Comparative physiology

Comparative physiology

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Encyclopedia
Comparative physiology is a subdiscipline of physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 that studies and exploits the diversity of functional characteristics of various kinds of organisms. It is closely related to evolutionary physiology
Evolutionary physiology
Evolutionary physiology is the study of physiological evolution, which is to say, the manner in which the functional characteristics of individuals in a population of organisms have responded to selection across multiple generations during the history of the population.It is a subdiscipline of both...

 and environmental physiology. Many universities offer undergraduate courses that cover comparative aspects of animal physiology. According to Prosser, "Comparative Physiology
is not so much a defined discipline as a viewpoint, a philosophy."

History


Originally, physiology
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 focused primarily on human beings, in large part from a desire to improve medical practices. When physiologists first began comparing different species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 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
Krogh Principle
Krogh's principle states that "for such a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied." This concept is central to those disciplines of biology that rely on the comparative method, such as neuroethology,...

.

Methodology


C. Ladd Prosser, a founder of modern comparative physiology, outlined a broad agenda for comparative physiology in his 1950 edited volume (see summary and discussion in Garland
Theodore Garland, Jr.
Theodore Garland, Jr. is a biologist specializing in evolutionary physiology. He was on the faculty at the University of Wisconsin–Madison for 14 years, served at the National Science Foundation for one year, and is currently Professor of Biology at the University of California, Riverside. He...

 and Carter):

1. To describe how different kinds of animals meet their needs.
This amounts to cataloging functional aspects of biological diversity, and has recently been criticized as "stamp collecting" with the suggestion that the field should move beyond that initial, exploratory phase.


2. The use of physiological information to reconstruct phylogenetic relationships of organisms.
In principle physiological information could be used just as morphological information or DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 sequence is used to measure evolutionary divergence of organisms. In practice, this has rarely been done, for at least four reasons:
  • physiology doesn't leave many fossil
    Fossil
    Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

     cues,
  • it can't be measured on museum
    Museum
    A museum is an institution that cares for a collection of artifacts and other objects of scientific, artistic, cultural, or historical importance and makes them available for public viewing through exhibits that may be permanent or temporary. Most large museums are located in major cities...

     specimens,
  • it is difficult to quantify as compared with morphology or DNA sequences, and
  • physiology is more likely to be adaptive than DNA, and so subject to parallel and convergent evolution
    Convergent evolution
    Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

    , which confuses phylogenetic reconstruction.


3. To elucidate how physiology mediates interactions between organisms and their environments.
This is essentially physiological ecology or ecological physiology.


4. To identify "model systems" for studying particular physiological functions.
Examples of this include using squid giant axons to understand general principles of nerve transmission, using rattlesnake tail shaker muscles for measurement of in vivo changes in metabolites (because the whole animal can be put in an NMR machine), and the use of ectothermic poikilotherms to study effects of temperature on physiology.


5. To use the "kind of animal" as an experimental variable.
"While other branches of physiology use such variables as light, temperature, oxygen tension, and hormone balance, comparative physiology uses, in addition, species or animal type as a variable for each function."
25 years later, Prosser put things this way: "I like to think of it as that method in physiology which uses kind of organism as one experimental variable."


Comparative physiologists often study organisms that live in "extreme" environments
Natural environment
The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....

 (e.g., deserts) because they expect to find especially clear examples of evolutionary adaptation. One example is the study of water balance in desert-inhabiting mammals, which have been found to exhibit kidney specializations.

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
Giraffe
The giraffe is an African even-toed ungulate mammal, the tallest of all extant land-living animal species, and the largest ruminant...

 have been studied because of their long necks and the expectation that this would lead to specializaitons related to the regulation of blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...

. More generally, ectothermic vertebrates have been studied to determine how blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 acid-base balance and pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 change as body temperature changes.

Funding


In the United States, research in comparative physiology is funded by both the National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...

 and the National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

.

Societies


A number of scientific societies feature sections on comparative physiology, including:

Biographies


Knut Schmidt-Nielsen
Knut Schmidt-Nielsen
Knut Schmidt-Nielsen was a prominent figure in the field of comparative physiology and Professor of Physiology Emeritus at Duke University.-Background:...

 (1915–2007) was a major figure in vertebrate comparative physiology, serving on the faculty at Duke University
Duke University
Duke University is a private research university located in Durham, North Carolina, United States. Founded by Methodists and Quakers in the present day town of Trinity in 1838, the school moved to Durham in 1892. In 1924, tobacco industrialist James B...

 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
Grover C. Stephens
Grover Cleveland Stephens , born in Oak Park, Illinois, was a marine biologist and comparative physiologist at the University of Minnesota and the University of California at Irvine.- Early life, military service, and education :...

  (1925–2003) was a well-known invertebrate comparative physiologist, serving on the faculty of the University of Minnesota
University of Minnesota
The University of Minnesota, Twin Cities is a public research university located in Minneapolis and St. Paul, Minnesota, United States. It is the oldest and largest part of the University of Minnesota system and has the fourth-largest main campus student body in the United States, with 52,557...

 until becoming the founding chairman of the Department of Organismic Biology at the University of California at Irvine in 1964. He 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 as well.

Some journals that publish articles in comparative animal physiology


Further reading

  • Barrington, E. J. W. 1975. Comparative physiology and the challenge of design. Journal of Experimental Zoology 194:271-286.
  • Clark, A. J. 1927. Comparative physiology of the heart. Cambridge University Press, London.
  • Dantzler, W. H., ed. 1997. Handbook of physiology. Section 13: comparative physiology. Vol. I. Oxford Univ. Press, New York.
  • Dantzler, W. H., ed. 1997. Handbook of physiology. Section 13: comparative physiology. Vol. II. Oxford Univ. Press, New York. viii + 751-1824 pp.
  • Feder, M. E., A. F. Bennett, W. W. Burggren, and R. B. Huey, eds. 1987. New directions in ecological physiology. Cambridge Univ. Press, New York. 364 pp.
  • Garland, T., Jr.
    Theodore Garland, Jr.
    Theodore Garland, Jr. is a biologist specializing in evolutionary physiology. He was on the faculty at the University of Wisconsin–Madison for 14 years, served at the National Science Foundation for one year, and is currently Professor of Biology at the University of California, Riverside. He...

    , and P. A. Carter. 1994. Evolutionary physiology. Annual Review of Physiology 56:579-621. PDF
  • Gibbs, A. G. 1999. Laboratory selection for the comparative physiologist. Journal of Experimental Biology 202:2709-2718.
  • Gilmour, K. M., R. W. Wilson, and K. A. Sloman. 2005. The integration of behaviour into comparative physiology. Physiological and Biochemical Zoology 78:669-678.
  • Gordon, M. S., G. A. Bartholomew, A. D. Grinnell, C. B. Jorgensen, and F. N. White. 1982. Animal physiology: principles and adaptations. 4th ed. MacMillan, New York. 635 pages.
  • Greenberg, M. J., P. W. Hochachka, and C. P. Mangum, eds. 1975. New directions in comparative physiology and biochemistry. Journal of Experimental Zoology 194:1-347.
  • Hochachka, P. W., and G. N. Somero. 2002. Biochemical adaptation — mechanism and process in physiological evolution. Oxford University Press. 478 pp.
  • Mangum, C. P., and P. W. Hochachka. 1998. New directions in comparative physiology and biochemistry: mechanisms, adaptations, and evolution. Physiological Zoology 71:471-484.
  • Moyes, C. D., and P. M. Schulte. 2006. Principles of animal physiology. Pearson Benjamin Cummings, San Francisco. 734 pp.
  • Prosser, C. L., ed. 1950. Comparative animal physiology. W. B. Saunders Co., Philadelphia. ix + 888 pp.
  • Randall, D., W. Burggren, and K. French. 2002. Eckert animal physiology: mechanisms and adaptations. 5th ed. W. H. Freeman and Co., New York. 736 pp. + glossary, appendices, index.
  • Ross, D. M. 1981. Illusion and reality in comparative physiology. Canadian Journal of Zoology 59:2151-2158.
  • Schmidt-Nielsen, K. 1972. How animals work. Cambridge University Press, Cambridge.
  • Schmidt-Nielsen, K. 1984. Scaling: why is animal size so important? Cambridge University Press, Cambridge. 241 pp.
  • Schmidt-Nielsen, K. 1997. Animal physiology: adaptation and environment. 5th ed. Cambridge University Press, Cambridge. ix + 607 pp.
  • Schmidt-Nielsen, K. 1998. The camel's nose: memoirs of a curious scientist. 352 pp. The Island Press. Review
  • Somero, G. N. 2000. Unity in Diversity: A perspective on the methods, contributions, and future of comparative physiology. Annual Review of Physiology 62:927-937.
  • Stephens, G.C. and R.A. Schinske. 1961. Uptake of amino acids by marine invertebrates. Limnology and Oceanography 6(2):175-181.
  • Stephens, G.C. 1982. Recent progress in the study of "Die Ernährung der Wassertiere und der Stoffhaushalt der Gewasser". American Zoologist 22(3):611-619.
  • Manahan, D.T.
    Donal T. Manahan
    Donal Thomas Manahan is an Irish-born American marine scientist and comparative physiologist known for Antarctic and deep oceanic research on the physiology and ecology of marine invertebrates and their larvae in extreme environments....

    , S.H. Wright, G.C. Stephens
    Grover C. Stephens
    Grover Cleveland Stephens , born in Oak Park, Illinois, was a marine biologist and comparative physiologist at the University of Minnesota and the University of California at Irvine.- Early life, military service, and education :...

     and M.A. Rice
    Michael A. Rice
    Michael Alan Rice, is an American professor of fisheries and aquaculture at the University of Rhode Island and former state representative from South Kingstown, Rhode Island...

    . 1982. Transport of dissolved amino acids by the mussel, Mytilus edulis: Demonstration of net uptake from seawater by HPLC analysis. Science 215:1253-1255.
  • Swallow, J. G., and T. Garland, Jr.
    Theodore Garland, Jr.
    Theodore Garland, Jr. is a biologist specializing in evolutionary physiology. He was on the faculty at the University of Wisconsin–Madison for 14 years, served at the National Science Foundation for one year, and is currently Professor of Biology at the University of California, Riverside. He...

     2005. Selection experiments as a tool in evolutionary and comparative physiology: insights into complex traits - An introduction to the symposium. Integrative and Comparative Biology 45:387-390.
  • Willmer, P., G. Stone, and I. Johnston. 2005. Environmental physiology of animals. Second edition. Blackwell Science, Oxford, U.K. xiii + 754 pp.

See also

  • August Krogh
    August Krogh
    Schack August Steenberg Krogh FRS was a Danish professor of Romani background at the department of zoophysiology at the University of Copenhagen from 1916-1945...

  • Claude Bernard
    Claude Bernard
    Claude Bernard was a French physiologist. He was the first to define the term milieu intérieur . Historian of science I. Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science"...

  • Ecophysiology
    Ecophysiology
    Ecophysiology or environmental physiology is a biological discipline which studies the adaptation of organism's physiology to environmental conditions...

  • Evolutionary physiology
    Evolutionary physiology
    Evolutionary physiology is the study of physiological evolution, which is to say, the manner in which the functional characteristics of individuals in a population of organisms have responded to selection across multiple generations during the history of the population.It is a subdiscipline of both...

  • Human physiology
    Human physiology
    Human physiology is the science of the mechanical, physical, bioelectrical, and biochemical functions of humans in good health, their organs, and the cells of which they are composed. Physiology focuses principally at the level of organs and systems...

  • John Speakman
    John Speakman
    Professor John Speakman is a British biologist working at the University of Aberdeen, Institute of Biological and Environmental Sciences. He directs the University's Energetics Research Group, which is one of the world's leading groups using doubly labeled water to investigate energy expenditure...

  • Knut Schmidt-Nielsen
    Knut Schmidt-Nielsen
    Knut Schmidt-Nielsen was a prominent figure in the field of comparative physiology and Professor of Physiology Emeritus at Duke University.-Background:...

  • Krogh Principle
    Krogh Principle
    Krogh's principle states that "for such a large number of problems there will be some animal of choice, or a few such animals, on which it can be most conveniently studied." This concept is central to those disciplines of biology that rely on the comparative method, such as neuroethology,...

  • Lancelot Hogben
    Lancelot Hogben
    Lancelot Thomas Hogben FRS was a versatile British experimental zoologist and medical statistician. He is best known for developing Xenopus laevis as a model organism for biological research in his early career, attacking the eugenics movement in the middle of his career, and popularising books on...

  • Peter Hochachka
    Peter Hochachka
    Peter William Hochachka, OC, FRSC was a Canadian professor and zoologist.Born in Bordenave, Alberta, the son of the very Rev. William and Pearl Hochachka, he obtained his B.Sc. from the University of Alberta in 1959. He received his M.Sc. from Dalhousie University and a Ph.D...

  • Phylogenetic comparative methods
    Phylogenetic comparative methods
    Phylogenetic comparative methods use information on the evolutionary relationships of organisms to compare species...

  • Physiology
    Physiology
    Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

  • Raymond B. Huey
    Raymond B. Huey
    Raymond B. Huey is a biologist specializing in evolutionary physiology. He has taught at the University of Washington , and he earned his Ph.D. in biology at Harvard University under E. E. Williams. He is currently the chairman of the UW Biology Department.-Education:Huey earned his A.B...

  • Theodore Garland, Jr.
    Theodore Garland, Jr.
    Theodore Garland, Jr. is a biologist specializing in evolutionary physiology. He was on the faculty at the University of Wisconsin–Madison for 14 years, served at the National Science Foundation for one year, and is currently Professor of Biology at the University of California, Riverside. He...