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The answer to a centuries-old mystery has been found: Scientists finally find out what the first animals looked like

Ihor Romanko

What the first multicellular animals looked like
What the first multicellular animals looked like. Source: theconversation.com

Researchers have recently found an answer to the long-standing mystery of the first multicellular animal on Earth, discovering that comb jellyfish (ctenophores) surpass sponges as the oldest living organisms, even though they look like distant relatives of true jellyfish. This new discovery shows that evolution does not always lead to greater complexity. The study was published in Nature.

Read also: A ball of frozen fur found in Canada turned out to be a mummified animal 30 thousand years old

Sponges (Porifera) were considered to be candidates for the role of the "first" organisms due to their simplicity of structure, including the absence of a nervous system. However, genetic studies have shown that comb jellyfish are more likely to be the first organisms, despite the fact that they have a more complex nervous system.

Anatomically, some sponge cells are very similar to the cells of single-celled microbes called choanoflagellates. Source: sciencealert.com
Anatomically, some sponge cells are very similar to the cells of single-celled microbes called choanoflagellates. Source: sciencealert.com

By comparing the genetic sequences in the genomes of different organisms, the researchers found high similarity between sponges and more modern animals, indicating a similar evolutionary path. However, differences were found in comb jellyfish, indicating that they split off before further evolutionary events.

As with all comb jellies, the California sea gooseberry has eight sets of cilia running down its sides, which they use to swim in search of food. Source: sciencealert.com
As with all comb jellies, the California sea gooseberry has eight sets of cilia running down its sides, which they use to swim in search of food. Source: sciencealert.com

These discoveries confirm that scallops branched first, and then sponges appeared, passing on their new chromosomal structure to their descendants. The new research methods developed by the team will help to explore other evolutionary mysteries within the depths of time.

Earlier, we wrote about how scientists managed to create a bioprinter that can print artificial skin on the cheap.

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