Life Evolving: Molecules, Mind, and Meaning
by Christian de Duve

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Book Reviews of Life Evolving: Molecules, Mind, and Meaning

Book Review: Interesting and thought provoking book
Summary: 4 Stars

De Duve gives a great review of just how cells work at the molecular level. There is adequate depth without getting bogged down in details. What I really wanted to see was his explanation for the origin of life. De Duve proposes that

Abundant triphosphates somehow arose to provide energy
Prebiotic peptide catalysts somehow arose
Myriads of different RNA-like molecules somehow formed from phosphates
"Rare true-RNA" molecules evolved by Darwinian evolution
RNAs began to make proteins out of the abundant amino acid soup
The RNAs began to make cell walls
The genetic code for specific proteins arose via Darwinian evolution
These very short RNA chains grew tremendously longer via Darwinian evolution
DNA developed from RNA to form protocells
The protocells evolved via Darwinian evolution until they became the first living cells

The key to his proposal is molecular selection. "This mechanism, it must be emphasized, represents at the molecular level exactly that imagined by Darwin to account for biological evolution". In other words, the way to get around the incredible odds of accomplishing each of the proposed steps to life listed above is by having non-living molecules competing with each other. The winning molecules then advance to the next level of competition.

De Duve is rather less than kind to those who disagree. He is distressed that many intelligent people, even scientists, do not agree that this is a plausible explanation to the origin of life. As one with a background in the earth sciences, I am one of the skeptics. My major problem is that he seemingly ignores data from other scientific disciplines. His premise depends on assumptions that are either wrong or improbable at best.

His proposal requires a benign chemical environment with a rich prebiotic soup from which the peptides, RNAs, and proteins could form. Geochemists and planetary physicists have conclusively demonstrated that this soup simply didn't exist. The neutral atmosphere of the early earth could not form prebiotics. In addition, there was sufficient photogenic oxygen in the atmosphere and radiogenic (radiation-induced) oxygen in the oceans to destroy them if they did form. No "prebiotic soup" has ever been found, although "post-biotics" are extremely common. What does exist in abundance are deposits of poisonous heavy metals and rare-earth elements. The early ocean more closely resembled the deadly effluent from a toxic waste dump than the prebiotic soup De Duve needs. Entire industries exist to mine these materials which were once poisons dissolved in the early oceans.

De Duve proposes that prebiotic materials were delivered to the Earth from outer space. Small amounts of nucleic acids have been found in some meteorites, and comets often contain some carbon compounds as well. In reality, the volume of chemicals is small, but the energy release is not. For example, the Shoemaker-Levy comet which struck Jupiter in 1994, probably contained hundreds of tons of organic compounds. This is the proverbial "drop in a bucket" in terms of getting a meaningful volume of prebiotics into the ocean. However, the impact event was roughly 100 million megatons of TNT. This is ten thousand times the power of all of mankind's nuclear weapons combined. We would all be dead if this impact had occurred on Earth.

Another problem occurs in obtaining concentrated baths of organic compounds. The scenarios De Duve mentions are Darwin's "warm little pond" and Stanley Miller's "drying lagoon". These are physical impossibilities on the early earth, where tides were measured in hundreds of feet and wind speeds were measured in thousands of miles an hour. Think of the movie "Perfect Storm" and consider that the weather never got that nice 3.9 billion years ago! There is no plausible mechanism available to generate a concentrated bath of prebiotic compounds in such an environment.

The last several chapters delve into esoteric astronomical subjects far from De Duve's area of expertise, including life on other planets. Large numbers are quoted, but there is little discussed in the vein of cause-and-effect from which a meaningful statistical calculation could be made. He acknowledges that the physical properties of the universe exhibit evidence of incredible precision which allows life to exist. Inconceivably tiny deviations in a number of parameters would make life impossible. This "anthropic principle" has led many formerly atheistic or agnostic scientists to a belief in God. I know one radio-astronomer who wrote "Astronomers who do not draw theistic or deistic conclusions are becoming rare", while his atheist collegue complained that his fellow astronomers are rushing off to join "the First Church of Christ of the Big Bang." De Duve apparently prefers the explanation that there are an infinite number of universes, perhaps even evolving via natural selection, and ours is the lucky one.

De Duve's final appeal is that "something positive must be proposed that can eventually replace the myths propagated by religion." God does not exist, but we need "spiritual guides" to provide ethics and morals. "The religious feeling is deeply embedded in our nature, probably carved into it by natural selection"

I enjoyed De Duve's excellent description of cellular biology. However, I found his proposed mechanisms for the origin of life unconvincing and unsupported by actual chemical pathways. He ignored the hard evidence from other scientific disciplines that render his explanations highly implausible. His premise that science has demonstrated naturalistic explanations to how the universe, the earth, and mankind got here requires more faith than I can muster. I remain skeptical, and tend to agree with the astronomers, who are finding increasing evidence of "something else behind it all".

Summary of Life Evolving: Molecules, Mind, and Meaning

Biology Books

• Subjects > Science & Math > Biological Sciences > Biology
• Evolution
• History & Philosophy