Lungs are what enabled the ancestors of all tetrapods to climb out of the Devonian soup some 400 million years ago … Since they utilize the vast surface area of alveoli for gas exchange, rather than the relatively limited amount of surface area provided by a creature’s skin …
- An average human adult’s skin has a surface area of roughly 16-21 square feet
- whereas the surface area of the alveoli inside that same human is about 100 square yards!
Amphibians are neither large, nor particularly active, … amphibians of the order Anura (ie: frogs) evolved four mechanisms for breathing:
- through gills
- via lungs
- through their very permeable skin
- through sensitive skin inside the mouth.
Lungless salamanders (2/3 of all salamander diversity) took things one step further and got rid of the primitive lungs all together, to rely solely on cutaneous gas exchange.
Read more at Salameandering Into Cutaneous Respiration.
An illustration I did for Instinct Magazine on unfair Adoption cases.
This should have thousands of notes.
84,908 and counting.
I reblog this every time it comes up on my dash. Such a powerful message.