This argument from the article meshes with my own thinking:
The reason there have not been new forms of life originating on Earth, evolving alongside our microbial cousins, could be that there is simply no room for a newcomer. In a system where every niche is filled with more advanced life looking for a next meal, even if a new form of life got started, it would not last long.
There are a number of related issues regarding life, including LUCA and the emergence of mitochondria in eukaryotic cells, which suggest to me less that a single ancestor existed at that time than that that ancestor's descendents out-competed (or out-lucked) all other comers, and that once established other contenders for life simply couldn't find an available niche.
Oh, and bad news for the fans of LGM / panspermia, at least in the "absence of evidence" sense:
Population statistics indicate that the microorganisms originated from terrestrial contamination during the sample preparation stage rather than being indigenous to the asteroid.
The reason there have not been new forms of life originating on Earth, evolving alongside our microbial cousins, could be that there is simply no room for a newcomer. In a system where every niche is filled with more advanced life looking for a next meal, even if a new form of life got started, it would not last long.
There are a number of related issues regarding life, including LUCA and the emergence of mitochondria in eukaryotic cells, which suggest to me less that a single ancestor existed at that time than that that ancestor's descendents out-competed (or out-lucked) all other comers, and that once established other contenders for life simply couldn't find an available niche.
Oh, and bad news for the fans of LGM / panspermia, at least in the "absence of evidence" sense:
Population statistics indicate that the microorganisms originated from terrestrial contamination during the sample preparation stage rather than being indigenous to the asteroid.