Did lungs and the intracardiac shunt evolve to oxygenate the heart in vertebrates?

  title={Did lungs and the intracardiac shunt evolve to oxygenate the heart in vertebrates?},
  author={Colleen G Farmer},
  pages={358 - 372}
  • C. Farmer
  • Published 1 July 1997
  • Biology
  • Paleobiology
Traditional wisdom of the evolution of lungs in fishes is that lungs arose when gill ventilation was hindered by an aquatic habitat that was low in oxygen. This scenario has been buttressed primarily by a proposed correlation between extant air-breathing fishes and hypoxic habitats, as well as by the fact that early vertebrate fossils were found in sediments believed to indicate a semi-arid environment. There are problems with this scenario, yet it retains a dominant influence on how the… 

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Beyond the highly developed coronary circulations of endothermic sharks and tunas, cardiac evolution among fishes appears to have moved toward independence from a coronary circulation, beginning perhaps in the cyprinid lineage.

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The present findings show for the first time that in a wild living vertebrate species, specifically H. affinis, an extensive coronary artery system supplying the whole cardiac ventricle exists in the absence of a well‐developed compact ventricular myocardium, consistent with the notion derived from experimental work that myocardial cell proliferation and coronary vascular growth rely on distinct developmental programs.

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A detailed and re‐evaluated model of the evolution of air‐breathing among fishes that serves as a framework for addressing new questions on the cardiorespiratory changes associated with it is provided.

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  • S. Kurbel
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    Theoretical Biology and Medical Modelling
  • 2014
This review proposes that animal evolution was often driven by atmospheric oxygen availability, and it is proposed that Ural orogeny slowly elevated several highland habitats within the modern Ural region to heights above 2500 m, and animals in these habitats fully to adapted to hypoxia.

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Tribute to P. L. Lutz: a message from the heart – why hypoxic bradycardia in fishes?

  • A. Farrell
  • Biology
    Journal of Experimental Biology
  • 2007
The main thesis developed here is that hypoxic bradycardia could afford a number of direct benefits to the fish heart, largely because the oxygen supply to the spongy myocardium is precarious and because theFish heart has an unusual ability to produce large increases in cardiac stroke volume (VSH) that allow cardiac output to be maintained during hypoxia.

Pulmonary smooth muscle in vertebrates: A comparative review of the structure and function.

  • R. Cieri
  • Biology
    Integrative and comparative biology
  • 2019
Smooth muscle was likely involved in tension regulation ancestrally, and may serve to assist lung emptying in fishes and aquatic amphibians, as well as maintain internal lung structure in mammals and birds.



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Experimental analyses have established that in lower vertebrates lungs are ventilated with a buccal pulse pump, which is driven by identical sets of muscles acting in identical patterns in fishes and frogs, and that respiratory and locomotory patterns are coupled, further maximizing the efficiency of mammalian respiration.

The evolution of the terrestrial vertebrates: environmental and physiological considerations.

  • A. Bray
  • Environmental Science, Biology
    Philosophical transactions of the Royal Society of London. Series B, Biological sciences
  • 1985
A new model of tetrapod evolution is proposed in the light of the basic marine origin and character of the ancestors of the tetrapods.


  • C. Gans
  • Environmental Science
    Evolution; international journal of organic evolution
  • 1970
A review of the mechanisms of gas exchange, options available to the transitional forms, and the probability and sequence for the changes that actually occurred suggests that the classical observations on frogs do not by themselves furnish a suitable base for speculations about the behavior and physiology of the earliest amphibians.

Functional anatomy of the hearts of lungfishes and amphibians.

Representatives from all genera of lungfishes and several anurans and urodeles utilizing pulmonary breathing, show a preferential distribution of blood tending to minimize recirculation to the systemic and pulmonary circuits.


  • G. C. Packard
  • Environmental Science
    Evolution; international journal of organic evolution
  • 1974
The theory for a freshwater origin of air-breathing (and lungs) in Paleozoic vertebrates has won wide acceptance and the pervasiveness of the theory is revealed by the fact that certain groups of vertebrates are regarded as having originated in freshwaters, despite the existence of paleontologic evidence to the contrary.


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The extent to which luminal venous blood obviates the need for a coronary circulation and the extent toWhich the coronary circulation supplements the luminal oxygen supply are discussed.

The Evolution of Lung-Gill Bimodal Breathing and the Homology of Vertebrate Respiratory Pumps

A comparative analysis of actinopterygian and sarcoperygian aerial buccal pumps indicates that the primitive pattern of air transfer differs fundamentally between these two clades, suggesting that the independent evolution from different aquatic buCCal pumps may be due to their independent evolution to a single aerialbuccal pump.

9 Air Breathing in Fishes

Acidosis and cardiac muscle contractility: comparative aspects.

  • H. GesserO. Poupa
  • Biology
    Comparative biochemistry and physiology. A, Comparative physiology
  • 1983