As Stephanie Pappas writes, it’s much more complex than we might think:
In 2013, researchers from the Integrated Ocean Drilling Program reported at the annual Goldschmidt Conference in Italy that they’d found microbes in 100-million-year-old sediments in the floor of the deep sea, according to the BBC. The microbes were reproducing once every 10,000 years, such a slow rate that scientists weren’t sure if they could really call the microbes “alive.” More.
But surely that is a technicality. If they reproduced at all, they are alive. The issues she raises around very old organisms that have remained extant through cloning may be more meaty.
We are getting somewhere if we can determine that something is definitely alive without necessarily coming up with a hard definition. Now here’s one: Are viruses alive?
See also: Another stab at whether viruses are alive
Phil Sci journal: Special section on understanding viruses
Why “evolution” is changing? Consider viruses
The Scientist asks, Should giant viruses be the fourth domain of life? Eukaryotes, prokaryotes, archaea… and viruses?
Are viruses nature’s perfect machine? Or alive?