A genetic analysis of 640-million-year-old rocks showed that the sea sponge may have been the first animal to develop on Earth, which puts the humble species as the potential ancestor of all animal life.

In a large study, scientists from the Massachusetts Institute of Technology in Cambridge determined that the ancients rocks contained molecules produced by sea sponges.

This old rocks significantly predate the Cambrian explosion, the period 540 million years ago in which most animal groups took over the planet, suggesting that sea sponges may have been the first to arrive, as reported by The Christian Science Monitor.

The natural sea sponge is one of the world’s simplest multi-cellular living organisms. Credit: Sea Sponge Company

“We brought together paleontological and genetic evidence to make a pretty strong case that this really is a molecular fossil of sponges,” explains David Gold, a post-doctoral researcher in MIT’s Department of Earth, Atmospheric, and Planetary Sciences (EAPS), in a press release.

There is an estimate of about 8.7 million species of animals on Earth, according to scientists, but in the beginning there could had been only one and the recent study showed that sea sponges may be it.

The recent discovery just generated new questions and show how little humankind actually know about early animal life, said gold. What did these organisms look like? What was the environment like? and why is there a big gap in the fossil record?

Those are a few of the just found question to answer after the added information to hypotheses that have been studied for years. Gold highlights the importance and usefully of the molecular fossils found to fill in those gaps.

A long road

Researchers, like EAPS Professor Roger Summons, have spent decades searching for the animal kingdom’s complicated evolutionary tree. His team have been looking tirelessly for clues in molecular fossils, trace amounts of molecules that have survived in ancient rocks long after the rest of an animal decayed.

In 1994, a new hypothesis came to the surface and was called “‘sponge biomarker hypothesis”, which was partially confirmed in 2009. Now, the theory has been empowered with more data from the genetic testing by Dr. Gold, said Summons.

He added that Dr.Gold’s study adds a further layer of evidence supporting the theory that sponges or their ancestor might be the greater source.

Source: The Christian Science Monitor.