CANBERRA, Nov. 23 (Xinhua) -- Australian scientists have discovered the diets of the earliest animals known to inhabit Earth.

In a study published on Wednesday, researchers from Australian National University found that Ediacara biota, a group of large, soft-bodied organisms that lived between about 600 and 540 million years ago, ate bacteria and algae sourced from the ocean floor.

By analyzing fossils that contained the molecular remains of their last meal, researchers confirmed one organism, known as Kimberella, had a mouth and digested food in the same way as modern animals.

Another species, the Dickinsonia, grew up to 1.4 meters long and absorbed food through its body as it traveled along the ocean floor.

The two organisms lived approximately 20 million years before the Cambrian explosion, a major diversification event that changed the course of evolution and resulted in modern animals.

"Our findings suggest that the animals of the Ediacara biota, which lived on Earth prior to the 'Cambrian Explosion' of modern animal life, were a mixed bag of outright weirdos, such as Dickinsonia, and more advanced animals like Kimberella that already had some physiological properties similar to humans and other present-day animals," Ilya Bobrovskiy, lead author of the study, said in a media release.

"Ediacara biota really are the oldest fossils large enough to be visible with your naked eyes, and they are the origin of us and all animals that exist today. These creatures are our deepest visible roots."

Both the Kimberella and Dickinsonia fossils were retrieved by Bobrovskiy from cliffs near the White Sea in Russia in 2018.