Richard E. Pattle contributed enormously to the biology of the pulmonary su
rfactant system. However, Pattle can also be regarded as the founding fathe
r of comparative and evolutionary research of the surfactant system. He con
tributed eight seminal papers of the 167 publications we have located on th
is topic, In particular, Pattle produced a synthesis interpreting the evolu
tion of the surfactant system that formed the foundation for the area. Prep
ared 25 years ago this synthesis spawned the three great discoveries in the
comparative biology of the surfactant system: (1) that the surfactant syst
em has been highly conserved throughout the enormous radiation of the air b
reathing vertebrates; (2) that temperature is the major selective condition
that influences surfactant composition; (3) that acting as an anti-adhesiv
e is one primitive and ubiquitous function of vertebrate surfactant. Here w
e review the literature and history of the comparative and evolutionary bio
logy of the surfactant system and highlight the areas of comparative physio
logy that will contribute to our understanding of the surfactant system in
the future. In our view the surfactant system is a neatly packaged system,
located in a single cell and highly conserved, yet spectacularly complex. T
he surfactant system is one of the best systems we know to examine evolutio
nary processes in physiology as well as gain important insights into gas tr
ansfer by complex organisms. (C) 2001 Elsevier Science Inc. All rights rese
rved.