The minimum requirements for the evolution of a cell

| March 22, 2015 | 0 Comments

P M BHARGAVA

Published in: Experimental Cell Research, 1962, 27, 453-467.

Abstract:

The objective of this presentation is to focus attention on certain issues that intimately relate to the question of the origin of life on our planet, but have not been so far adequately considered.

Most scientists would agree that chemical evolution has occurred on our planet after its formation some 4.5 billion years ago. During this evolution, increasingly comp 1 ex substances (including polyribonucleotides and polypeptides), in increasing variety, were formed as time progressed, from the simpler chemical constituents of Earth’s primordial atmosphere, aided by climatic and geological changes. The evidence for this comes from laboratory experiments simulating conditions that are likely to have been prevalent in the Earth’s earliest atmosphere, and from the analysis of carbon-containing compounds in meteorites, comets and interstellar space. It seems most likely that chemical evolution would be an inevitable outcome on any planet on which conditions similar to those on Earth when it was formed, would exist.

Similarly, there is little doubt that, subsequently, Darwinian biological evolution has occurred on our planet, leading to speciation; morphological and molecular biological evidence for such evolution, today, is overwhelming. The Darwinian biological evolution could, obviously, have operated only on cellular systems. There is evidence of fossil cells dating back to some 3.5 billion years ago.

We, therefore, do not yet understand how the transition from the chemical to the biological evolution occurred, that is, how the first cell (on which Darwinian biological evolution could operate) was formed from the “end-products” of chemical evolution. The missing link between the chemical and the biological evolution is, today, one of the most important lacunae in our understanding of the origin of life on our planet.

It is clear that we cannot find the missing link unless we define what we are trying to link together – that is, what we are wishing to arrive at, and from what. In other words, we must be able to make an intelligent guess about the end-products of the chemical evolution and the criteria that the first cell must have satisfied. It is only then that we can look at the various possibilities of arriving at the first cell from the end-products of the chemical evolution.

HOW TO CITE

The minimum requirements for the evolution of a cell. P M BHARGAVA. Advances in Space Research, 1986, 6, 7-11.

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