Reptiles:
* Lungs: Relatively simple, with a limited surface area for gas exchange.
* Breathing: Use a costal ventilation system, relying primarily on ribcage movements to draw air in and out.
* Diaphragm: Absent.
Mammals:
* Lungs: Highly complex and efficient, with extensive alveoli (tiny air sacs) providing a vast surface area for gas exchange.
* Breathing: Use a diaphragmatic ventilation system, relying heavily on the muscular diaphragm to draw air into the lungs.
* Diaphragm: Present and plays a crucial role in breathing.
Functional Differences:
* Increased efficiency: Mammalian lungs, with their large surface area and diaphragm-driven breathing, are much more efficient at oxygen uptake and carbon dioxide removal. This allows mammals to maintain high metabolic rates and sustain higher activity levels.
* Thermoregulation: Efficient respiration is also important for maintaining a stable body temperature, a key feature of mammalian endothermy.
* Adaptation to diverse environments: Mammalian respiratory systems have evolved to function effectively in a wide range of environments, including high altitudes, underwater, and underground.
Evolutionary Significance:
The development of a diaphragm and more complex lungs in mammals represents a major evolutionary adaptation that allowed them to occupy a wide range of ecological niches and become the dominant terrestrial vertebrates. This is a prime example of how anatomical features can evolve to support specific functions and lead to significant evolutionary changes.
