Originally it was assumed that the origin and evolution of life took several billion years. But in recent times this presumption has been greatly reduced, and many scientists believe that life was created in a very short time. However, finding evidence to support this theory even with our modern technologies is a very difficult task. The geological record of the early Archean is sparse, and there are very few rocks that are more than 3.5 billion years old. The rocks with ages greater than 3.5 billion years, that are preserved, have been extensivily altered by metamorphic proccesses (van Zuilen et al. 2002), and thus any direct evidence of ancient life has apparently been largely destroyed. In the few rocks that do have evidence for early life, there is much dispute about whether these microstuctures are adequate. However, assuming that the evidence is correct, the Archean Earth was teeming with prokaryotes, and that the origin of life must have taken place as soon as the conditions were suitable to permit the survival of these types of organisms. An example of the evidence supporting this theory includes the sulphur isotope investigation of the 3.4 billion year old Dresser Formation in Australia. The investigation indicates biological sulfate- reducing activity (Shen et al. 2001), an affect occuring in marine enviorments inhabited by large amounts of anaerobic photosynthetic prokaryotes (Tice and Lowe 2004).
The Early Archean fossil record speaks for a relatively short timescale required for the orgin and early evolution of life on earth and suggests that the critical factor that must have been present was liquid water, which became possible as soon as the Planet's surface finnally cooled below boiling point. Unfortunatly, there is no geological evidence of the enviormental conditions on the early earth at the time of the origin of life, neither is there any molecular or physical preserved to provide imformation of the proccess the proceded the appearence of the first cellular organisms. We have no idea of what the temperatures, Ocean PH's, and other general enviormental factors were present painting us a very vague picture of the origin of life. What we do know is that life began somewhere in between the time when the earth finnally cooled and the 3.4 billion year old Dresser Formation in Australia.
