When Fish First Breathed Air, by PBS Eons

[Rumraket (Mikkel R.)]

@John_Harshman

Swim bladders would seem to be an actinopterygian invention, and there is a placoderm fossil showing preserved lungs.

This is apparently also confirmed by two new studies in comparative genomics, illuminating the fish-to-tetrapod transition:

Per Ahlberg writes about two new papers on the fish-to-tetrapod transition

Very interesting summary of the results. Pdf can be accessed here: A comparative genomic framework for the fish-tetrapod transition Ahlberg PE. A comparative genomic framework for the fish-tetrapod transition. Sci China Life Sci. 2021 Apr;64(4):664-666. doi: 10.1007/s11427-021-1903-x. Epub 2021 Mar 1. PMID: 33660224. Some highlights: The evolution of tetrapods (land vertebrates) from lobe-finned fishes, nearly 400 million years ago, was a hugely important event. For one thing, if these ancient fishes had not found a way to adapt to life out of the water, we humans would not exist. To investigate this event we can look at the fossil record, but that only tells us about changes in the skeleton. The equally important changes that must have occurred in the soft anatomy and physiology would appear to be lost, undocumented, in the mists of time. Or are they? In two linked papers published this week in Cell, Wang et al. (2021) and Bi et al. (2021) presented a tour-de-force of comparativ…