Scientists have discovered a lost world that could unravel the story of the evolution of life on our planet. These ancient organisms inhabited the underwater world over 1.6 billion years ago and are the source of the evolution of animals, plants, and even us. Known as Protosterol Biota, the microscopic organism belongs to a family of organisms called eukaryotes, which have a complex structure combining mitochondria, known as the “powerhouse” of the cell, and a nucleus that acts as the “control and information center.” The fossils discovered by the scientists were found in rock from the ocean near Australia’s Northern Territory.
The discovery was made by examining fossil fat molecules within the 1.6-billion-year-old rocks. The fossil molecules possessed a primordial chemical structure that hinted at early complex creatures that developed before the Last Eukaryotic Common Ancestor (LECA), the ancestor of modern fungi, plants, animals, and single-celled organisms.
These proto-eukaryotes were gate-crashers in a world teeming with bacteria, simpler unicellular organisms that lack a nucleus. But unlike bacteria, they had a nucleus that allowed them to control their metabolisms and evolve into multicellular creatures that eventually gave rise to animals, plants, and humans.
Scientists believed that these proto-eukaryotes must have been extremely powerful for their size and should have conquered the world’s ancient oceans, but their physical remains have remained rare. Instead, Earth’s ancient oceans tended to look like a bacterial broth.
However, it turns out that these prehistoric creatures had a strategy for dealing with the bacteria in their ecosystems. They developed a chemical defense system that tethers the mitochondria to the nucleus to allow the nucleus to control the mitochondria’s metabolism. This allowed the proto-eukaryotes to evolve into highly sophisticated multicellular organisms and helped them survive in a world otherwise dominated by bacteria.
A similar phenomenon was observed during the Devonian Period, a time of significant global changes that saw the formation of Euramerica and Gondwana. The first animals emerged in a world of soft-bodied aquatic creatures called Ediacarans in this period. These creatures had rudimentary arms with feather-like structures used to rake the seabed for food. They also had bilateral symmetry, which means the left and right sides of their bodies were mirror images of each other.
In the next step of their evolution, these eukaryotes took on harder, sturdier body shells and gained more complicated organ systems. At this point, they became able to use their specialized metabolisms to make longer-chain molecules such as proteins and DNA, which are vital for life.
This process is known as gene duplication. During this phase, the genes are copied and then separated into distinct strands, each of which can be inserted into a new cellular location. During this evolutionary process, the DNA strands can acquire more and more instructions, which leads to the formation of a new, complex, and more evolved organism.
