Chapter 9: Evolution, genetic memory, variation and selection

Synopsis

The theory of evolution provides us a simple and comprehensive picture of the origin of the enormous variety of life on Earth. It begins with our first universal common ancestor. The origin of this creature remains mysterious although we know that all the ingredients for life were in place: the solar system and the planet Earth with sunlight and chemical conditions suitable for life. At this point the Universe had already been evolving for about 9 billion years. For the very early period the best we can say is that the elementary particles we know of crystallized out of the enormous conflagration of the big bang as it cooled. My hope in this book is to construct a more epistemologically oriented account exploiting the logical computational power of quantum mechanics.

9.1: Where did all these species come from?

9.2: From eternity to evolution

9.3: Genes and living memory

9.4: Variation

9.5: Selection

9.6: Evolution prior to life?

9.7: Sexual selection

9.1: Where did all these species come from?

Where did we come from? Our ancestors. And where did they come from? . . . There are just two answers. The structure of time demands that ancestors have always existed or they came to be sometime in the past. And if they were created, where did the Creator come from? Ultimately, if we stand by the proposition that nothing comes from nothing, we are led to propose that either the world or its creator is eternal.

Traditional creation stories are generally quite simple and straightforward. The Christian story, taken from the Hebrew book Genesis, is repeated twice in a few pages. They just knew that a creator (God in English) had made the things they could see, light, sky, water, land, plants, animals and people.

In the Roman Catholic interpretation of this story, the omniscient divinity carefully planned the world and used their omnipotent words, let there be (Latin fiat), to bring it into existence. The Catholic Church, through the first Vatican Council, holds that the world was created from nothing:

This one, true God, of his own goodness and "almighty power", not for increasing his own beatitude, nor for attaining his perfection, but in order to manifest this perfection through the benefits which he bestows on creatures, with absolute freedom of counsel "and from the beginning of time, made out of nothing both orders of creatures, the spiritual and the corporeal. . . . Catholic Catechism, § 293: III. "The world was created for the glory of God"

Darwin caused the biggest shock in the scientific world since the medieval European recovery of Aristotle. The old story of six days of creation was replaced with fourteen billion years of evolution in a Universe capable of creating itself. How this might work, beginning from an initial singularity formally identical to the traditional Catholic god, is the subject of this book.

I understand that Universe evolves under its own omnipotent creative power because it is divine. We still do not know in detail how life began, but it did. The last universal common ancestor is the biological analogue of the initial singularity. All life on Earth embodies molecular mechanisms related by descent from this common source. Last universal common ancestor - Wikipedia

On The Origin of Species draws on many lines of evidence. Darwin’s key idea was not just evolution, which had occurred to many people before him, but the way it happens, by variation, memory and selection. He began his book with the evidence closest to hand, the work of breeders of domesticated plants and animals. This showed that species were not fixed from eternity by the creator. In its time, this was perhaps Darwin's most radical idea.

Many changes in domesticated plants and animals may have been accidental, planting seeds from the best looking plants for example. Later we learnt to choose breeding stock with a particular end in mind: finer wool or sweeter apples. This caused a radical revision of the ancient idea of creation. God did not create the world and all its forms of life in a few days. Creation is a very slow process, taking places everywhere there is life.

Many still do not believe that we too are a product of evolution. The Roman Catholic Church rejects the idea that we could have evolved:

. . . theories of evolution which, in accordance with the philosophies inspiring them, consider the mind as emerging from the forces of living matter, or as a mere epiphenomenon of this matter, are incompatible with the truth about man. Nor are they able to ground the dignity of the person. Pope John Paul II (22 October 1996): Address to Plenary Session on 'The Origins and Early Evolution of Life'

By denying that evolution can ground the dignity of the person, John Paul II is also denying the dignity of the Universe. As we go along we will see that we are the created image of the intelligent divine Universe.

9.2: From eternity to evolution

Darwin made the case for evolution among living creatures. He knew from geology that some of the geological formations in Britain are hundreds of millions of years old. There was plenty of time available for the gradual evolution of species. We now estimate that life began about four billion years ago. We have fossil evidence of single celled creatures more that three billion years old.

The Sun was formed about 4.5 billion years ago, and Earth soon after. The age of the Universe since the initial singularity is 14.8 billion years. The conditions that created the solar system had already been evolving for ten billion years.

The theory of evolution has a central role in biology. A question here is: can the evolutionary paradigm be applied prior to the origin of life? Can it account for the differentiation of the initial singularity into the present Universe.

9.3: Genes and living memory

Every living creature carries two copies of itself, one a formal abstract representation encoded in DNA, the other its full physical reality. Darwin did not know this. He did know that children share many traits with their parents and are often very different. Variation made it possible for people who fancied particular traits in their plants and animals to control breeding to get a particular phenotype. The wolves that were bred into dogs now range in size from rabbits to small cattle.

Darwin proposed that nature itself practised selective breeding. He saw that natural selection is simply a consequence of the fact that some individual variations are better able to thrive and reproduce in particular environments. Varying species can track the variations of changing environments. If species cannot keep up with the rate of change they become extinct. If the environment splits into two, a species may also split, creating new species. Over billions of years since life began it has shaped its own environment including changes in species themselves and their relationships to one another. Our own origin in the last few hundred thousand years and our recent exponential growth is causing massive environmental change and extinctions on Earth right now.

Darwin was able to formulate his hypothesis without any specific knowledge of genetics. Gregor Mendel (1822-1884) carefully counted variations in the traits of peas from different matings and correlated these variations across generations.

He found that some traits are transmitted from parents to offspring in fixed ratios. This points to a discrete mechanism governing inheritance. Mendel published his work in 1865, but it took fifty years for his discoveries to be appreciated. Mendel knew and was pleased by Darwin's work. Darwin knew nothing of Mendel.

Gradually through the last century the genetic mechanisms of inheritance have been a elucidated in increasing detail. A multinational project to sequence the whole human genome began in 1990 and was partially complete in 2003.

Since then gene sequencing has become a common laboratory procedure. It is often used for medical and forensic studies to establish the genetic foundations of disease, to establish human relationships and to identify people who may have been present at crime scenes and those found dead.

While the function of genetics in biology is now well understood, it remains an open question whether analogous processes can be invoked to explain the development of Universe from the initial singularity to the origin of life.

9.4: Variation

Random variation is the first requirement for creative evolution. The sources of this variation are to be found deep in the biological mechanisms of reproduction. One measure of evolutionary variation in an organism is the probability of a change (a mutation) in the elements of its genetic code. The probability that a mutation is deleterious or fatal is generally far greater than the probability that it will provide an advantage, but this disadvantage is outweighed by the fact that reproduction is a form of exponential chain reaction.

Sexual reproduction works both for and against variation. By mingling the genes of two individuals, it provides a path to increased variation. It also increases the possibilities for error correction since the genes of two individuals of the same species are quite similar. One set may be used to correct the other. They key to variation and probability is lack of control, discussed in Chapter 8: God's ideas, cybernetics and singularity.

9.5: Selection

Randomness is the key to variation. Selection, on the other hand, depends on knowledge and control. Creatures use both the information embedded in their genes and what they have learnt since birth to survive and reproduce. This is particularly important in our own survival, which depends on the collective memory embedded in our cultures. We have an enormous body of permanent information embedded in art, literature and industrial knowhow. Much of this exists as physical capital, the structure of our cities, factories, machines and consumer goods.

Success in life, which in evolution means successful reproduction, depends heavily on chance, but also on the ability of each organism to take advantages of the chances as they present themselves.

Selective pressure is primarily a function of environment. This may occur at many scales ranging from geology and climate to politics and culture. Political organizations like the Catholic Church and other religions direct the course of cultural evolution by restraining some directions and encouraging others.

Repressive regimes control the cultural selective environment by coercive education, imprisonment, torture and murder. These attacks are directed particularly at women to maintain masculine supremacy. The Roman Catholic Church steadfastly resists admitting women to have priestly roles. We might suspect that this has something to do with the ubiquity of clerical abuse of children which is gradually coming to light. Pope Paul VI: Inter Insigniores: On the question of admission of women to the ministerial priesthood (15 October 1976)

9.6: Evolution prior to life?

The big bang hypothesis imagines that the explosion of the initial singularity is enormously energetic at a very high temperature. Our experience with high energy particle accelerators shows us that we can produce large numbers of well known particles by colliding massive bubbles of almost pure energy. This suggests that very fast processes can build a spectrum of particles from a structure very close to the initial singularity.

Our current understanding of the nature of these particles is the Standard Model, represented by a large body of literature, This has grown steadily, overcoming many problems, since Planck's discovery of the quantum of action. It is not easy to reconcile quantum mechanics with special relativity nor is there any satisfactory connection between gravitation and quantum mechanics. Standard model - Wikipedia

All the fundamental particles that we know, regardless of their lifetimes, have very specific properties, not subject to evolution. To the best of our knowledge, these particles have not changed their properties over the life of the Universe. It is only when we come to large molecules that we see evolution, usually in the context of some form of life.

9.7: Sexual selection

Darwin noticed that many traits, like the plumage and musicality of birds and the enormous variety of colours, scents, sizes and shapes of flowers appear to be favoured in selection without much immediate apparent advantage as resources for survival.

The female role in sexual reproduction limits their choice of mates, since they can only produce a limited number of children per reproductive cycle. Female choice may therefore induce males to develop certain specific characteristics which are attractive to females. If these characteristics actually work, whatever they may be, they will be propagated by reproductive success. Flowers and peacocks’ tails exist because they work.

This may lead to a positive feedback loop. Both the male and female offspring of the females who choose a particular class of male will inherit the genes associated with that class. This may encourage more females to choose this class of male. Ronald Fisher studied this feedback and gave it a statistical basis which is called the Fisherian runaway. Fisherian runaway - Wikipedia

Geoffrey Miller feels that evolution may explain why our ancestors became attracted not only to pretty faces and healthy bodies, but to minds that were witty, articulate, generous and conscious. There is more to being good in bed than sex. The enormous creativity of evolution arises from its random input. Geoffrey Miller: Sexual selection for indicators of intelligence

Bush flies are an irritating nuisance in Australia, almost impossible to hit. They owe their agility to their amazing eyes and to their halteres, a form of gyroscope. To get these organs they sacrificed a pair of wings and so gained the selective advantage of a local quasi gyroscopic reference to orientate themselves in space. No doubt this feature will ultimately be added to fighter planes. Gyroscopes are commonly used for attitude control in spacecraft. Halteres - Wikipedia