Paleontological fossil of Kimberella worm. Image source: Australian National University
Recently, scientists at the Australian National University discovered the world’s oldest meal. In the last meal consumed by the earliest known animals that inhabited Earth 558 million years ago, researchers have unearthed new clues about the physiology of the earliest animals. The findings were published in the journal Current Biology.
The Ediacaran biota is the world’s oldest large biota, existing between 575 million and 541 million years ago. The researchers found that the animals were eating bacteria and algae from the seafloor.
Researchers analyzed ancient fossils containing preserved molecules of phytosterols, a type of fat found in plants, left over from an animal’s last meal. The researchers found that the slug-like organisms, known as Kimberella worms, looked a bit like molluscs, with shell-like bodies up to 15 centimeters long. The creature had a mouth and gut, and digested food in the same way modern animals do. This feature suggests that it may have been one of the most advanced organisms on Earth at the time, the researchers said.
The team found that another animal was 1.4 meters long and had a rib-like design on its body, but it was less complex and lacked eyes, mouth and intestines. Known as the Dickinsonia, this strange creature absorbs food through its body.
“Our findings suggest that animals in the Ediacaran biota that lived on Earth before the ‘Cambrian Explosion’ ranged from strange creatures like Dickinsonia to More advanced animals like Kimberella worms already have some physiological properties similar to humans and other modern animals,” said lead author Dr Ilya Bobrowski from Potsdam, Germany.
Kimbera worms and Dickinsonia are both part of the Ediacaran biota, and their structure and symmetry are unlike anything in existence today.
Algae, which are rich in energy and nutrients, may play an important role in the growth of Kimberella, which may explain why the organisms in the Ediacaran biota are so large, the researchers said. Almost all fossils that came before it were single-celled organisms, small in size. The research will help scientists trace the evolution of the earliest animals, and how they were related to their descendants.