| 词条 | Carrier's constraint |
| 释义 |
It was named, by English paleontologist Richard Cowen, for David R. Carrier, who wrote his observations on the problem in 1987.[2][3][4] ConsequencesMost lizards move in short bursts, with long pauses for breath. Around the Late Triassic period, animals with Carrier's constraint were preyed on by bipedal species that evolved a more efficient stride. SolutionsWorkaroundsMost snakes have only one lung, so Carrier's constraint does not apply. Monitor lizards increase their stamina by using bones and muscles in the throat and floor of the mouth to "gulp" air via gular pumping.[5]Some other lizards, mainly agamids, use bipedal locomotion for running and avoid sideway flexing. Bipedality in modern lizards is very rare, but it is effective way to run without pause and breath, for catching active prey or evading predators. Crocodilians use a "high walk", with a more erect limb posture that minimizes sideways flexing, to cross long distances. However, as they evolved from upright walkers with limited bipedality, this may simply be a remnant of past behavior rather than a specific adaptation to overcome this difficulty. Todd J. Uriona (University of Utah) hypothesizes that costal ventilation may have aided the upright posture in overcoming the constraint.[6]Avoiding the constraintBirds have erect limbs and rigid bodies, and therefore do not flex sideways when moving. In addition many of them have a mechanism which pumps both lungs simultaneously when the birds rock their hips.{{cn|date=July 2017}} Most mammals have erect limbs and flexible bodies, which makes their bodies flex vertically when moving quickly. This aids breathing, as it expands and compresses both lungs simultaneously.{{cn|date=July 2017}} Contrary evidenceContrary to the above model, breathing is maintained in lizards during movement, even above their aerobic scope, and arterial blood remains well oxygenated.[7] In popular culturePaleontologist Richard Cowen wrote a limerick to explain and celebrate Carrier's rule: The reptilian idea of fun Is to bask all day in the sun. A physiological barrier, Discovered by Carrier, Says they can't breathe, if they run.[3] See also
References1. ^{{cite journal | last=Carrier | first=D.R. | title=The evolution of locomotor stamina in tetrapods: circumventing a mechanical constraint | journal=Paleobiology | volume = | issue=13 | pages=326–341 | year=1987}} 2. ^{{cite book |last= Cowen|first= Richard |chapter= Locomotion and Respiration in Aquatic Air-Breathing Vertebrates |title= Evolutionary Paleobiology |editor= Jablonski, David |location= Chicago |publisher= University of Chicago Press |year= 1996 |page= 337+ |ISBN= 0-226-38911-1|display-editors=etal}} 3. ^1 {{cite web |url= http://mygeologypage.ucdavis.edu/cowen/~GEL107/carrierconstraint.html |author= Cowen, Richard |date= 2003 |title= Respiration, Metabolism, and Locomotion |publisher= Richard Cowen, University of California, Davis |quote= If the animal is walking, it may be able to breathe between steps, but sprawling vertebrates cannot run and breathe at the same time. I shall call this problem Carrier's Constraint. |accessdate= October 21, 2014}} 4. ^{{cite journal |url= http://www.americanscientist.org/issues/postComment.aspx?id=3663&y=2008&no=1&page=4 |last= Shipman |first= Pat |title= Freed to Fly Again |journal= American Scientist |location= Research Triangle Park |publisher= Sigma Xi |volume= 96 |issue= 1 |date= January 2008 |page= 20 |quote= Carrier's constraint is named for David R. Carrier at the University of Utah in Salt Lake City, who observed that the typical sprawling gait of a lizard restricts the animal's ability to breathe while running or walking. |accessdate= October 21, 2014}} 5. ^{{cite journal |url= https://www.questia.com/read/1P3-635880221 |last= Summers |first= Adam |title= Monitor Marathons |journal= Natural History |volume= 112 |issue= 5 |date= 2003 |page= 32 |accessdate= October 21, 2014}} 6. ^{{cite web |url= https://books.google.com/books?id=_WYGA8NXmbIC&pg=PA38 |author= Uriona, Todd J. |date= 2008 |title= The Function of the Crocodilean Diaphragmaticus |publisher= ProQuest |accessdate= October 21, 2014}} 7. ^{{cite encyclopedia | last=Bennett | first=Albert F. | url=http://compphys.bio.uci.edu/bennett/pubs/120.pdf | title=Exercise performance of reptiles | pages=113–138 | encyclopedia=Comparative Vertebrate Exercise Physiology: Phyletic Adaptations | series=Advances in Veterinary Science and Comparative Medicine | volume=38B | editor1-last=Jones | editor1-first=James H. | editor2-last=Cornelius | editor2-first=Charles E. | editor3-last=Marshak | editor3-first=R. R. | publisher=Academic Press | location=New York | year=1994 | isbn=0120392399}} 1 : Respiration |
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