Vijayan, M (1988) Molecular interactions and aggregation involving amino acids and peptides and their role in chemical evolution. In: Progress in Biophysics and Molecular Biology, 52 (2). pp. 71-99.
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The earth is believed to have originated some 4.5 billion years ago. The surface of the nascent earth was devoid of any trace of organic matter, let alone life. It is at present characterized by a rich variety of different forms of life. How did this come about? How did life originate and evolve into innumerable forms? The answer to this question is generally attempted in two phases. First, how did the molecules of life come into being and organize themselves into a primitive self-replicating system or primitive cell? Secondly, how did the present-day organisms evolve from the primitive cell or cells? The first question is concerned with chemical evolution and the subsequent origin of life, and the second with biological evolution. It may be noted that chemical evolution must have taken place in a comparatively short span of time on the geological time scale. There is evidence to suggest that life existed as early as 3.6 to 3.8 billion years ago (Nisbet, 1985). The earth, after its formation some 4.5 billion years ago, must have taken several hundred million years to cool down sufficiently for the formation of the crust and to be able to support water and organic matter on its surface. Allowing for this time lag and bearing in mind that life probably originated some 3.6 to 3.8 billion years ago, chemical evolution appears to have been completed in a few hundred million years in the early phase of earth's existence. No traces of the processes of chemical evolution remain. Therefore, direct answers to questions concerning chemical evolution cannot be obtained. Results of informed speculation, simulation experiments, observations of meteorites etc., need to be put together even to get a blurred picture of chemical evolution. Indeed such a picture, partly clear and partly hopelessly confusing, has emerged during the last few decades.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier Science.|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit|
|Date Deposited:||19 Feb 2008|
|Last Modified:||19 Sep 2010 04:42|
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