December 15, 2012
by Martin Odoni.
What do the following terms have in common?
Microevolution / Macroevolution
Answer. They are all bandied about routinely and flippantly by Creationists, who never get the definitions right. An attempt to correct these bad definitions follows…
“Darwinism” (or even more inaccurately, “Darwinianism“) is usually used by Creationsists to describe the entire school of Evolutionary thought, when in fact it only describes one small area i.e. the notion that species evolve by natural selection, as stipulated by Charles Darwin. Creationists, as a rule, tend to think both that Evolutionary thought began with Charles Darwin – it did not, Ancient Greeks such as Anaximander were the earliest known scientists to postulate the concept some two thousand years before Darwin – and also that it has barely moved since Darwin’s time either. Slightly better-informed Creationists (but there aren’t many of them) might acknowledge the work of Stephen J. Gould, but assume he is the only Evolutionary scientist since Darwin’s time to have done any new research, and sometimes suggest, quite absurdly, that his theory of Punctuated Equilibrium actually refutes Evolution, which again it does not.
“Evolution” is usually defined by Creationists as meaning an animal, “suddenly transforming into a different animal”. This is meant to imply some kind of magical metamorphosis into a different shape, a little like Optimus Prime transforming into an articulated lorry. Less sorcerous, but hardly less silly, it is sometimes put forward to mean the life-form giving birth to a creature from a completely separate species. In fact, evolution means life-forms (not just animals) changing their dominant form over lengthy periods of time in response to their environment, with the transition being extremely gradual and barely perceptible, usually occurring in tiny increments over many generations. Creationists further assume that the “different animal” the life-form transforms into will be a contemporary of the original form e.g. a crocodile gives birth to a duck. But where evolution occurs, the new life-forms that very gradually emerge over long generations will be a new species that did not exist at the time of the original.
Sometimes Creationists give “Evolution” a far broader and even more misplaced definition, as being the school of science studying the origins of life on Earth, or even of the origins of the Universe. In reality, the study of the origins of life on Earth is the field of Abiogenesis, while the origins of the Universe, a pretty enormous subject in its own right, are studied by the fields of physics, astronomy and cosmology.
“Microevolution” and “Macroevolution” are usually defined by Creationists, when grudgingly forced to concede ground on the issue of whether there is evidence to support evolutionary theory, as meaning very slight changes to a creature’s DNA as opposed to fundamental changes. This is actually close to being a good definition, but once again the tempo is completely misjudged. Microevolutionary changes usually take place over a few years, whereas macroevolution can, and usually does, take place over thousands of years. The common position taken by many Creationists today is that microevolution is real, whereas macroevolution is not, for where microevolution occurs it is within the boundaries of a species, whereas macroevolution would carry a life-form beyond those boundaries, an event that has never been witnessed. The fallacy is two-fold. Firstly, these ‘boundaries’ are never really defined, nor is any evidence cited to support the notion that they exist. Secondly, macroevolution does not occur during the lifespan of a single organism. It happens over many succeeding generations and across whole populations.
“Natural selection” is usually defined by Creationists as the assertion that, “Life just happened by chance.” This mal-definition is perhaps the grossest of the lot, as natural selection, if anything, means the reverse. Certainly chance plays a role in the process of evolution, but natural selection is not that part, and the very use of the word ‘selection’ should make clear that developments are not just happening at random. Natural selection actually means, from different specimens of the same life-form, those with the individual traits best-suited to their environment are most likely to survive, and so pass their traits onto descendants. For instance, in an environment where there is very little food at ground level, but a lot of fruit in the branches of high trees, a taller or longer-necked specimen of a quadruped is likelier to survive than a smaller counterpart, as it will be easier for the taller one to reach food. And as the taller one is likelier to survive, it is also likelier to mate and to have offspring. These offspring will inherit much of its genetic information, including the extra height/neck-length, and so future generations are likelier to be taller/longer-necked than the present average.
“Theory” is usually defined by Creationists – and in fairness by much of wider society – as just an idea or an elaborate guess. This immediately casts an illusion of uncertainty over whether evolution is a reality or just a possibility. Hence the exhausted phrase, “Evolution is just a theory.” But in science, such a vagary would not be given the title of a theory, but instead it would be categorised as a hypothesis. A better alternative name for a theory is ‘explanation’. A theory in scientific terms means an explanation for a phenomenon that is not only allowed for, but also fully supported, by all the available evidence, and which has stood up to all of the most rigorous testing and analysis by qualified peers. Quite simply, in the realm of science there is no greater badge of confidence that can be bestowed upon a hypothesis than the name ‘Theory’. If Creationists don’t think that’s true, perhaps they could suggest other, more authoritative titles that are used by science instead? So far, this hasn’t happened.
“Transitional form” is usually defined by Creationists as meaning, “Half one animal, half another.” This usually conjures up mental images of mythical creatures like the Minotaur or the Hippogrith, which would essentially appear to be bits of one animal fastened to bits of another. Probably the most notorious phrase that this idea has given rise to is the Creationist mantra, “There’s no such thing as a crocoduck!” often accompanied by a picture of an imaginary creature with the head of a crocodile and the round, feathered body of a flightless bird. This shows a fundamental misunderstanding, not only of what evolution means as a whole (see the section on “Evolution” above), but also a flawed preconception of the animal kingdom as a collective, and a very rigid and limited notion of what a transitional form would be. To address the first point, Creationists go in with an assumption that the Earth has, so to speak, a ‘quota’ of animals. Every species on Earth has always been there, and always will be, barring extinctions. These life-forms are seen in the Creationist mind to be ‘completed’ i.e. they are the definitive form for their species. Any variation away from one species, Creationists assume, could only mean it carries them into the shape of another one that is already there. There may be a generation or two of transition, where there is a life-form that is part one, part the other, but the transition is assumed to be immediate. Hence, if a crocodile ceases to be a crocodile, it will evolve into one of its contemporaries, perhaps in a couple of stages, e.g. a duck. Ergo, the ‘crocoduck’. The possibility that the end-form might be a new species altogether never seems to enter the Creationist’s thoughts. There is no ‘set quota’ of life-forms in nature, no guaranteed catalogue or line-up. There never has been. And a transitional form, in truth, is not on a clearly marked dividing line. All life-forms that have ever existed on Earth since the earliest protozoa have been a transitional form. Even the form of modern humans is no more an ultimate destination than the so-called ‘Missing Link’ was. The transition is a gradual process, and homo sapiens can be classed as the transitional form between homo erectus and whatever is to follow. But equally, what is to follow will be a transition form between homo sapiens and whatever is to follow again, and on and on, indefinitely, and all the while with countless sub-categorisations in between. A transitional form is not just a freak mutant or one of the Wuzzles (remember them from the 80’s? Google it to refresh your memories). It is, quite simply, a single step on a ladder of infinite steps.
“Vestigial organ” is usually defined by Creationists as meaning, “useless remnant of a body part inherited from a remote ancestor”. This definition is almost correct, except for the epithet, ‘useless’. Creationists always insist on the epithet being included though, as a method of discrediting the whole concept. A vestigial limb is indeed a remnant from ancestral forms, and one that natural selection is gradually ‘phasing out’ (for want of a better term) due to general disuse over long generations. But, while it is fair to argue that such a body part goes largely unused and so is unnecessary to the species’ survival – that’s the whole reason that it is phased out, to reduce the burden of ‘dead weight’ – that does not mean it is useless. And this distinction is important, because vestigial parts can still play a minor function. For instance, the human appendix is unnecessary, but can play a useful role in supporting the body’s immune system. By forcing the word ‘useless’ into the definition, Creationists hope to discredit the whole notion of vestigial organs, because they can then point to the uses vestigials still have and say, “See? They still play a role, so they are obviously not vestigial.” This is itself a very obvious fallacy of definition, confusing the meaning of ‘unused’ with the meaning of ‘useless’, and so mangling the definition of ‘vestigial’. The usefulness of a body part is not central to whether or not it is vestigial (it might be the reason why it is happening, but there are other possibilities). The only requirement for a body part to be vestigial is for it to be in the process of being phased out by natural selection.