Scientists studying the commonality of the genomes of living organisms traced back the tree to the earliest living creature common to modern life and discovered it emerged just 300 million years into the planet’s 4.5 billion-year existence, a discovery that greatly changes understanding of early life.
According to About Science, the last universal common ancestor, or LUCA, was likely a single-celled nucleus-missing organism similar to a prokaryote, but the emergence of the organism comes about 700 million years before the oxygen-rich atmosphere we live in now formed, meaning early life survived in a varying environment.
The revelation could also switch how scientists and astrobiologists search for life in alien worlds, with an understanding that an oxygen-depleted environment does not necessarily eliminate the possibility of life.