Bergmann's rule

Bergmann's rule - Penguins on the Earth (mass m, height h)[1]

Bergmann's rule is an ecogeographical rule that states that, within a broadly distributed taxonomic clade, populations and species of larger size are found in colder environments, while populations and species of smaller size are found in warmer regions. The rule derives from the relationship between size in linear dimensions meaning that both height and volume will increase in colder environments. Bergmann's rule only describes the overall size of the animals, but does not include body proportions like Allen's rule does.

Although originally formulated in relation to species within a genus, it has often been recast in relation to populations within a species. It is also often cast in relation to latitude. It is possible that the rule also applies to some plants, such as Rapicactus.

The rule is named after nineteenth century German biologist Carl Bergmann, who described the pattern in 1847, although he was not the first to notice it. Bergmann's rule is most often applied to mammals and birds which are endotherms, but some researchers have also found evidence for the rule in studies of ectothermic species,[2][3] such as the ant Leptothorax acervorum. While Bergmann's rule appears to hold true for many mammals and birds, there are exceptions.[4][5][6]

Larger-bodied animals tend to conform more closely to Bergmann's rule than smaller-bodied animals, at least up to certain latitudes. This perhaps reflects a reduced ability to avoid stressful environments, such as by burrowing.[7] In addition to being a general pattern across space, Bergmann's rule has been reported in populations over historical and evolutionary time when exposed to varying thermal regimes.[8][9][10] In particular, temporary, reversible dwarfing of mammals has been noted during two relatively brief upward excursions in temperature during the Paleogene: the Paleocene-Eocene thermal maximum[11] and the Eocene Thermal Maximum 2.[12]

  1. ^ FRYDRÝŠEK, Karel (2019). Biomechanika 1. Ostrava, Czech Republic: VSB – Technical University of Ostrava, Faculty of Mechanical Engineering, Department of Applied Mechanics. pp. 337–338. ISBN 978-80-248-4263-9.
  2. ^ Olalla-Tárraga, Miguel Á.; Rodríguez, Miguel Á.; Hawkins, Bradford A. (2006). "Broad-scale patterns of body size in squamate reptiles of Europe and North America". Journal of Biogeography. 33 (5): 781–793. Bibcode:2006JBiog..33..781O. doi:10.1111/j.1365-2699.2006.01435.x. S2CID 59440368.
  3. ^ Timofeev, S. F. (2001). "Bergmann's Principle and Deep-Water Gigantism in Marine Crustaceans". Biology Bulletin of the Russian Academy of Sciences. 28 (6): 646–650. doi:10.1023/A:1012336823275. S2CID 28016098.
  4. ^ Meiri, S.; Dayan, T. (2003-03-20). "On the validity of Bergmann's rule". Journal of Biogeography. 30 (3): 331–351. Bibcode:2003JBiog..30..331M. doi:10.1046/j.1365-2699.2003.00837.x. S2CID 11954818.
  5. ^ Ashton, Kyle G.; Tracy, Mark C.; Queiroz, Alan de (October 2000). "Is Bergmann's Rule Valid for Mammals?". The American Naturalist. 156 (4): 390–415. doi:10.1086/303400. JSTOR 10.1086/303400. PMID 29592141. S2CID 205983729.
  6. ^ Millien, Virginie; Lyons, S. Kathleen; Olson, Link; et al. (May 23, 2006). "Ecotypic variation in the context of global climate change: Revisiting the rules". Ecology Letters. 9 (7): 853–869. Bibcode:2006EcolL...9..853M. doi:10.1111/j.1461-0248.2006.00928.x. PMID 16796576.
  7. ^ Freckleton, Robert P.; Harvey, Paul H.; Pagel, Mark (2003). "Bergmann's rule and body size in mammals". The American Naturalist. 161 (5): 821–825. doi:10.1086/374346. JSTOR 10.1086/374346. PMID 12858287. S2CID 44612517.
  8. ^ Smith, Felia A.; Betancourt, Julio L.; Brown, James H. (December 22, 1995). "Evolution of Body Size in the Woodrat over the Past 25,000 Years of Climate Change". Science. 270 (5244): 2012–2014. Bibcode:1995Sci...270.2012S. doi:10.1126/science.270.5244.2012. S2CID 129915445.
  9. ^ Huey, Raymond B.; Gilchrist, George W.; Carlson, Margen L.; Berrigan, David; Serra, Luıs (January 14, 2000). "Rapid Evolution of a Geographic Cline in Size in an Introduced Fly". Science. 287 (5451): 308–309. Bibcode:2000Sci...287..308H. doi:10.1126/science.287.5451.308. PMID 10634786. S2CID 23209206.
  10. ^ Hunt, Gene; Roy, Kaustuv (January 31, 2006). "Climate change, body size evolution, and Cope's rule in deep-sea ostracodes". Proceedings of the National Academy of Sciences of the United States of America. 103 (5): 1347–1352. Bibcode:2006PNAS..103.1347H. doi:10.1073/pnas.0510550103. PMC 1360587. PMID 16432187.
  11. ^ Secord, R.; Bloch, J.I.; Chester, S.G.B.; Boyer, D.M.; Wood, A.R.; Wing, S.L.; Kraus, M.J.; McInerney, F.A.; Krigbaum, J. (2012). "Evolution of the Earliest Horses Driven by Climate Change in the Paleocene-Eocene Thermal Maximum". Science. 335 (6071): 959–962. Bibcode:2012Sci...335..959S. doi:10.1126/science.1213859. PMID 22363006. S2CID 4603597. Archived from the original on 2019-04-09. Retrieved 2020-01-08.
  12. ^ Erickson, Jim (November 1, 2013). "Global warming led to dwarfism in mammals — twice". University of Michigan. Retrieved 2013-11-12.