The evolution of adaptations for life on land have long
puzzled biologists – are feathers descendents of dinosaur scales, how did arms
and legs evolve from fins, and from what ancient fish organ did the lung
evolve?
Biologists have known that the co-development of the
cardiovascular and pulmonary systems is a recent evolutionary adaption to life
outside of water, coupling the function of the heart with the gas exchange
function of the lung. And, the lung is one of the most recent organs to have
evolved in mammals and is arguably the most vital for terrestrial life.