(ORDO NEWS) — The earliest representatives of the animal kingdom appeared on our planet more than 550 million years ago, and until now, scientists did not know what exactly they ate.
In the Ediacaran period, the Earth was inhabited by the first multicellular organisms, which looked very strange not only by the standards of modern animals, but in comparison with later Cambrian animals.
Some of them in certain ways resembled animals familiar to us: for example, they had a mouth and intestines for digesting food. Others in terms of nutrition were like mushrooms.
Of course, it is difficult to say what such ancient animals could eat: their soft tissues rarely fall into the paleontological record, and there is nothing to say about the contents of the intestine.
However, in 2018 Australian National University , discovered a 575-million-year-old kimberella fossil among the steep cliffs on the White Sea coast , whose chemical composition provided clues about the animal’s diet.
An international team of researchers have identified phytosterol molecules in the remains of Kimberella , which are part of the plant cell membrane ( cholesterol plays the same role in mammals ).
Since animals do not produce this substance, the scientists concluded that the slug-like kimberella scraped microscopic algae from the seabed, which it absorbed through the mouth and digested in the intestines.
Another animal lived side by side with the kimberella dikinsonia grew to 1.4 meters in length and was perhaps the largest living organism of its time.
Crawling on the sea floor, this ribbed creature, like an elongated pancake, absorbed nutrients from the entire surface of the body, so that it had to grow wide but thin to satisfy its appetites.
Feeding on algae is energetically more beneficial than simply absorbing free nutrients from the water. So in this respect, Kimberella was a more advanced creature than the huge Dickinsonia.
Nevertheless, both of these primitive animals died out by the end of the Ediacaran period, after which new forms of life, already more similar to modern ones, captured the ancient seas of the Earth.
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