Chinese scientists have finally uncovered clues to a mystery surrounding fossils excavated in the provinces of Zhejiang and Yunnan, providing anatomical and fossil evidence that the origin of the trachea in vertebrates is derived from gills.
Illustration. (Source: livescience.com)
A new study conducted by scientists from China, Sweden, and the UK reveals that the human middle ear evolved from fish gills.
According to researcher Gai Zhikun from the Chinese Academy of Sciences and the first author of the paper entitled “The Evolution of the Respiratory Region from Jawless Fish to Tetrapods,” there is substantial evidence from embryos and fossils indicating that the human middle ear evolved from the breathing holes of fish.
However, the origin of these breathing holes has puzzled scholars for over a century. The fossils were taken to Switzerland for imaging scans and 3D structure reconstruction.
Researcher Gai stated that this discovery helps explain why the human ear and mouth are connected, through a breathing passage that has been inherited from the mouth through the gills of fish.
This scientist explained that this is an evolutionary remnant of fish from more than 400 million years ago, which we now refer to as the Eustachian tube (the tube connecting the middle ear to the throat, responsible for equalizing ear pressure and draining excess fluid from the middle ear).
