Scientists discovered some sedimentary rocks in central India which might be hosting world’s oldest plant-like fossils. They estimate that these fossils are around 1.6 billion years old and contain similar structures to those found in red algae.
These are not the oldest fossils on Earth, as there are others who are dated back 3.5 billion years. However, these do not resemble plants. They are unicellular organisms without nuclei or other cell-like structures called organelles.
The new fossils resemble algae
Scientists identified two types of new fossils and they both resemble red algae. One type contains filaments, while the other one has more robust structures. These fossils are 400 million years older than the previous algae-like discoveries, which suggests that multicellular life started evolving much earlier that the scientists used to think.
Algae are a part of the eukaryotes group, where all organisms have organized cells which contain a nucleus. Although they are also involved in processes of photosynthesis, algae are not classified as plants. Instead, they belong to the protists group, which includes both unicellular and multicellular organisms.
Red algae also bear the name of rhodophytes and they can be found along the coasts and the continental shelves of oceans. These types of algae are well-known for the “red tides” they produce. Such a phenomenon occurs when the algae multiply in large numbers and they make the water look like it is red.
However, too many red algae are dangerous for the marine ecosystems. When they multiply in such large numbers, they produce some toxins called blooms. These toxins can produce massive die-offs if fish and animals consume them.
Where did the scientists find these fossils?
The fossils were discovered in an Indian region that was formerly a shallow sea. They were organized in thin sheets of microbial organisms kept in rock. The scientists used powerful X-rays to analyze the organisms and discovered that their cellular composition resembled algae, namely the diamond structures that algae used for photosynthesis.
The previous oldest known algae fossils were only 1.2 billion years old. Thus, this discovery represents the oldest sample of eukaryotic life. Since fossils of early eukaryotes are so rare, the researchers burst with excitement when they observed the cellular structures in their findings.