Question: what was the first form of life on earth???

Tiffany Taylor answered on 14 Jun 2012:

First (somewhere between 4.5 billion and 4 billion years ago), there was just RNA (which is single stranded DNA), a molecule which can carry genetic information and make copies of itself. It was not carried in a cell but just floating about. Evolution acted on these simple molecules just as it acts on us today. Overtime, these evolved into DNA and were package up (in what we call a membrane). The beginnings of the first cell.
The first simple cells came into existence about 3.8 billion years ago (that’s 3,800,000,000 years ago). These cells were very basic, they used carbon dioxide as food, and converted it into carbon and oxygen. This increased the amount of oxygen in the air (and decreased carbon dioxide), which made the environment better for other things to live. So without them we wouldn’t be able to live. The earliest life didn’t do much more than take in carbon dioxide and divide, the key was that they had a very simple genetic system which allowed them to pass on genes, and so evolution could, overtime, make them better and more complex.