Were Sea Sponges The Animal That Sparked Evolution On Earth?

  • Mary Nichols , Design & Trend Contributor
  • Feb, 29, 2016, 03:15 AM
Tags : science
Sea Sponge
(Photo : Getty Images/Donald Miralle) Scientists may have identified the animal that sparked the evolutionary tree.

It is believed that there are 8.7 million species of animals on in existence on Earth, all life began with just one.

A new study by researchers at the Massachusetts Institute of Technology in Cambridge suggests that the first animal on Earth was a sea sponge, writes Christian Science Monitor.

A team of scientists carried out a number of genetic tests on trapped molecules found in 640-million-year-old rocks. They found that sea sponges likely produced the molecules found in the ancient rocks, which predate the Cambrian explosion when most animal groups began to establish themselves on Earth. The age of the samples suggests that sea sponges could have been the first animals to develop on Earth.

The researchers wrote that the study offers "the oldest evidence for animal life."

"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.

Establishing the type of animal that spurred the evolution of animals has long been a puzzle for paleontologists. Many fossils dating back to the beginning of the Cambrian have been discovered, however fossils from prior to this are unusual.

EAPS Professor Roger Summons has spent much of his career looking for the animal that sparked the evolutionary tree - looking for evidence in molecular fossils. These are trace amounts of molecules that have become trapped in ancient rock samples.

The "sponge biomarker hypothesis", which suggests that sea-sponge may have been the first animal to develop, was conjectured in 1994 before being partly confirmed in 2009. The theory is based on 24-isopropylcholestane, a lipid molecule, or sterol, that is present in unusually high amounts in rocks dated back to the Cambrian as well as those that are older.

According to Dr. Summons, a "further layer of evidence supporting" the hypothesis that sponges could be the evolutionary source of animals comes from the genetic testing carried out by Dr .Gold.

The recently published study strongly suggests that sea sponges were present on Earth 640 million years ago - long before other life forms emerged.

"This brings up all these new questions: What did these organisms look like? What was the environment like? And why is there this big gap in the fossil record?" Gold said in a press release. "This goes to show how much we still don't know about early animal life, how many discoveries there are left, and how useful, when done properly, these molecular fossils can be to help fill in those gaps.

The study was published in the journal Proceedings of the National Academy of Sciences.

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