Which Of The Following Animals Has The Largest Brain-to-body Size Ratio

Measurement used for rough guess of the intelligence of an animal

Encephalon-to-body mass ratio, also known as the brain-to-torso weight ratio, is the ratio of brain mass to body mass, which is hypothesized to exist a rough estimate of the intelligence of an animate being, although fairly inaccurate in many cases. A more complex measurement, encephalization quotient, takes into business relationship allometric furnishings of widely divergent body sizes across several taxa.^{[1] [2]} The raw brain-to-body mass ratio is nevertheless simpler to come by, and is still a useful tool for comparing encephalization inside species or between fairly closely related species.

Brain-trunk size relationship [edit]

Brain size unremarkably increases with body size in animals (i.e. large animals usually have larger brains than smaller animals);^[4] the relationship is non, however, linear. Small mammals such as mice may have a encephalon/body ratio similar to humans, while elephants accept a comparatively lower brain/body ratio.^{[iv] [5]}

In animals, it is thought that the larger the brain, the more brain weight will be bachelor for more circuitous cerebral tasks. However, big animals need more neurons to represent their own bodies and control specific muscles;^{[ clarification needed ] [ citation needed ]} thus, relative rather than absolute brain size makes for a ranking of animals that better coincides with the observed complexity of animate being behaviour. The human relationship betwixt brain-to-trunk mass ratio and complexity of behaviour is non perfect as other factors also influence intelligence, similar the evolution of the recent cognitive cortex and unlike degrees of brain folding,^[6] which increment the surface of the cortex, which is positively correlated in humans to intelligence. The noted exception to this, of class, is swelling of the brain which, while resulting in greater area, does not alter the intelligence of those suffering from it.^[7]

Relation to metabolism [edit]

The relationship between encephalon weight and body weight of all living vertebrates follows two completely separate linear functions for cold-blooded and warm-blooded animals.^[viii] Common cold-blooded vertebrates have much smaller brains than warm-blooded vertebrates of the same size. However, if brain metabolism is taken into business relationship, the brain-to-body relationship of both warm and cold-blooded vertebrates becomes like, with nearly using betwixt 2 and 8 per centum of their basal metabolism for the brain and spinal cord.^[9]

Comparisons between groups [edit]

Species	Brain:body mass ratio (E:South)[iv]
small ants	one:7[10]
minor birds	1:12
mouse	1:forty
human	1:40
true cat	1:100
canis familiaris	ane:125
frog	1:172
lion	1:550
elephant	ane:560
horse	1:600
shark	i:2496
hippopotamus	i:2789

Dolphins take the highest brain-to-torso weight ratio of all cetaceans.^[11] Monitor lizards, tegus and anoles and some tortoise species accept the largest amidst reptiles. Among birds, the highest brain-to-trunk ratios are plant among parrots, crows, magpies, jays and ravens. Among amphibians, the studies are still limited. Either octopuses^[12] or jumping spiders^[13] have some of the highest for an invertebrate, although some pismire species have 14%-15% of their mass in their brains, the highest value known for any animal. Sharks have one of the highest for fish alongside manta rays (although the electrogenic elephantfish has a ratio near 80 times higher - about 1/32, which is slightly higher than that for humans).^[14] Treeshrews have a college encephalon to trunk mass ratio than any other mammal, including humans.^[15] Shrews^{[ description needed ]} hold well-nigh 10% of their body mass in their brain.^{[ commendation needed ]}

It is a trend that the larger the animal gets, the smaller the brain-to-trunk mass ratio is. Large whales have very small brains compared to their weight, and small rodents like mice have a relatively large brain, giving a encephalon-to-torso mass ratio similar to humans.^[4] One explanation could exist that equally an animal'due south brain gets larger, the size of the neural cells remains the same, and more than nervus cells will crusade the brain to increment in size to a bottom degree than the remainder of the torso. This phenomenon tin be described by an equation of the form E = CS^r , where Due east and S are brain and body weights, r a constant that depends on fauna family (simply close to 2/3 in many vertebrates^[16]), and C is the cephalization factor.^[12] It has been argued that the animal's ecological niche, rather than its evolutionary family, is the principal determinant of its encephalization gene C.^[16] In the essay "Bligh'south Compensation",^[17] Stephen Jay Gould noted that if one looks at vertebrates with very low encephalization quotient, their brains are slightly less massive than their spinal cords. Theoretically, intelligence might correlate with the absolute amount of brain an animal has after subtracting the weight of the spinal string from the brain. This formula is useless for invertebrates because they do not have spinal cords, or in some cases, central nervous systems.

Criticism [edit]

Recent enquiry indicates that, in non-human being primates, whole brain size is a meliorate mensurate of cognitive abilities than encephalon-to-torso mass ratio. The total weight of the species is greater than the predicted sample only if the frontal lobe is adapted for spatial relation.^[18] The encephalon-to-torso mass ratio was yet found to be an excellent predictor of variation in problem solving abilities among carnivoran mammals.^[19]

In humans, the encephalon to body weight ratio can vary greatly from person to person; it would exist much higher in an underweight person than an overweight person, and higher in infants than adults. The same trouble is encountered when dealing with marine mammals, which may have considerable body fat masses. Some researchers therefore prefer lean body weight to brain mass as a amend predictor.^[twenty]

Come across also [edit]

• Cranial capacity
• Encephalization
• Listing of animals past number of neurons
• Schauenberg's index

References [edit]

1. ^ "Evolution of Intelligence". Ircamera.as.arizona.edu. Retrieved 2011-05-12 .
2. ^ Cairό, O (2011). "External measures of cognition". Front end Hum Neurosci. 5: 108. doi:10.3389/fnhum.2011.00108. PMC3207484. PMID 22065955.
3. ^ Fine, M. L.; Horn, G. H.; Cox, B. (1987-03-23). "Acanthonus armatus, a Deep-Ocean Teleost Fish with a Minute Brain and Big Ears". Proceedings of the Royal Society of London B: Biological Sciences. 230 (1259): 257–265. Bibcode:1987RSPSB.230..257F. doi:ten.1098/rspb.1987.0018. ISSN 0962-8452. PMID 2884671.
4. ^ ^{a b c d} "Brain and Trunk Size... and Intelligence". SerendipStudio.org. 2003-03-07. Retrieved 2019-02-24 .
5. ^ Hart, B. L.; Hart, Fifty. A.; McCoy, M.; Sarath, C. R. (November 2001). "Cerebral behaviour in Asian elephants: use and modification of branches for wing switching". Animal Behaviour. 62 (5): 839–847. doi:10.1006/anbe.2001.1815. S2CID 53184282.
6. ^ "Cortical Folding and Intelligence". Retrieved 2008-09-15 .
7. ^ Haier, R.J.; Jung, R.E.; Yeo, R.C.; Caput, K.; Alkired, Grand.T. (2004). "Structural encephalon variation and general intelligence". NeuroImage. 23 (one): 425–433. doi:10.1016/j.neuroimage.2004.04.025. PMID 15325390. S2CID 29426973.
8. ^ A graph of the relation between brain weight and body weight of living vertebrates Retrieved 10 February 2018.
9. ^ A graph of the relation of CNS to body metabolism in vertebrates Retrieved 10 Feb 2018.
10. ^ Seid, M. A.; Castillo, A.; Wcislo, W. T. (2011). "The Allometry of Encephalon Miniaturization in Ants". Brain, Behavior and Evolution. 77 (i): five–13. doi:10.1159/000322530. PMID 21252471. S2CID 6177033.
11. ^ Marino, L.; Sol, D.; Toren, Thou. & Lefebvre, L. (2006). "Does diving limit encephalon size in cetaceans?" (PDF). Marine Mammal Science. 22 (2): 413–425. doi:10.1111/j.1748-7692.2006.00042.x.
12. ^ ^{a b} Gould (1977) Ever since Darwin, c7s1
13. ^ "Jumping Spider Vision". Retrieved 2009-10-28 .
14. ^ Nilsson, Göran Eastward. (1996). "Brain And Trunk Oxygen Requirements Of Gnathonemus Petersii, A Fish With An Exceptionally Large Brain" (PDF). The Journal of Experimental Biology. 199 (3): 603–607. doi:x.1242/jeb.199.3.603. PMID 9318319.
15. ^ http://genome.wustl.edu/genomes/view/tupaia_belangeri is an article on Tupaia belangeri from The Genome Plant published by Washington Academy, archived at https://web.archive.org/web/20100601201841/https://www.genome.wustl.edu/genomes/view/tupaia_belangeri
16. ^ ^{a b} Pagel M. D., Harvey P. H. (1989). "Taxonomic differences in the scaling of encephalon on body weight amid mammals". Scientific discipline. 244 (4912): 1589–93. Bibcode:1989Sci...244.1589P. doi:ten.1126/science.2740904. PMID 2740904.
17. ^ "Bligh'due south Compensation". Archived from the original on 2001-07-09. Retrieved 2011-05-12 .
18. ^ Deaner, Robert O.; Isler, Karin; Burkart, Judith; Van Schaik, Carel (2007). "Overall Brain Size, and Not Encephalization Caliber, Best Predicts Cognitive Power beyond Not-Human being Primates". Brain Behav Evol. seventy (2): 115–124. CiteSeerX10.1.ane.570.7146. doi:10.1159/000102973. PMID 17510549. S2CID 17107712.
19. ^ Benson-Amram, S.; Dantzer, B.; Stricker, Yard.; Swanson, E.M.; Holekamp, One thousand.E. (25 January 2016). "Encephalon size predicts trouble-solving ability in mammalian carnivores" (PDF). Proceedings of the National University of Sciences. 113 (9): 2532–2537. Bibcode:2016PNAS..113.2532B. doi:ten.1073/pnas.1505913113. PMC4780594. PMID 26811470. Retrieved 29 January 2016.
20. ^ Schoenemann, P. Thomas (2004). "Brain size scaling and body composition in mammals". Brain, Beliefs and Evolution. 63 (1): 47–60. doi:10.1159/000073759. ISSN 0006-8977. PMID 14673198. S2CID 5885808.

External links [edit]

• https://web.archive.org/web/20050325105538/http://www.wsu.edu/~taflinge/mindwork/mawint1.html
• A graph of body mass vs. encephalon mass
• "Bligh'south Bounty" — Stephen Jay Gould
• Suzana Herculano Houzel: What is so special about the human being brain TED talk, June 2013.

Source: https://en.wikipedia.org/wiki/Brain-to-body_mass_ratio

Posted by: gallaghermathe1984.blogspot.com

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