A geologist from Canada says he found the oldest fossil record of animal life on Earth in an article published Wednesday in Nature. It is believed that the remains of prehistoric sponges may survive in mineral deposits found in an area of northwest Canada characterized by steep mountains around a billion years ago.
Elizabeth Turner, a geologist, discovered the rocks in a remote area of the Northwest Territories reachable only by helicopter, where she has been mining since the 1980s. Furthermore, she said that thin parts of rock contain three-dimensional structures that look like modern sponge skeletons.
An agrobiologist and expert in sponges at the University of Gottingen, Germany, Joachim Reitner, said that he believes these are antique sponges. The dating of end-to-end layers specifies the samples are around eight hundred and ninety million years old, which would make them around three hundred and fifty million years older than the oldest undoubted sponge fossils formerly found.
What first animal groups included?
An expert on sponges at Sweden’s Uppsala University, Paco Cardenas, said that the most stunning thing is the timing. To discover sponge fossils from close to nine hundred million years ago will significantly improve the understandings of the experts of early animal evolution. Several scientists believe the primary animal groups included sponge-like or soft sponge creatures with the deficiency of nerves and muscles but have other features of ordinary animals such as cells with differentiated sperm and functions.
Definitely, there is minimal scientific consent or certainty about whatever dating back a billion years ago. Therefore, other scientists will possibly continue to examine and debate the findings of Turner. According to the belief of scientists, life on Earth emerged nearly 3.7 billion years ago. The initial animals appeared much later, but exactly when is still questionable.
However, scientists using a line of perceptive called the molecular clock – where they examine the rate of genetic mutations to backdate when two species of animals probably departed – say that available indication points to sponges evolving much earlier, about a billion years ago. But, until now, no supporting physical evidence found about this theory.
The dating of eight hundred and ninety million years ago is significant because, after the confirmation of the identification of the sponge, it shows that the first animals evolved before a period when oxygen in the ocean and atmosphere reached a level experts once thought was essential for animal life. So far, some recent research shows that some sponges can live with a very small amount of oxygen.