Evolution theory
Chapter 1 - Worldview
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Welcome to the Evolution theory page
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Life as we know it today would be impossible without the processes described in Darwin's evolution theory.
Before Darwin, men assumed that a supernatural creator provided all kinds of life. We can hardly overestimate its revolutionary character.
However, organisms with traits better adapted to the circumstances can produce more offspring because those traits help them survive. Through (chance) variation and adaptation to changing external conditions, populations change because the genes of better-adapted individuals can spread more quickly in the population.
In 1973, biologist Theodosius Dobzhansky wrote: “Nothing in biology makes sense except in the light of evolution."
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Core idea
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Core of the evolution theory as constructed by Charles Darwin
The core message of the evolution theory is that all species of life on this earth have evolved slowly from a common ancestor organism thanks to the mechanism of natural selection.
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- Mutation
- somewhere in the population, ensures
- Variation
- in the relationship of individuals of the population regarding the context, creats possibilities for
- Selection
- of the most adapted individual regarding the context who is able to reproduce.
- Reproduction
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Only the third step of the evolutionary process is focused on the individual. Even in the case of selective survival, if the most adapted to the environment cannot reproduce, the new feature will only exist for a very short time in a very tiny place.
Darwin's theory is about 'the origin of species, not the origin of individuals'.
| Darwin online |
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| Darwin Online (darwin-online.org.uk) |
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A dangerous idea
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The core idea by Darwin himself
| On the Origin of Species BY MEANS OF NATURAL SELECTION - By Charles Darwin, M.A., F.R.S. - Sixth London Edition, with all Additions and Corrections. |
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| If under changing conditions of life organic beings present individual differences in almost every part of their structure, and this cannot be disputed; if there be, owing to their geometrical rate of increase, a severe struggle for life at some age, season or year, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of life, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, it would be a most extraordinary fact if no variations had ever occurred useful to each being’s own welfare, in the same manner as so many variations have occurred useful to man. But if variations useful to any organic being ever do occur, assuredly individuals thus characterised will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance, these will tend to produce offspring similarly characterised. This principle of preservation, or the survival of the fittest, I have called Natural Selection. |
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We are not the centre of the world
| D. Dennett – Darwin’s Dangerous Idea - Penguin Books - 1996 |
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| Both the emergence of adaptation and diversity were different aspects of one complex phenomenon, and the idea that links the two was, in his view, the principle of natural selection. |
Darwin's (evolution theory) most significant contribution to thought is his rejection of essentialism. This classical doctrine holds that for every natural thing or species, there is an essence, a necessary and sufficient set of properties that make something part of that species. Instead, he showed that species are historically linked by a chain of variations that differ so tiny that there is no reason to draw a line anywhere.
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| D. McMahon - Equality - Ithaka - 2024 |
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| Still in current days, social Darwinism, moves from the survival of the fittest WITHIN SPIECES, to the survival of the fittest BETWEEN people, business, organisations, … |
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Evolution selects for fitness, not truth
| The case against reality - D. Hoffman - Norton & Company - 2019 |
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| ... It’s all about struggles between genes. Which is to say, it’s all about fitness—the central concept of evolution by natural selection. Genes that are more adept at elbowing their way into the next generation are said to be fitter. Even a slight excess of talent in the art of the elbow can allow a gene to proliferate across generations and eradicate competitors of but moderate talent...
... We encounter a startling “Fitness-Beats-Truth” (FBT) theorem, which states that evolution by natural selection does not favor true perceptions—it routinely drives them to extinction... ... Our senses report fitness, and an error in this report could ruin your life. So our senses use “error-correcting codes” to detect and correct errors. Spacetime is just a format our senses use to report fitness payoffs and to correct errors in these reports... ... Only within that small window does your sensory interface construct a detailed report of fitness payoffs. That crucial report is formatted as the shape, color, texture, motion, and identity of a physical object.... |
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Deep dive
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Key take-aways from the deep dive
- Life occurs in the form of one of two 'major systems': self-organising or complex adaptive
- Forms of self-organising: plants, animals, humans, ...
- Forms of complex adaptive: nature, culture, ...
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Genes
The evolutionary process
Genes are passed on from parents to offspring, combining the genetic material of two organisms during sexual reproduction and ensuring that parents transmit their characteristics to their offspring.
Copying errors in transferring genes to offspring are not mistakes but rather the natural process that causes variation. Without these copying errors, life on earth today would still consist of the first single-celled bacteria, which emerged in the ocean about four billion years ago.
There is no evolution without
- variation because organisms do not change over time
- heredity because there is no selection, and beneficial variations are not passed on to offspring
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Competition to reproduce
Evolutionary competition to reproduce takes place not so much between organisms themselves as between genes.
They 'compete' to get as many copies of themselves into the next generation of organisms as possible. Of course, they don't do that consciously. They are blind, mechanical replicators. When the organisms they create and inhabit reproduce, they make copies of themselves.
Genes control organisms—they determine their physical and mental properties and, therefore, their behaviour. Genes use them to make as many copies of themselves as possible for the next generation, which has significant consequences for us, the organisms.
Every corner is fraught with peril, and the competition for scarce resources and reproductive opportunities is fierce. Only those genes that can adeptly equip and control their 'vehicles' will emerge victorious in this high-stakes competition for survival.
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How do they accomplish this?
Remarkably, the best way to succeed is to grant the organisms they inhabit a certain degree of freedom. Only then can the organisms tackle the dangers of the environment and the context.A particularly ingenious strategy for the gene to successfully guide their vehicle through an often hostile environment and to reproduce ensures that the organism responds appropriately to threats and opportunities. The organism responds appropriately to threats through intense sensations of pain or fear. Cravings or desires drive organisms towards food or reproduction.
- When an organism's action is beneficial to its survival or reproduction, it is rewarded with 'pleasure sensations'
- When an action is detrimental to its survival or reproduction, it is punished with 'pain sensations'
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- Men are attracted to slim women
- Overweight and obesity affect fertility by preventing ovulation.
- Women want taller men more than men want shorter women
- Women prefer, on average, a larger height difference between themselves and their partner (i.e. males being much taller than themselves) than men do.)
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Systems biology
Knowledge of the fundamental element of life (genes) does not yet give us insight into how life really works.
| A Systems Biological Interpretation of the Concept of No-Self (anātman) - Denis Noble |
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| Systems Biology is the study of the interactions between the elements (genes, proteins and other molecules) of living systems. Genes do not act in isolation either from each other or from the environment, and so I replace the metaphor of the selfish gene with metaphors that emphasize the processes involved rather than the molecular biological components. This may seem a simple shift of viewpoint. In fact it is revolutionary. Nothing remains the same. There is no ‘book of life’, nor are there ‘genetic programs’. The consequences for the study of the brain and the nature of the self are profound. They lead naturally to the concept of an tman, no-self, and to a better understanding of the relation between the microscopic and macroscopic views of the world. Organisms are viewed as variable open systems, rather than as determinate closed systems.Twentieth century biology was characterized by the identification and characterization of the molecular components of living systems: their proteins, genes and other molecules, such as lipids and metabolites. Almost as an extension of this approach it was assumed by many that the higher functions, such as consciousness, the will, the self, would also eventually be identified as objects, in particular as parts of the brain, or the workings of those parts. I believe that this was a profound mistake and that the biology of the 21st century, which is a systems approach, is set to correct this mistake. For this to be true, though, it is important to note that systems biology is not just a ‘next step’ development of molecular biology, as many of my scientific colleagues may think. It represents a profound revolution. The philosophy of systems biology is completely different from that of molecular biology (Kohl et al., 2010; Noble, 2010). To use a musical analogy, if molecular biology is the identification of the notes in a score, then systems biology is the music itself. If the molecular components are compared to the instruments of an orchestra, or the pipes of a cathedral organ, then systems biology is the performance. Whichever musical metaphor one might prefer (and I use several in my book, The Music of Life (Noble, 2006), each highlighting a different aspect of the difference between molecular and systems biology) the microscopic alone, i.e. the identification of the smallest components, is not sufficient to characterize its function. Even the concept of a gene as a DNA sequence is in serious difficulty (Beurton et al., 2008) as a consequence of recent discoveries in the field of epigenetics. We need a systems approach even to assess what a gene is (Noble, 2008b). Beurton et al. go so far as to say that a gene “begins to look like hardly definable temporary products of a cell’s physiology”.
Biological functionality is multi-level From the reductionist viewpoint, the causal chain runs upwards. It is a ‘one-way’ system, from the genes to the organism. The idea is that, if we knew all about the lowest level elements, genes and proteins, then everything about the organism would be clear to us. The second principle is the existence of downward causation. Downward causation exists between all the levels between which there are feedbacks. Events at higher levels can trigger cell signaling, all the levels are involved in the control of gene expression, it is protein machinery that reads genes to ensure their expression, and all levels can determine epigenetic marking. This marking is very important. It consists of another level of information and control superimposed on the DNA: a kind of chemical pattern carried by the DNA and which differs according to the cell type. It is this marking that ensures the correct gene expression patterns are transmitted from generation to generation in the tissues of the body in multicellular organisms. |
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Exaptation
Description
Exaptation is a term that comes from biology and was first used in 1982 in an article by Stephen Jay Gould and Elisabeth Vrba entitled: “Exaptation — a missing term in the science of form”. It refers to a characteristic of an organism that originally evolved as a trait that provides adaptation to certain conditions, and once it’s consolidated it begins to be used for another purpose, most of the time not related at all to its original purpose.
As an example: the feathers of birds, originated by the branching of the body “hairs” (protofeathers) of theropod dinosaurs as means to maintain body temperature, then they became key in flight.
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Exaptation as innovation
One way to approach innovation could be to analyse and look at all the assets of a company, institution or government, and innovate by giving them a different purpose than they originally had.
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Structures in nature and human systems
Life occurs in the form of one of two 'major systems'.
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Self-organising (dissipative) structures
Dissipative structures are open systems and they need a continual input of free energy (or exergy in nonisothermal case) from the environment in order to maintain the capacity to do “work.”
| E. B. P. Tiezzi, R. M. Pulselli, N. Marchettini & E. Tiezz - Dissipative structures in nature and human systems |
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| A Dissipative Structure is a thermodynamically open system operating far from thermodynamic equilibrium, that exchanges energy, matter, and information with the external environment. In this kind of systems, organization can emerge through a spontaneous self-organization process, by virtue of the exchanges with the external environment, that generates a formation of both spatial and temporal ordered structures, in which interacting constituents show long-range correlations.
The creation of spatiotemporal structures is extremely interesting because it causes macroscopic self-organisation that depends on microscopic interaction between organic and inorganic elements in the system. Order is created from an initial state of uniformity and chaos. |
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Complex adaptive systems
A complex adaptive system is a dynamic network of interactions. The behaviour of the ensemble may not be predictable according to the behaviour of the components. It is adaptive in that the individual and collective behaviour mutate and self-organise, corresponding to the change-initiating micro-event or collection of events. It is formed to adapt to the changing environment and increase its survivability as a macro-structure. The Complex Adaptive Systems approach builds on replicator dynamics.
| E. B. P. Tiezzi, R. M. Pulselli, N. Marchettini & E. Tiezz - Dissipative structures in nature and human systems |
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| Interactions between system constituents, that are neither isolated nor free, involve continuous reciprocal adaptation; each individual acts and reacts according to actions and reactions of the other individuals. This process, generated by competition and cooperation among the components, each pursuing its own aims, does not stop until organization that guarantees harmonious, non conflicting interactions among individuals is achieved. |
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Cultural Transmission
Culture represents a collection of attitudes, values, beliefs, and behavioral scripts that are generally agreed upon by a group of individuals. It can include everything from language, marriage practices, and governmental configurations, to definitions of family, greeting behaviors, housing structures, and death rituals, to name a few. A primary role of culture is to provide a consistent and stable environment or framework whose goal is to ensure or, at the very least, enhance, the survival of the group. At its broadest level, culture represents mainstream tendencies, but there can be “culture within a culture”.
| Content source |
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| Encyclopedia of Child Behavior and Development - 2011 |
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