But the dominant theory nowadays is that primitive microorganisms first assembled in hot, chemical-rich water at hydrothermal vents at the bottom of the ocean.
One reason for favouring this marine model is that fossil evidence of early land-based microbial life has been lacking.
These changes typically occur so slowly that they are barely detectable over the span of a human life, yet even at this instant, the Earth's surface is moving and changing.
As these changes have occurred, organisms have evolved, and remnants of some have been preserved as fossils.
For example, uranium will radioactively decay through a series of steps until it becomes the stable element lead. The original element is referred to as the parent element (in these cases uranium and potassium), and the end result is called the daughter element (lead and argon).
The straightforward reading of Scripture reveals that the days of creation () were literal days and that the earth is just thousands of years old and not billions.
Czaja and his colleagues wanted to know what might have been lurking in much deeper parts of the sea.
There are certain kinds of atoms in nature that are unstable and spontaneously change (decay) into other kinds of atoms.Until recently, the oldest evidence of life on land was only 2.8 billion years old, whereas the oldest evidence from the sea was 3.7 billion years old.Now, a team led by Tara Djokic at the University of New South Wales in Australia has discovered fossils of land-based microorganisms.They were found in 3.5-billion-year-old rocks in an extinct volcano in the Dresser Formation in the hot, dry, remote Pilbara region of Western Australia.The fossils include stromatolites – layered rock structures created by microorganisms – and circular holes left in the rock by gas bubbles that look like they were once trapped by sticky microbial substances.