[CraigS]

It appears that the supposed oldest examples of life on our planet -- 3.5 billion-year-old bacteria fossils found in Australian rock called Apex Chert -- are nothing more than tiny gaps in the rock that are packed with minerals.

Tea-leaf gazing I hear you say, eh ?

Source: Research overturns oldest evidence of life on Earth

“Bacteria are basically little bags of goo, and they’re not easily fossilized,” said Alison Olcott Marshall. “The idea that you would have this tiny bacterium preserved for 3.5 billion years is not very likely to happen. The second problem is that they are morphologically so simple — they’re just circles and rods. There are lots of things in nature that make circles and rods.”
...“This work has direct implications for looking for life on Mars,” said Craig Marshall. “If we’re having problems here with ancient Earth sediments and there’s a huge debate, we want to try and be more stringent with our analytic techniques. We don’t want a repeat of the announcement in 1996 that, ‘Wow, we found life on Mars.’ I can’t recall the timeframe of how many days or weeks until they said, ‘Well, maybe we haven’t.’ If we tighten up our ways of looking for ancient biology, this is going to be very applicable for Mars, particularly the ExoMars European mission in 2018 that will take on board a Raman spectrometer.”

This is interesting in the light of the recent declaration by Richard Hoover, and his conclusions about finding 'life' from what he says are fossilised cyanobacteria filaments.

In spite of the too-ing and fro-ing, at least its good input for the forthcoming hype when they find something unusual on Mars .. (a foregone conclusion, it seems).

A parting quote …

The second problem is that they are morphologically so simple — they’re just circles and rods. There are lots of things in nature that make circles and rods.”

Cheers