Relationships between specialized cells, capillaries and intermediary cytofibrillary elements. XIIth note. Biological evolution of the respiratory stereotype and subsystem in invertebrates.

This note presents the respiratory stereotype and subsystem in invertebrates, developing the previous notes on the emunctory stereotype and subsystem (Xth and XIth notes). As in the previous ones, Cannon's homeostasis conception and Bertlanffy's theory of systems were corroborated with Needham's theory of internal laws and of limits of organizational biological levels, and with the author's theory of biological stereotypes (Mârza, Repciuc, Eskenasy, 1962). Four links of the respiratory stereotype (Rsp. Stp.) and subsystem (Rsp. SS) were distinguished. The respiratory subsystem was differentiated when, in triblastic animals, the organizational level of higher worms and of their offsprings was reached. The four links of the Rsp. Stp. are: the Ist link is represented by the oxidoreduction processes of tissue and organ cells; the IInd is the internal conveying link of O2 and CO2; the IIIrd comprises the osmotic surfaces changes and the transport of gases inwards the branchiae or lungs, and later by the water (respectively air)--blood barrier; the IVth link is formed from the structures and mechanisms of rhythmic movements which significantly increase the exchanges at the barrier level. Each link has its specific properties. The gradual evolution of each link and of the vicarious organs of gas exchange is dwelt upon, as well as the interactions between the respiratory subsystem and the other homeostasis subsystems. The theoretical interpretation of the Rsp. Stp. and Rsp. SS evolution also resorted to the theories of stabilizing selection (Schmalhausen, 1949), of canalizing selection (Waddington, 1975 and of disruptive selection (Simpson, 1953; Mayr, 1970).