July 1, 2010
A new study in Nature identifies apparently multicellular fossils discovered in Gabon in Africa that date back 2.1 billion years, a full 1.6 billion years before the Cambrian Explosion when most complex multicellular life was thought to have emerged. While no organic material remains on the fossils, scientists will try their best to determine whether they represent a true multicellular organism or simply a colony of single celled bacteria.
The dating of the fossils lines up with the Great Oxidation Event, a sudden evolution of photosynthesizing bacteria that led to a rapid change of the Earth’s atmosphere from nearly oxygen free to the breathable air today. This change could have made a ripe environment for the evolution of multicellular life.
However, paleontologist Philip Donoghue points out that the organisms represented in the fossils may not be related to the mulitcellular life of today:
Importantly, even if these fossils are the oldest-known multicellular organisms, that doesn’t mean they were the ancestors of all multicellular life, Donoghue said. “Multicellularity hasn’t evolved just once; it’s evolved almost 20 times even amongst living lineages,” he said. “This is probably one of a great number of extinct lineages that experimented with [increased] organismal complexity”
For more, see the story from Discover Magazine.