A number of researchers are trying to determine the oldest animal on the planet. The result, they claim a simple sea sponge is the first animal to be present on Earth.

Quoted from The Independent on Wednesday (29/2/2106), researchers at the Massachusetts Institute of Technology (MIT) say that a marine sponge existed long before the Cambrian 'explosion', an evolutionary period that began about 540 million years ago.

At that moment, suddenly appeared so many new types of ancient animals.

The MIT team revealed it after analyzing molecular fossils, from molecules found in ancient rocks and surviving today.

In particular there is a rare molecule called 24-Isopropylcholesterol (abbreviated to 24-IPC) found on rocks aged 640 million years. Apparently, the same molecule is also produced by today's marine sponges.

As a follow-up to these findings, David Gold's team tries to find the genes responsible for generating 24-IPC, as well as the search for the organism that carries the gene, and when its development becomes its carrier organism.

From gene analysis in 30 different organisms, the team conical to a single gene, sterol methyltransferase (SMT), which can cause an organism to produce 24-IPC if the organism has the correct number of copies of the gene.

The researchers found that marine sponge and algae species had the correct number of SMT copies to be able to produce 24-IPC.

Through the analysis of these genes and making evolutionary tree charts based on fossil records, they found that the marine sponge produced the molecule in question long before the algae produced it as well.

According to the researchers, sea sponges reached this important point about 640 million years ago - similar to the formation of rocks containing 24-IPC.

This study provides strong evidence that sea sponges appeared on Earth much earlier than any other animal. Nevertheless, David Gold argues that this discovery raises new questions.

"What is the shape of this organism - what kind of environment 640 million years ago? And why is there a long time lag in the fossil record?" beber Gold.

"This shows that there is still much we do not know about the early life in animals, how many more findings are left, and how useful these molecular fossils are to fill in the pauses when they are done correctly."