-2280-1053-1 ↩
Greenberg, M. J.; P. W. Hochachka; C. P. Mangum (1975). "Biographical data: Clifford Ladd Prosser". Journal of Experimental Zoology. 194 (1): 5–12. Bibcode:1975JEZ...194....5G. doi:10.1002/jez.1401940102. PMID 1104756. /wiki/Bibcode_(identifier) ↩
Garland, T. Jr.; P. A. Carter (1994). "Evolutionary physiology" (PDF). Annual Review of Physiology. 56: 579–621. doi:10.1146/annurev.ph.56.030194.003051. PMID 8010752. Archived from the original (PDF) on 2021-04-12. Retrieved 2007-02-11. /wiki/Theodore_Garland_Jr. ↩
Mangum, C. P.; P. W. Hochachka (1998). "New directions in comparative physiology and biochemistry: mechanisms, adaptations, and evolution". Physiological Zoology. 71 (5): 471–484. doi:10.1086/515953. PMID 9754524. S2CID 25169635. /wiki/Doi_(identifier) ↩
Conley, K. E.; S. L. Lindstedt (1996). "Rattlesnake tail-shaking: minimal cost per twitch in striated muscle". Nature. 383 (6595): 71–73. doi:10.1038/383071a0. PMID 8779716. S2CID 4283944. /wiki/Doi_(identifier) ↩
Prosser (1950, p. 1) ↩
Al-kahtani, M.A.; C. Zuleta; E. Caviedes-Vidal; T. Garland Jr. (2004). "Kidney mass and relative medullary thickness of rodents in relation to habitat, body size, and phylogeny" (PDF). Physiological and Biochemical Zoology. 77 (3): 346–365. CiteSeerX 10.1.1.407.8690. doi:10.1086/420941. PMID 15286910. S2CID 12420368. Archived from the original (PDF) on 2010-06-17. Retrieved 2009-01-17. /w/index.php?title=Theodore_Garland_Jr&action=edit&redlink=1 ↩