The Problem of Stages in Biopoesis 



J. D. BERNAL 



Birkbeck College, University of London, England 



As THE very calling of this Symposium indicates, the question of the origin 

 of life can only be investigated by a combined effort in which experts in many 

 fields co-operate. Every solution put forward by an individual, however well- 

 read or brilliant, is bound to be a partial one and open to criticism because of its 

 reliance on ideas or supposed facts drawn from regions of knowledge with 

 which that individual is not directly acquainted. These faihngs can in the course 

 of time be removed by mutual criticism, but the process is very slow and one of 

 our hopes is that the present Congress will act hke a catalyst and speed it up. 

 However, with multiplicity of counsel there is another danger arising from 

 different scientific formation of the participants and different ideas of the 

 nature of the problem to be solved. By dealing separately with different aspects 

 of the Origin of Life their sequence and inter-relatedness may be overlooked. 

 It is on this last point that I would hke, in this paper, to put forward some sug- 

 gestions as to the general pattern of the Origin of Life, and in particular to try 

 to block out some formal account of the stages in which it may be deemed, 

 provisionally, to have taken place, in order to focus attention on the problems 

 that may occur at each stage. I am not suggesting that my pattern is the correct 

 one or that it may not require drastic modification, but I do urge that it is better 

 in such a Congress to have before it some pattern than none. At any rate it has 

 helped me to construct one, and my ideas may be useful even if they only provoke 

 contradiction. 



In general the pattern I propose is one of stages of increasing inner complexity, 

 following one another in order of time, each one including in itself structures 

 and processes evolved at the lower levels. The division into stages is not in my 

 opinion an arbitrary one. Although the evolution of life was continuous, for no 

 stage could have been completely static, it cannot have been uniform. Discon- 

 tinuities which occurred at later stages of organic evolution, such as the emergence 

 of air-breathing forms, are likely to have been paralleled at the earUer biochemical 

 stages at such jumps as the genesis of sugars, nucleic acids and fats. One of our 

 major problems is to establish the correct order of the steps inferred from existing 

 metabohsm as well as the postulating and checking of other steps which have 

 been subsequently effaced by the success of more efficient biochemical mecha- 

 nisms. 



Before considering these transitions in detail I would like to recall certain 

 general principles which may serve to guide the lines of speculation without 

 themselves furnishing decisive arguments for or against any particular solution. 

 The first of these is the principle of Lyell which tells us to search in the present 

 world for processes which may have occurred in the past. In its particular 



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