Stromatolites

Earth's Oldest Houses          ( Heritage Listed - Not for Sale )

Builders : Plant and Bacteria Construction Group Inc.

Fossil evidence of the oldest life form yet found on Earth is that of Cyanobacteria, a mix of blue-green algae (plant) and bacteria (animal) (researchers are still sorting out just how much is plant, and how much is animal !!). They look like long, thin threads.

The fossil evidence has been dated as 3,500,000,000 (3.5 billion) years old
and was found inside Cyanobacteria's house constructions, which we call Stromatolites.
It was found at North Pole in Western Australia (yes, there is such a place in Australia -
Click here to see where it is).

They are believed to be Earth's first
'home builders'!!

Cyanobacteria are still living today, and building their 'houses' in exactly the same way as researchers believe their ancestors did,
3.5 billion years ago.

This is their story :

They live in the warmer, shallower areas of the ocean - usually bays - growing upwards through the sand and silt grains that land on top of them. As they do this, they mix lime (which they manufacture) with the grains. This hardens into a limestone rock, and becomes their 'house' -
a Stromatolite.

Because they live in groups, their combined building activity creates a rather large 'house' .. and as more and more groups build 'houses', the area they occupy in the bay becomes rather large, too. It becomes a reef.

(Actually, this is very like our own living
arrangements - but we call them suburbs and cities!)

Today, there are not as many Cyanobacteria building their Stromatolites as there were
3.5 billion years ago, because climate and tectonic changes have destroyed most of the places where they prefer to live.

But a few sites still remain, and one of these is at Shark Bay in Western Australia ( click here to see where it is).

The following photographs show what they look like now (the photos were taken in 2001) ... the same, researchers feel, as
3.5 billion years ago.