A Planck Era in Biology?

Laws of physics control most of how the universe operates. These laws are believed to have come into being very soon after the Big Bang—specifically, a Planck time (approximately 10^-43 seconds) after the Big Bang)—and it is generally agreed that we can know nothing about what happened before that moment.

In biology, we don’t have mathematical laws with the precision and certainty that we have in physics, but enough is known to be confident that biology is a natural science and is therefore governed by laws, even if they have not been elucidated to the same extent as has been done for the non-living world. Among those laws is the theory of evolution by natural selection, which is not yet complete, but it has passed all tests and remains the bedrock of biological theory.

When combined with modern knowledge of genetics, physiology, and cell biology, the theory of evolution helps to guide us in understanding the great majority of biological questions and previously unsolved mysteries of life.

As the universe, life has a history. Science can look back in time to before there were human beings, before there were primates, or mammals, or vertebrates, all the way to the time when the only living creatures on the planet were single cells. And although as we go further back, we become less sure of what we know, we do know that the basic principles of biological science, including biochemistry and evolution, still hold.

But like the Big Bang that started physical reality as we know it, there was a beginning to life as well, and it was at some point before the existence of the most primitive living cell we can imagine. We call this hypothetical creature LUCA, which stands for the Last Universal Common Ancestor, since such a cell contained all the components required for life, and from this cell all further life could evolve by the processes we understand.

We can postulate that LUCA emerged in some way from protolife, but up to now, we have no clear path to understand anything about that emergence. It is my contention that such understanding of the origin of life before LUCA is, analogous to the time before the Planck era, impossible.

To continue the analogy: before LUCA, the laws of biology as we know them today did not exist; in particular, I maintain that the mechanism of evolution by natural selection was impossible. Since there is general agreement that LUCA could not have appeared spontaneously from chemical components, and therefore it must have evolved, we are left with the conundrum that we must have an evolutionary process before such a process was possible.

The only alternative is to postulate an alternative evolutionary process that does not rely on selection or on accurate replication. There is no theory that allows for the evolution, meaning the gradual change over many generations of a population of cells, that does not require high accuracy in replication of the cellular phenotype from one generation to the next. If a cell is able to improve in any way (energy usage, metabolic efficiency, longer life, more mobility, better biochemical reactions, etc.), but that improvement dies when the cell does and is not inherited by the daughter cells, the improvement is simply lost. Consider the following mathematical statement of gain of fitness (F) from generation n-1 to generation n due to selective advantage (S):

Fn = S(Fn-1)

Without accurate replication, this equation fails, since there is no relationship between Fn and Fn-1. Fisher’s fundamental theorem of natural selection, postulating an increase in fitness with time, would not hold.

The eminent pioneer of evolutionary biology and abiogenesis Eugene Koonin published a paper entitled “The Biological Big Bang Model for the Major Transitions in Evolution” that explores similar ideas, except that Koonin proposes a way to fill some of the gaps in biological evolutionary theory, postulating several Big Bang-like events. Koonin uses the expansion model from cosmology but he does not apply his model to the origin of life, nor does he suggest an analogy to the Planck era in cosmology.

It is my belief that just as in the origin of the universe, the origin of life will require new paradigms (including, perhaps, those now considered to be outside the boundaries of naturalism) to be understood.

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3 Responses to A Planck Era in Biology?

  1. dgilmanjm says:

    You and I disagree on this: “[evolution] has passed all tests”. I used to believe in evolution until it started to fail tests. But I’m not going to go into a debate on it.

    The other disagreement is the idea of “LUCA”. You and I debated this on Gather, and after that I read Carl Woese’s paper about the three domains of life having developed separately. Woese proposed that they each developed independently from a pool, so I am puzzled that he did not call for the abandonment of the LUCA belief.

    • That’s because the idea of LUCA is that it preceded all three of the domains that arose from it. Remember LUCA is only hypothetical, assuming that all life comes from a common ancestor. The three domains have major differences, but they share common genetic code and protein synthesis machinery and many enzymes.

      • dgilmanjm says:

        I was expecting that response, however, it is unrealistic to expect that one unit would have existed long enough to produce other units. What Carl Woese wrote suggest that it is more reasonable to say that several units enclosed short DNA (or RNA) strings, then interacted spontaneously with each other, mixing nucleic acids, then spontaneously divided, producing units with sequences and strings different from each other, eventually forming the hypothetical pool.

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