Comparative physiology

Last updated

Comparative physiology is a subdiscipline of physiology that studies and exploits the diversity of functional characteristics of various kinds of organisms. It is closely related to evolutionary physiology and environmental physiology. Many universities offer undergraduate courses that cover comparative aspects of animal physiology. According to Clifford Ladd Prosser, "Comparative Physiology is not so much a defined discipline as a viewpoint, a philosophy." [1]

Contents

History

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.[ citation needed ]

Methodology

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 Carter [4] ):

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. [5]

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 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 cues,
  • it can't be measured on museum 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, 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), [6] 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." [7]
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." [1]

Comparative physiologists often study organisms that live in "extreme" environments (e.g., deserts) because they expect to find especially clear examples of evolutionary adaptation. [4] One example is the study of water balance in desert-inhabiting mammals, which have been found to exhibit kidney specializations. [8]

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.

Funding

In the United States, research in comparative physiology is funded by both the National Institutes of Health and the National Science Foundation.[ citation needed ]

Societies

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

Biographies

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.[ citation needed ]

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.

Some journals that publish articles in comparative animal physiology

See also

Related Research Articles

<span class="mw-page-title-main">Physiology</span> Science regarding function of organisms or living systems

Physiology is the scientific study of functions and mechanisms in a living system. As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and physical functions in a living system. According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology.

Zoology is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one of the primary branches of biology. The term is derived from Ancient Greek ζῷον, zōion ('animal'), and λόγος, logos.

<span class="mw-page-title-main">August Krogh</span> Danish professor and Nobel laureate

Schack August Steenberg Krogh was a Danish professor at the department of zoophysiology at the University of Copenhagen from 1916 to 1945. He contributed a number of fundamental discoveries within several fields of physiology, and is famous for developing the Krogh Principle.

Experimental evolution is the use of laboratory experiments or controlled field manipulations to explore evolutionary dynamics. Evolution may be observed in the laboratory as individuals/populations adapt to new environmental conditions by natural selection.

<span class="mw-page-title-main">Allometry</span> Study of the relationship of body size to shape, anatomy, physiology, and behavior

Allometry is the study of the relationship of body size to shape, anatomy, physiology and behaviour, first outlined by Otto Snell in 1892, by D'Arcy Thompson in 1917 in On Growth and Form and by Julian Huxley in 1932.

Peter William Hochachka, was a Canadian professor and zoologist at the University of British Columbia (UBC). He is known for his foundational work in creating the new field of adaptational biochemistry, connecting metabolic biochemistry with comparative physiology.

<span class="mw-page-title-main">Biologist</span> A scientist studying living organisms

A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually specialize in a particular branch of biology and have a specific research focus.

<span class="mw-page-title-main">Phenotypic plasticity</span> Trait change of an organism in response to environmental variation

Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompasses all types of environmentally induced changes that may or may not be permanent throughout an individual's lifespan.

Raymond Brunson Huey is a biologist specializing in evolutionary physiology. He has taught at the University of Washington (UW), and he earned his Ph.D. in biology at Harvard University under E. E. Williams. He has recently been the chair of the university's biology department, but a retirement celebration was held on 4 Oct. 2013 in Seattle.

Gerald Allan Kerkut was a British zoologist and physiologist.

Biological constraints are factors which make populations resistant to evolutionary change. One proposed definition of constraint is "A property of a trait that, although possibly adaptive in the environment in which it originally evolved, acts to place limits on the production of new phenotypic variants." Constraint has played an important role in the development of such ideas as homology and body plans.

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, comparative physiology, and more recently functional genomics.

<span class="mw-page-title-main">Knut Schmidt-Nielsen</span>

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

<span class="mw-page-title-main">Evolutionary physiology</span> Study of evolutionary changes in physiological characteristics

Evolutionary physiology is the study of the biological evolution of physiological structures and processes; that is, the manner in which the functional characteristics of organisms have responded to natural selection or sexual selection or changed by random genetic drift across multiple generations during the history of a population or species. It is a sub-discipline of both physiology and evolutionary biology. Practitioners in the field come from a variety of backgrounds, including physiology, evolutionary biology, ecology, and genetics.

Phylogenetic comparative methods (PCMs) use information on the historical relationships of lineages (phylogenies) to test evolutionary hypotheses. The comparative method has a long history in evolutionary biology; indeed, Charles Darwin used differences and similarities between species as a major source of evidence in The Origin of Species. However, the fact that closely related lineages share many traits and trait combinations as a result of the process of descent with modification means that lineages are not independent. This realization inspired the development of explicitly phylogenetic comparative methods. Initially, these methods were primarily developed to control for phylogenetic history when testing for adaptation; however, in recent years the use of the term has broadened to include any use of phylogenies in statistical tests. Although most studies that employ PCMs focus on extant organisms, many methods can also be applied to extinct taxa and can incorporate information from the fossil record.

Ecological and Evolutionary Physiology is a peer-reviewed scientific journal published by the University of Chicago Press on behalf of the Society for Integrative and Comparative Biology. The journal publishes original research examining fundamental questions about how the ecological environment and/or evolutionary history interact with physiological function, as well as the ways physiology may constrain behavior. For EEP, physiology denotes the study of function in the broadest sense, across levels of organization from molecules to morphology to organismal performance and on behavior and life history traits.

Theodore Garland Jr. is a biologist specializing in evolutionary physiology at the University of California, Riverside.

<span class="mw-page-title-main">Ionocyte</span>

An ionocyte (formerly called a chloride cell) is a mitochondrion-rich cell within ionoregulatory organs of animals, such as teleost fish gill, insect Malpighian tubules, crustacean gills, antennal glands and maxillary glands, and copepod Crusalis organs. These cells contribute to the maintenance of optimal osmotic, ionic, and acid-base levels within metazoans. In aquatic invertebrates, ionocytes perform the functions of both ion uptake and ion excretion. In marine teleost fish, by expending energy to power the enzyme Na+/K+-ATPase and in coordination with other protein transporters, ionocytes pump excessive sodium and chloride ions against the concentration gradient into the ocean. Conversely, freshwater teleost ionocytes use this low intracellular environment to attain sodium and chloride ions into the organism, and also against the concentration gradient. In larval fishes with underdeveloped / developing gills, ionocytes can be found on the skin and fins.

The following outline is provided as an overview of and topical guide to physiology:

Albert Farrell Bennett is an American zoologist, physiologist, evolutionary biologist, author, and academic. He is Dean Emeritus of the School of Biological Sciences at University of California, Irvine.

References

  1. 1 2 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.
  2. ↑ 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.
  3. ↑ 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.
  4. 1 2 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.
  5. ↑ 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.
  6. ↑ 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.
  7. ↑ Prosser (1950, p. 1)
  8. ↑ 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.

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.