About 4 billion years ago, Earth began to show signs of the conditions that allowed the first cells to take hold and populate ...

Were there already viruses on Earth when the first living cells appeared billions of years ago? – Aayush A., age 16, India How life on Earth started has puzzled scientists for a long time.

The research team reasoned that for cells to get their start on early Earth, some form of cell boundary must have formed first to protect ... but did appear to be capable of serving as a sort ...

Until now, it’s been very hard for scientists to establish a detailed timeline of the early evolution of bacteria.