2. The origin of life
Most scientists believe that the emergence of life began with the chance formation of the first self-replicating molecule in a prebiotic soup rich in organic compounds, amino acids and nucleotides. Then, driven by natural selection, ever more efficient and complex self-reproducing molecular systems evolved until finally the first simple living cell emerged.However, the earliest rocks fail to provide any evidence that a prebiotic soup ever existed, and the original assumption that the earth’s early atmosphere was a favourable mixture of ammonia, methane and hydrogen and contained no free oxygen has also been called into doubt. Instead, it is now widely believed to have been a mixture of carbon dioxide, carbon monoxide, nitrogen and water vapour, and to have included significant amounts of free oxygen. Such atmospheric conditions would have hampered the production of amino acids and other molecules necessary for life, and broken down any organic molecules that did form.1
All modern life forms contain genes made of DNA (deoxyribonucleic acid), which contains nucleobases, whose sequence encodes instructions for making proteins. However, DNA is unable to manufacture proteins by itself. Protein synthesis requires ribonucleic acid (RNA) and a tightly integrated sequence of reactions, involving over a hundred different proteins (including enzymes, which catalyze chemical reactions). This poses a chicken-and-egg problem: which came first, nucleic acids or proteins?
Fig. 2.1. DNA has the form of a double helix, a spiral consisting of two DNA strands wound around each other. Each strand is composed of a long chain of nucleotides. Each nucleotide consists of a deoxyribose sugar molecule to which is attached a phosphate and one of four nucleobases: adenine (A), guanine (G), cytosine (C), and thymine (T). The two DNA strands are held together by the hydrogen bonds between pairs of bases; A only bonds with T, and C with G. Segments of DNA that code for the cell’s synthesis of a specific protein are called genes, which are packaged into threadlike structures called chromosomes. When a cell divides, its DNA replicates by separating into two single strands, each of which serves as a template for a new strand.
Fig. 2.2. Highly simplified diagram of protein synthesis (or gene expression). During transcription, the sequence of nucleobases on a strand of DNA is reproduced on a molecule called messenger RNA (mRNA) by an enzyme known as RNA polymerase. Next, mRNA migrates from the cell nucleus to a structure called a ribosome in the cytoplasm, where a process known as translation takes place. With the help of transfer RNAs (tRNAs) and specific enzymes, a chain of amino acids is built up, with each amino acid being specified by a three-nucleotide sequence (a codon) on the mRNA. The amino-acid chains then fold into functional proteins. The full complexity of protein synthesis is staggering (see animation).
RNA is less complex, but also less stable, than DNA, and uses the same chemical alphabet, except that uracil is substituted for thymine. Many biologists believe that early in the earth’s history there was an ‘RNA world’, which eventually developed into the DNA, RNA and protein world of today. It was thought that this would solve the chicken-and-egg problem, because as well as being able to store information, certain RNA molecules possess some of the catalytic properties of proteins. But the theory does not solve the problem of the origin of RNA. Synthesizing and maintaining RNA constituents, particularly ribose (a sugar) and the nucleobases, have proven either extremely difficult or impossible under realistic prebiotic conditions.2 Various additional hypotheses have been proposed – e.g. that life originated in deep oceanic hydrothermal vents, or on the surface of clay or iron pyrite (fool’s gold) – but none provides a convincing explanation for the origin of the cell’s genetic code and information-processing system. Some scientists have suggested that the first living organisms might have been carried to earth from other planets (e.g. Mars) or outer space – but this merely moves the problem elsewhere.
Each of the 60 trillion cells in the human body contains a 2-metre-long string of DNA coiled into a tiny ball about 5 thousandths of a millimetre in diameter in the cell nucleus. The information storage density of DNA is many times that of our most advanced silicon chips.3 DNA can store information on protein synthesis so efficiently that all the information needed for an organism as complex as a human weighs less than a few trillionths of a gram. Geneticist Michael Denton remarks:
To the sceptic, the proposition that the genetic programmes of higher organisms, consisting of something close to a thousand million bits of information, equivalent to the sequence of letters in a small library of one thousand volumes, ... were composed by a purely random process is an affront to reason.4Physicist Paul Davies has said that ‘the spontaneous generation of life by random molecular shuffling is a ludicrously improbable event’.5 Douglas Axe calculated that the probability of producing a functional protein of modest length (150 amino acids) at random is only about 1 in 1074 (i.e. 1 followed by 74 zeroes). Moreover, chains of amino acids will only fold into a protein if they are joined by a chemical bond known as a peptide bond – with a probability of 1 in 1045. There are thousands of kinds of amino acid, but living organisms contain only 20 kinds, and although amino-acid molecules occur in both right- and left-handed forms, only left-handed amino acids are found in the protein of living organisms – the probability of this is also about 1 in 1045. This means that the odds of producing even one functional protein of modest length by chance from a prebiotic soup is no better than 1 in 10164. If we assume that a minimally complex cell needs at least 250 proteins of, on average, 150 amino acids, the probability of a living cell arising by chance is just 1 in 1041,000 – an unimaginably small number.6Astrophysicist Fred Hoyle concluded that the probability of even the simplest known life form arising by accident was ‘evidently nonsense of a high order’, and ‘comparable to the probability that a tornado sweeping through an airplane junkyard would happen to assemble a flyable Boeing 747’.7
Even if proto-cell systems were to emerge, they would be far more prone to making translational errors when synthesizing proteins and it is difficult to see how they could be viable. In the words of evolutionary biologist Carl Woese: ‘The primitive cell was faced with the seeming paradox that in order to develop a more accurate translational apparatus it had first to translate more accurately.’ And Denton adds:
That such a cell might undergo further evolution, improving itself by ‘selecting’ advantageous changes which would be inevitably lost in the next cycle of replication, seems contradictory in the extreme. ... [A]n error-prone translational system would lead inevitably to self-destruction ...8Beginning with the Miller-Urey experiment in 1953, scientists have spent countless hours trying to create life in the laboratory, by passing sparks through favourable mixtures of gases (now considered to be unrepresentative of the early atmosphere), but all they have achieved is the production of certain prebiotic organic molecules, such as amino acids. The experiments have been described as ‘a story of abject scientific failure’, because any desirable molecules formed invariably react with unwanted by-products, resulting in ‘tar-like goo’.9 No nucleotides of any kind have ever been produced in spark-discharge experiments. In other types of experiments chemists have managed to engineer a partially self-replicating RNA molecule, but only by exercising great ingenuity and creating unrealistic conditions.10 The irony of this has not gone unnoticed:
We find ourselves in the situation in which the biochemist, with the exercise of much thought, care and purposive activity, together with the use of elaborate and intricate equipment, can duplicate in his laboratory a few of the simpler processes known to be performed at a considerably higher level of complexity by a single microscopic living cell – the activities of the cell being ascribed to hazard and chance!11
Fig. 2.3. There are two types of cells: prokaryotic cells contain no nucleus, while eukaryotic cells contain a nucleus and membrane-bound organelles such as mitochondria. Single-cell prokaryotic organisms are believed to have appeared about 3.8 billion years ago, and eukaryotic cells about 2 billion years ago. Eukaryotes include many unicellular organisms (e.g. protozoa) and all multicellular organisms (including plants, fungi, animals and humans).
A typical animal cell contains 10 million million atoms, and is a structure of breathtaking intricacy. If we were to magnify a cell a thousand million times until it was 20 km in diameter, we would see an object of unparalleled complexity resembling an immense automated factory, larger than a city and carrying out almost as many functions as all the manufacturing activities of humans on earth. Yet it is capable of replicating its entire structure within a matter of hours. Furthermore, experiments have shown that, far from moving at random, cells can respond intelligently to their environment as they possess a ‘control centre’ (a centrosphere, containing two centrioles) which is ‘capable of collecting and integrating a variety of physically different and unforeseeable signals as the basis of problem-solving decisions’.12
Fig. 2.4. A typical animal cell: 1. nucleolus; 2. nucleus; 3. ribosome (the dots); 4. vesicle; 5. rough endoplasmic reticulum; 6. Golgi apparatus; 7. cytoskeleton; 8. smooth endoplasmic reticulum; 9. mitochondrion; 10. vacuole; 11. cytosol; 12. lysosome; 13. centriole; 14. cell membrane.13
Geneticist Jacques Monod admitted that the origin of the genetic code and its translational mechanism was a ‘veritable enigma’, and Francis Crick, cowinner with James Watson of the Nobel prize for the discovery of the structure of DNA, said that the origin of life appeared to be ‘almost a miracle’.14 Chemist Robert Shapiro has said that both DNA and RNA are too complex to have arisen spontaneously, and hoped for the discovery of ‘some new natural principle’ to explain their origin.15 Even time travel – allowing engineers from the future to seed life in the present – has been seriously proposed by some physicists. Rodney Brooks suggested in Nature that scientists might be ‘missing something fundamental and currently unimagined’ in their models of biology, and that ‘some aspect of living systems is invisible to us right now’.16
Life is believed to have appeared on earth about 3.8 billion years ago, within just 10 or 20 million years of viable conditions arising. This led palaeontologist Stephen J. Gould to say that the origin of life on earth was ‘a chemical necessity’ and ‘virtually inevitable given the chemical composition of early oceans and atmospheres, and the physical principles of self-organizing systems’.17 Many other scientists have adopted the same tune. For instance, Nobel laureate Christian DeDuve has said that the emergence of life and mind are ‘written into the fabric of the universe’. Paul Davies believes that above a certain threshold of complexity, new-style ‘complexity laws’ come into action, enabling a system to ‘self-organize and self-complexify’, and this could rapidly direct a system towards life.18 However, ‘complexity laws’ and ‘self-organizing principles’ are just words; the forces and operations they denote have never been satisfactorily explained in physicochemical terms.
One suggestion is that simple chemicals might possess ‘self-ordering properties’ capable of organizing the constituents of proteins, DNA and RNA into the specific arrangements they now possess. But as Stephen Meyer explains, ‘biochemistry and molecular biology make clear that forces of attraction between the constituents in DNA, RNA, and proteins do not explain the sequence specificity of these large information-bearing biomolecules.’19 For instance, self-organizing bonding affinities cannot explain the specific arrangement of nucleobases in DNA because there are no chemical bonds between its nucleobases, and there are no differential affinities between the bases and the sugar-phosphate backbone, which means that any base can attach to the backbone at any site with equal ease.20 Physicochemical laws describe highly regular, ordered patterns, but lawlike processes cannot generate functional information, which is characterized by irregular complexity. Mind or intelligence is the only cause known to be capable of generating the complexity and information content found in DNA and RNA.
Information theorist Hubert Yockey held that the information needed to begin life could not have developed by chance, and suggested that life be considered a given, like matter or energy.21 Astronomer Erich Jantsch wrote: ‘Life no longer appears as a thin superstructure over a lifeless physical reality, but as an inherent principle of the dynamics of the universe.’22 Physicist David Bohm believed that life and consciousness were enfolded deep in the ‘implicate’ or ‘generative’ order underlying our physical (or ‘explicate’) world, and were therefore present in varying degrees of unfoldment in all matter, including ‘inanimate’ matter.23
The theosophic tradition, too, recognizes life and consciousness as the ultimate ground of the universe, and indeed the ultimate mysteries. Rather than dead physical matter miraculously giving rise to life and consciousness when it reaches a certain level of organizational complexity, consciousness-life-substance is seen as an eternal and universal unitary essence, manifesting in infinite degrees of density and in infinitely varied forms. Physical matter is a more condensed manifestation of the finer grades of consciousness-substance that make up the more ethereal realms, including the subtler elements of each organism’s own constitution. Life is therefore present in all of nature’s kingdoms, but in different degrees of development.
Scientists generally regard the cell as the smallest living unit. But they do not understand how ‘dead’ matter can suddenly become alive, or why the spontaneous generation of life seems impossible today. Death is also hard to explain: Why does organization as an entity suddenly cease, sometimes without any evident cause? After all, it is the same ‘inert’ matter which composes living and nonliving things. There is clearly something missing from the scientific picture: life cannot be reduced to physicochemical processes.
The advent of ‘living’ organisms undoubtedly represents a huge advance on the more latent forms of life to be found in the mineral kingdom.
A crystal may be said to feed and grow, but it feeds upon the same single substance of which it is made, and it grows by accretion, not by assimilation of selected portions of a mixture of foodstuffs and their chemical modification into protoplasm. A crystal may serve as a nucleus for the growth by accretion of a new crystal, but this is quite different from the division of the contents of the living cell, to form a replicate daughter-cell.24Theosophy sees the emergence of higher molecular and cellular forms of life as one of nature’s habits (‘laws’), an event that recurs in each major evolutionary cycle. But rather than physical matter organizing itself into organic forms, its activities are largely organized and coordinated from deeper levels of reality. The widely varying degrees of manifest life (and mind) displayed by the mineral, plant and animal worlds arise from the level of sophistication of the vehicle that the animating consciousness, or monad, has to work through, as this determines how much of its inner potential can be expressed. In more complex organisms, an increasing role is played by etheric life-currents (prana or chi) which circulate through the astral model-body, thereby helping to vitalize the physical body and sustain its electric life-field. Prana can be regarded as an individualized expression of jiva, the ocean of life in which we are all immersed.
- Stephen C. Meyer, Signature in the Cell: DNA and the evidence for intelligent design, New York: HarperOne, 2009, pp. 224-6; Simon Conway Morris, Life’s Solution: Inevitable humans in a lonely universe, New York: Cambridge University Press, 2003, pp. 61-2.
- Signature in the Cell, p. 301.
- Ibid., p. 97.
- Michael Denton, Evolution: A theory in crisis, Bethesda, MA: Adler & Adler, 1986, p. 351.
- Paul Davies, The Cosmic Blueprint, London: Unwin, 1989, p. 118.
- Signature in the Cell, pp. 210-3.
- Quoted in Alexander Mebane, Darwin’s Creation-Myth, Venice, FL: P&D Printing, 1994, p. 35.
- Evolution: A theory in crisis, pp. 266-7.
- Life’s Solution, pp. 37, 44.
- Signature in the Cell, pp. 302, 313-4, 334-5.
- Corona Trew and E. Lester Smith (eds.), This Dynamic Universe, Wheaton, IL: Theosophical Publishing House, 1983, p. 132.
- Guenter Albrecht-Buehler, ‘Cell intelligence’, basic.northwestern.edu. See Rudi Jansma, ‘Cosmic mind in the microcosm’,Sunrise, April/May 2004, pp. 118-26.
- Quoted in Evolution: A theory in crisis, p. 268.
- Darwin’s Creation-Myth, pp. 35-6.
- Rodney Brooks, ‘The relationship between matter and life’, Nature, v. 409, 2001, pp. 409-11.
- Stephen Jay Gould, Wonderful Life: The Burgess Shale and the nature of history, New York: Norton, 1989, pp. 289, 309.
- David P. Woetzel, ‘The spontaneous generation hypothesis’, Creation Research Society Quarterly, v. 38, no. 2, 2001, pp. 75-8.
- Michael J. Behe, William A. Dembski and Stephen C. Meyer, Science and Evidence for Design in the Universe, San Francisco, CA: Ignatius Press, 2000, p. 87.
- Signature in the Cell, pp. 240-9.
- ‘The spontaneous generation hypothesis’.
- Quoted in Anna F. Lemkow, The Wholeness Principle: Dynamics of unity within science, religion & society, Wheaton, IL: Quest, 1990, p. 137.
- David Bohm and F. David Peat, Science, Order & Creativity, London: Routledge, 1989, pp. 200-1.
- This Dynamic Universe, p. 131.
An article published by David Pratt. @ http://davidpratt.info/evod1.htm