Community College (LRCCD)

Geology & Earth Science Instructor: Arthur Reed, P.G.



Happy Fossil Friday!

Friday June 25, 2021



Fossils from Cambrian, tough enough to survive as a species to the end of Earth?!



Tardigrades, are known colloquially as water bears or moss piglets. Fossils of nearly identical creatures have been found from the Cambrian period over 500 million years ago, when the first complex animals were evolving. And, ever since they were discovered in 1773 by German pastor Johann August Ephraim Goeze it has been clear they are special. 


These particular fossils (≈1.5 mm) show us the very patchy fossil record of tardis must be due to them not fossilize easily.


The earliest known true members of the group are from Cretaceous (145 to 66 million years ago) amber found in North America, but are essentially modern forms, and therefore likely have a significantly earlier origin, as they diverged from their closest relatives in the Cambrian over 500 million years ago.


The above fossils were embedded in limestones, and thus could eventually be recovered by etching them out of the rock in which they were found using weak acids, as the fossils (replaced now by fluoritic apatite) do not dissolve.


The biggest adults may reach a body length of 1.5 mm, the smallest below 0.1 mm. Newly hatched tardigrades may be smaller than 0.05 mm.


Tardigrades have survived all five mass extinctions, laboratory temperatures from near absolute zero to 150C, and atmospheric vacuum and cosmic radiation on the outside of a spaceship. This fits into the hypothesis some scientists hold that life may have traveled on debris between our planets in the past.



Adapted from:

Russell Garwood


University of Manchester, UK





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