Yes, you did in fact read that title correctly. There is a fish with a lung! The fish is called coelacanth. It’s related to the first fish that crawled onto land 410 million years. It was long thought to be extinct but this is due to it living in the deep sea. New research involving x ray scans of the fish through its various life stages have found the exsistence of a lung like organ.
The research coming from the university of Rio de Janeiro found that the embryos had a fully functional lung. As the fish matures the organ becomes almost useless and is only used for bouyancy. This has the potential to mean because of the fish being a deep sea dweller that it used the lung to breathe.
The Difference between Gills and Lungs
The main difference between gills and lungs are that gills can extract dissolved oxygen water and lungs extract atmospheric oxygen. Gills work with a counter current system. This works by flowing blood around the gills and water around the gills in opposite directions (see diagram). The lamellae of the gills increase the surface area. Lungs work by getting atmospheric oxygen and diffusing that into capillaries. Then carbon dioxide diffuses back out and leaves the lungs. This all works with the help of intercostal muscles and differences in pressure. Gills can also remove excretory products however lungs cannot.
Although the lung in the coelacanth does not work the news of this mystifying fish just shows how little we know about the deep ocean. I look forward to hearing more about the wonderful world of the deep sea in the near future.
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