Salamanders are fascinating creatures that have drawn plenty of spotlight from biologists due to their significant position in our evolutionary path. These are amphibians, and it was no coincidence that they drew attention, as a missing piece between creatures of water and that of land, from scientists in the 19th century, inspired by the recent theory of evolution.
In one such pursuit, what the famous zoologist and the Professor at the Museum of Natural History in Paris, Auguste Dumeril, found provides a live example of the wonders of repurposing animal functions.
In 1864, Dumeril received six salamanders from a lake in Mexico. They were large adults with feathery gills and aquatic body shapes characteristic of life in water. He kept them together and even had them produce fertilised eggs. The children that came out of the cage shocked the researcher; they showed little resemblance to their parents. No gills and aquatic tail; they appeared like the terrestrial variety.
It was found out much later that there are two pathways of development for the salamander larvae, according to the surrounding environment. The salamander in the aquatic habitat goes through the default pathway, but the one on land undergoes this metamorphosis. We now know the change gets triggered by the amount of thyroid hormone in the bloodstream that activates or kills some cells. Same gene, same creature but a change of environment yielding dramatic change in the appearance of the end product!
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Some assembly required: Neil Shubin
