The "Theory" of
As Fact Not Fallacy
|The disingenuous take advantage of confusion, so still, after over 150 years,
Darwin's Theory of Evolution is very misunderstood by the public.
One thing that seems to trip up people's thinking is the meaning of the word "theory".
As in it's only a theory... So let's start by making this point clear.
There are 2 main definitions of theory, but unfortunately they kind of mean opposite things.
Definitions of Theory
(thee-uh-ree, theer-ee)1. A coherent group of tested general propositions, commonly regarded as correct, that can be used as principles of explanation and prediction for a class of phenomena: Einstein's theory of relativity.
noun, plural the·o·ries.
Synonyms: principle, law, doctrine.
|Theory in Use|
In technical or scientific use, Theory, principle, and law represent established, evidence-based explanations accounting for currently known facts or phenomena or for historically verified experience: the theory of relativity, the germ theory of disease, the law of supply and demand, the principle of conservation of energy. Often the word law is used in reference to scientific facts that can be reduced to a mathematical formula: Newton's laws of motion. In these contexts the terms theory and law often appear in well-established, fixed phrases and are not interchangeable. In both technical and nontechnical contexts, theory can also be synonymous with hypothesis, a conjecture put forth as a possible explanation of phenomena or relations, serving as a basis for thoughtful discussion and subsequent collection of data or engagement in scientific experimentation in order to rule out alternative explanations and reach the truth. In these contexts of early speculation, the words theory and hypothesis are often substitutable for one another: Remember, this idea is only a theory/hypothesis; Pasteur's experiments helped prove the theory/hypothesis that germs cause disease. Obviously, certain theories that start out as hypothetical eventually receive enough supportive data and scientific findings to become established, verified explanations. Although they retain the term theory in their names, they have evolved from mere conjecture to scientifically accepted fact.(Dictionary.com)
Facts Of Evolution
(via the Cassiopeia Project)
Ironically, he was an argument against intelligent design.
As I mentioned before in Evolution or Darwin with Modification...
Darwin didn't even use the word evolution.
Darwin didn't even use the word evolution.
| Darwin's theory is all about descent with modification by means of natural selection.|
Since descent with modification is a very natural phenomenon, it may prove valuable to start with a look there. Are there any clues to the nature of Nature?
Nature, a word of Latin origin, itself relates to origins. That is to say, birth, bringing forth. It is the word we use to name the essential quality of existence. Life, the universe, and everything. Coming into existence, is being born from and within a context. That context is Nature. This quality of existence includes the inevitable relationship to what is around. That includes both the living and non-living environment. And these are always changing!
Natural history reveals a stunning array of non-linear or seemingly chaotic iterations of both small and enormous patterns that appear to be determined largely by the start conditions. This is also seen in Chaos theory. Different start state, different pattern and different result. Even small differences at the start develop to a very large difference in result. The pattern is unique to those conditions.
Although a tricky question in some cases, there is a general way to determine this.
When the different forms of life are so different as to be unable to reproduce viable off-spring together, (and this can be for a host of reasons) they are recognized as distinct species.
In biological science, the form of an organism is called it's phenotype. Phenotype being the sum of observable physical and behavioral characteristics manifested by an organism, as opposed to the set of genes , the molecular blueprints. That difference, the DNA is called genotype. A genotype is the genetic constitution present in every organism, known as the genome. It is all the sets of genes for protein, development and regulation code for that organism. It is of note though that it is possible for organisms to have the same genotype but different phenotypes. This is usually due to environmental or developmental influences. The reverse is true too. Different genotypes can develop a similar phenotype simply by convergence. This can happen when the different organisms' environment or ecology are similar enough to have the similar selection pressures.
There is a great deal of simultaneous continuity and change in nature. Over the course of natural history, both the living (biotic) and non-living abiotic) forms change, while in other aspects, they have changed little over eons. The biotic and abiotic also interact and influence each other in significant ways. All this, over time, can be seen to have contributed to the diversity of life forms and the environment.
You must put forth some effort in order to live, eat and reproduce.
Clearly, all the resources for living are not of infinite availability or supply. This creates a condition that Darwin called a struggle for existence. One must struggle in varying degrees with the conditions of the environment, such as heat, cold and the weather, as well as in varying degrees there are situations where one struggles in competition with other beings. However, there can be advantages in cooperating as well.
No matter the means to survive, you have to hustle to live.
2. Bad Stuff happens.
Not everybody survives this struggle with enough offspring to continue.
Death, it happens. Predators, competition, old age and illness are vulnerabilities that could be fatal to the mal-adapted. And death comes not only to the ones unsuitable to the conditions. Sometimes it happens through no fault or defect or deficiency. Natural disasters don't always seem to be so fussy who's in the way. There are no guarantees that even those in harmony or suitable to the living conditions are going to avoid failure to reproduce into the future during stochastic events. Therefore, those that reproduce in greater number than needed solely to replace the individuals will likely have better chances of having surviving offspring.
To maintain continuity there must be an excess of offspring to offset loss.
3. Variation happens.
Variation exists in the offspring, they are not exact copies.
The surviving offspring have a constitution and appearance that is not identical in every way to the parents. In sexual creatures, the offspring are a new mix of genes from both parents. Circumstances during development and not only design can cause this too. Variation in genetic composition and/or appearance can also occur by factors in the environment before, during and after development of the offspring. Although this variation can be the result of the process of sexual reproduction or as in asexual organisms which reproduce clones, point mutations that occur spontaneously.
Variation in the population exists.
4. Stuff gets handed down.
Offspring traits and variations are inherited.
Each parent contributes 50 percent of the genes in their children. Therefore a mix of the parental genes are present in the descendants and are passed on. Genes that made certain traits possible can and may be there in the offspring. Mind you, they will be in some measure be present in the offspring of their relatives. A type of fitness that is known as inclusive fitness.
Children get their genes and traits from their parents.
5. Good stuff happens.
Inherited variation will sometimes be better suited to ecology.
All things being even, sooner or later, a small advantage improves the individual's chances of contributing to posterity. Some of the variations will have a quality that assists in the struggle of life, others assist in covert ways. Nonetheless if there is any opportunity which gives even the most minute advantage in reproduction of the individual's traits, that's an "evolutionary" good thing.
Some traits will be adaptive and enhance the individual's ability to survive and reproduce.
Darwin's study was in what ways and conditions does life change forms. Do individuals change in a life time or do only populations change? Does it ever happen suddenly or only over many generations? Darwin had some ideas about this. In 1859, he published his book, The Origin of Species.
He observed that for all phenotypes, existence has requirements for and consequences on, the reproduction of their genotype.These lead to changes in the number of certain phenotypes (kinds of individuals) and their genotypes (kinds of blueprints) being born and surviving in a population over the generations. He saw that when populations are reproductively isolated from others, these populations can eventually become more than just variations within a type. When they are only able to reproduce with their own kind, they are recognized as a true species.
What is not always immediately observable or understood is how the changes in off-spring may occur. In an age before the science of genetics, Darwin didn't know about genes exactly, or how they do what they do. But was right about one thing and awfully close to another. He speculated there were gemules that came from each parent with their traits and that in reproduction the traits are inherited by the offspring.
Darwin's theory wasn't really exceptional in the observation that life forms change and appear different. Many before him had noticed this. It was exceptional in that he saw a way how living "types" or species have come about and are continually changing into new stuff all the time. Beginning with the observation that in the process of life and reproduction there is modification accompanying inherited traits, some of which are adaptive, and that extinction follows insufficient reproduction. Over time, even small differences could accumulate to result in a radial change. He saw one important way the origin of species could come about based on this and the fact that not all succeed to reproduce. Darwin's expression of the process was, natural selection. These words are familiar but to many, they are understood in different ways. Many, including some biologists refer to natural selection as a mechanism. I am of the opinion that better insight comes from the view that this is pertaining to an organic process, and a mechanical metaphor is inappropriate.
In order to illustrate this process a mechanic process will do. Darwin mentions the selection of characteristics or traits that human domestic breeders make. There exists a variety of traits in the individuals of a population. He tries to illustrate how those individuals which have traits selected ( chosen by the breeder ), are the ones allowed reproduce and have the offspring, who in turn, carrying these traits flourish. Those without the favored traits are not preserved as breeding stock, and are therefore their traits are eliminated from any substantial contribution to the future generations.
By the intervention of the breeder/selector those individuals with these traits are the ones which increase in the population. Many of their offspring strongly exhibiting the favored traits are advantaged in that, again they are the ones selected to reproduce more of their kind. This leaves even more individuals with those traits in the population. Consequently, over several generations, this has an influence on the composition of the population. The differential in their reproduction relative to others in the population results in more individuals with these traits existing in the population. Eventually the entire population can be exclusively composed of only individuals of these traits. Thus the breeders, by what traits they favor and the individuals they select to breed, can change the entire variety of traits from that present in the original population. The result can be radical divergence of type, like nothing before.
The analogy used incorporates intent on the part of the breeder as selector. This is used to show what happens when certain individuals contribute more of their inherited traits to the composition of the population. Superimposing the intentional, or artificial method of selection, onto the natural shows why it is an analogy. They are not the same in every respect, only in the resulting effects in the population.
Nature, as the selector of preserved traits, is not a person. Not even as abstract person and does not have intention, only consequences. The criteria are not determined by will or forethought. The nature referred to is another way of saying all the concrete consequences of real circumstance in nature, and that includes random chance. Everything that interacts with whatever exists in the context of the natural world, nature itself, will experience the consequences of that interaction. The criterion for natural selection is contributing to posterity. Individuals not surviving long enough to reproduce in the circumstances pretty much eliminates the chance to do this.
Neither nature, nor individuals and their offspring in nature, have to have intent for this to occur. It is simply the consequence of the way things are. This is in spite of some effects of nature which appear to be what a conscience selection would make. Nature does not stand apart from the entities within it and choose which individual of what trait lives, which will die. Nature is the context where elimination and preservation are occurring. Even through the word selection may lead us to project our own perception of selection as a conscience process, nature, when not personified is another word for the circumstances. The process of selection, is really the consequence of circumstance.
Darwin did not mean to imply some plan or intent on the part of nature. A variety of traits in a population exist, a variety of circumstances determines the rate by which individuals of certain traits reproduce. Inherited traits are passed on to descendants, and if those traits do not get in the way or assist, even in the slightest, in differential reproduction, the result will influence the variety of the population in the future.
Natural selection, to many people, directly translates as the now famous survival of the fittest. This expression was coined not by Darwin but by a man named Herbert Spencer. Those that are fit survive and those that are surviving are those that are fit. Now, very different interpretations of what survival is and what being fit means are possible. If this expression is taken literally, the real meaning is confused. One may even conclude that it is not scientific since the form is one of repeating the same thing, a tautology. For one thing, this is an expression, it was coined for effect or display. It is not a formal scientific statement and was never intended to be so. The expression however does not detail the theory behind the rhetoric. Survival does not mean only that it is the individual that survives. No individual, survives forever. Is that the success that is meant?. It makes it so none are, nor can ever be. Fit by the criteria of survival alone is not how it need be.
A component of this type of survival is the perpetuation of the genes for those traits in the descendants. The genes are the biological coding, the means to manifest traits in individuals. If those genes are not present in future generations ... it's called extinction. Darwin, living in a time when genetics was yet to be developed, referred to it as the passing on or inheritance of some particle or material which determined the characteristics which are contributed by the individual into future generations. Darwin was not quite able to nail down the most accurate process of inheritance. alt=hough it seems pretty clear that without the benefit of genetics he did appear to have a ballpark notion of the modification process of the descendants. The combination of both parents contribution of encoding material generates the variety of phenotypes manifest in populations. This variety is the essential quality which selection can act upon.
The selection occurring may be because of a trait, but it is the individual and eventually its descendants that is selected. The result of this selection eventually becomes manifest in the population. Long winded maybe but still on the money. That, is the whole point. The types of change of life forms we have come to know as evolution occurs within the lineage not the individual. Any means by which individuals can accomplish this is valid. If indeed, this other way does succeed in passing on the genes then the requirement for survival, the legacy of that lineage's genes and associated traits is fulfilled. Still, variation in what is present in descendants is part of the legacy the raw material of and for change. Environments do not remain the same indefinitely, the differences in what was provides the chance for some of the differences to have opportunity.
The changes in the environment and the descendants may occur at different speeds but environments are always dynamic and so are the changes in the descendants. Variation in the descendants is not always a change which would be harmonious with the environmental changes but the chance that some of the variations could be is better than remaining completely unchanged and having little or no chance at all.
These changes are found to occur in many ways, one vital one is genetically. In non sexually reproducing organisms as well as sexually reproducing ones. Sometimes the genetic changes occur very randomly and other times not so randomly. The advantage of variation is, though not always immediate, it can produce a means of covering if not the all bets, at least more of them. A quality that can provide better opportunity in the survival of individuals with variations. The variation can result in preserving or enhancing a suitability of the individual to fulfill the survival requirement mentioned earlier.
Now as to fitness, fit does not necessarily mean only the physical condition of the individual. We use fit in everyday language in more than just this way. although an individual in good physical shape will likely have the qualities to manage better in the task of survival, i.e. dealing with the environment, competition for mates, disease, predators, or finding and obtaining food, this may not always be the only conditions leading to successful reproduction. If a particular shirt does not " fit " we are apt to mean that either it is not harmonious in some way with the rest of the ensemble or that it is the wrong size. Either way fit is taken to mean that it is suitable to the context, whatever that may turn out to be. Suitable to the context, is the same as saying fit the criteria. What this fitness really comes down is the qualities possessed by the individual which perhaps in varying degrees allows the individual to accommodate the circumstances in which it is in and accomplish reproduction in and in a way that continues the line. Another word for this suitability is adapted. If an individual lacks sufficient suitability it most certainly will lead to a result of fewer offspring and if the lack of suitability is also in the offspring ...well. Taking this to the level of the population, is what extinction is. There is no conscience selection, the consequence is that those who have a greater contribution through descendants will eventually be what's around in the future.
In case this still isn't clear, as an example, a rabbit, even in the best of shape, healthy, muscles all toned, bright and alert, still is not fit to live in the ocean. It's traits are not suitable to that context. The act of reproduction and its completion to a successful result would to put it mildly be hindered and any opportunities for the future of its lineage drastically limited. One need only look at the ubiquitous and dramatic natural changes such as floods or droughts to see that conditions do not remain the same forever. This example does even begin to take into consideration the infinitesimal small and gradual changes which are also occurring all the time. And, hey, physical environment is only one aspect of the total context of nature. Keeping this in mind isn't such a bad idea. It is not only one factor that can determine fitness, the whole is the context and even the slightest difference or change can have an important influence, especially if it is a trend which lasts over a long time.
Survival is the successful differential reproduction of individuals inheritance into the future through descendants. Fit is the suitability and harmony of the individuals traits within the context or environment in which it exists that permits or in particular provides an advantage for this survival to occur. Overall the effects of these things on individuals are manifest in the population. Changes in life forms in populations are mediated by the individuals that compose the population. Changes in the individuals can lead to changes in reproduction between them.
Major changes in the composition of the population is the how Speciation is recognized. The main determinant for a species is viable reproduction, any inherited modification blocking, or eventually blocking reproduction between individuals will likely lead to different species. This process of change is a factor in the origin of species. It is by keeping these definitions in mind that I hope you will have a different perspective of what descent with modification is all about...
And realize that evolution is indeed a Theory, in the sense that it is indeed a fact.
© 2013 MU-Peter Shimon