The first animal that appeared on Earth, was likely a simple marine sponge. New genetic research conducted by MIT confirmed that the sea sponge is a source of interesting molecules found in rocks, of which 640 million years. These rocks significantly predate the Cambrian explosion — the period in which most groups of animals inhabited planet 540 million years ago. Presumably, sponges were the first animals that inhabited the Earth.
Paleontologists have unearthed a huge number of fossils from a period beginning roughly 540 million years ago. Some scholars have argued, based on these fossils that modern groups of animals, in essence, as “Bang” burst on the Ground, very quickly developing from unicellular organisms to complex multicellular animals in a relatively short geological time interval. However, fossils are known until the Cambrian explosion, strange in many ways, were extremely difficult to determine what the type of animal, which was the first in the evolutionary line. Their genome compared with the genomes of 30 organisms.
“We combined paleontological and genetic evidence to have a pretty strong case that it is really a molecular fossil sponges, says David gold, a postdoc in the Department of Earth, atmospheric and planetary Sciences (EAPS) at MIT. Is the oldest evidence of animal life”.
Comparing the genomes, they identified one gene, the Sterol methyltransferase or SMT, responsible for the production of certain types of Sterol. The researchers found that sea sponge and algae some species have similar genome with an additional copy of the SMT gene, which produces 24-IPC. In particular, 24-isopropylmalate found in stones from Oman age 640 million years. The study showed that this gene sponge previously received algae.
Thus, based on the acquired results, the scientists put forward the theory that sponges inhabiting the deep sea, are the oldest animals on Earth (Precambrian period). The researchers compared the copy to determine how they were related and when each copy of the gene first appeared. Then they did a scheme of relationships on the evolutionary tree and used evidence from the fossil record to determine when each copy genes SMT.
Regardless of how they estimate the timing on the tree of evolution, the researchers found that the sea sponges have evolved an additional copy of SMT much earlier than algae, and they did it, apparently, 640 million years ago — the same time period was found when 24-IPC in rocks.
Their results give strong evidence that sponges appeared on Earth 640 million years ago, much earlier than any other life form.
“These studies raise new questions: what do these organisms look similar, what was the environment and why there is such a large gap in the fossil record?” says David gold.
According to the materials technology.org