Thursday, 20 February 2014

More Evolution Myths Debunked

In 2008, Michael Le Page wrote an article for New Scientist in which he listed 24 myths and misconceptions about evolution, 14 of which were specific to creationism and which, despite them being continually refuted by proper scientists, creationist pseud-scientist continue to promote and disseminate amongst their gullible audience, usually for money. I listed these in Creation Myths Debunked and added my own refutation of them.

Here I give the same treatment to the other 10 common misconceptions. You will, of course find these being trotted out by creationists in debates with evolutionists, not realising they are simply misconceptions about what evolution is and how it works, rather than refutations of it. No one could ever accuse a creationist of knowing what they are talking about when it comes to science, even a science so basic and easy to understand as evolution.

Everything is an adaptation produced by evolution.

It's easy to assume that because every species is essentially the product of its evolutionary history that everything about it must have evolved because it gave an advantage of some sort. However, this ignores the fact that genes coding for particular traits can be linked on the same strand of DNA, so if one gene gives an advantage, descendants which inherit that gene will also inherit the linked gene. It may be that the linked gene has no particular advantage at all. It might also be that the linked gene is actually deleterious but not enough to cancel out the benefit of the advantageous gene. The linked pair will still convey an overall advantage so they will tend to increase in the species genepool.

One of the explanation why sexual reproduction came to dominate early - even a form of it is normal in bacteria - is that it involved crossing over of sections of DNA between paired chromosomes, which increases the chance of linkages being broken so advantageous genes can be freed from the evolutionary drag of being linked to disadvantageous ones and disadvantageous ones can be eliminated without losing the advantageous genes. They may even become linked to other advantageous ones, giving both a combined advantage which might even be synergistic.

Gender differences can also mean that features which are an advantage to one sex are also inherited by the other. Male mammals have useless nipples, for instance. There is simply no evolutionary pressure for males to lose them, even if it was possible to isolate the genes for them in female DNA only and there is no particular disadvantage to males in having nipples.

Evolution is always a work in progress, so to speak. (Creationist quote-mine alert! It's a metaphor, creationists! Calm down!). Several characters such as wisdom teeth, Darwin's Tubercle and the human appendix are vestigial structures because there has not been enough time, given our relatively slow generation time, for us to lose them altogether or to adapt them to serve some other purpose.

The evolution of a trait might be an incidental consequence of evolving some other advantageous trait. It has been suggested, for example, that the short stature of pygmies was a consequence of them evolving early reproduction in conditions where early adult mortality was common.

Lastly, what is beneficial to one gender may be deleterious in the other. One suggestion for homosexuality in males is that it could be linked to increased fertility in females. Females with increased fertility will tend to have more children so the chance of passing her DNA on to the next generation may still be higher despite the occasional son being homosexual.

Evolution happens because of natural selection.

Natural selection, and especially the special form of natural selection, sex selection, is undoubtedly a major cause of changes in allele frequency in the gene pool, but it is not the only one.

Random genetic drift will also cause change and is capable of leading to a gene becoming fixed in a population (where all individuals carry it) or to a gene being eliminated altogether. This will happen where variations give no particular advantage. It could account for the variations to be seen in the modern human face, for example. Random genetic drift in small, isolated populations could have led to differences between populations which have no adaptive purpose.

The graphs on the right from the New Scientist article show the result of two computer simulations of the change in frequency of five genes all from the same starting point.

A related aspect of random genetic drift is the so-called 'founder effect'. A population moving into new territory and becoming isolated from the parent population will normally be a random selection of individuals (not always as I'll explain in a moment). This effectively resets the starting position for genetic drift and the new population will randomly drift in different direction to its parent population. Include new random variations and over many generations the two populations will gradually, and randomly, drift further apart, even without any natural selection. This change alone could be enough to make it impossible for successful interbreeding to occur if the two populations ever come into contact again. All it needs is time.

The exception to the selection of the founder population being random would be a situation where individuals in a population had an ability which allowed them to move into the new territory. The founder population would thus be a self-selecting non-random sample. It could also be that a founder population expanding further into a new territory is actively selecting for success in that new territory so the expansion itself becomes part of the selection process. This can lead to very rapid diversification from the parent population in a newly-isolated population. In terms of cultural evolution, how much of the 'pioneering spirit' of present-day Americans is due to the founder population being selected for it in the first place and then the migration west further selecting from an already pioneering population? Who ups sticks and moves into new lands if not pioneers?

Some people have proposed that genetic drift alone could account for far more evolution that is generally acknowledged.

Incidentally, can anyone say where 'speciation' occurred in that process? It couldn't have been when the populations initially became isolated because they were then indistinguishable and fully capable of interbreeding. In fact, speciation is not an event but the incidental result of a process spread over time - which is why creationist charlatans prime their credulous victims to keep asking why no one has ever seen a new species come into existence. They know no-one has because they know it doesn't happen like that. It's as idiotic as arguing that you can't drive to New York because no-one has ever seen a car materialise from nowhere in New York.

Yes folks! It's that easy to fool a creationist and get them to part with their money. They are the scientific equivalent of people not knowing how cars move along a road and who refuse even to acknowledge that they do so or that roads exist.

Natural selection leads to ever greater complexity.

Natural selection leads to improved ability to reproduce in the given environment. This may or may not involve changes in complexity. In the case of internal parasites it more often than not leads to greater simplicity. Parasitic worms and flukes for example may even lose their gut and simply absorb nutrients from their host through their skin. Adult tapeworms are little more than a head with hooks for attaching themselves to their host and maturing egg cases to be excreted and ingested by a new host.

Because redundant structures tend to carry an overhead in terms of being a drain on resource, and a risk in that they can be injured or cause problems - wisdom teeth, appendix, for example - that natural selection will gradually eliminate them giving less complexity. Atrophied organs and structures are examples of reduced complexity.

It has been proposed that complexity in the genome - which is where increases in complexity will really occur - may be more likely in conditions where natural selection is weak.

Michael Le Page explains it thus:
Suppose an animal has a gene that carries out two different functions. If mutation results in some offspring getting two copies of this gene, these offspring won't be any fitter as a result. In fact, they might be slightly less fit due to a double dose of the gene. In a large population where the selective pressure is strong, such mutations are likely to be eliminated. In smaller populations, where selective pressure is much weaker, these mutations could spread as a result of random genetic drift... despite being slightly disadvantageous.

The more widely the duplicated genes spread in a population, the faster they will acquire mutations. A mutation in one copy might destroy its ability to carry out the first of the original gene's two functions. Then the other copy might lose the ability to perform the second of the two functions. As before, these mutations won't make the animals any fitter - such animals would still look and behave exactly the same - so they will not be selected for, but they could nevertheless spread by genetic drift.

In this way, a species can go from having one gene with two functions to two genes that each carry out one function. This increase in complexity occurs not because of selection but despite it.

Once the genome is more complex, however, further mutations can make a creature's body or behaviour more complex. For instance, having two separate genes means each can be switched on or off at different time or in different tissues. As soon as any beneficial mutations arise, natural selection will favour its spread.

Michael Le Page, Evolution Myths; New Scientist; 16 April 2008

Evolution produces perfectly adapted creatures.

This quite simply flies in the face of the evidence. A perfectly adapted species will always survive and, as we shall see in the next topic, most haven't.

In fact, you don't need to be perfectly adapted to be successful, you just need to be adapted well enough to be more successful than your rivals. Competition will often lead to evolutionary arms races in which two species will evolve in ways which are ultimately of no advantage to either.

A giraffe's stupidly long neck, which has necessitated it evolving ways of pumping blood up to its brain and then having to overcome that mechanism when reaching down to drink to avoid a brain haemorrhage, then accelerating it again when raising its head back up to avoid losing consciousness, is all to overcome the acacia tree's long trunk which it has had to evolve, and now needs to find the resources to grow, to avoid having its leaves eaten by giraffes. Both adaptations now mean the two species have to make a huge investment in simply growing their adapted bodies and yet neither is perfectly adapted. Acacia trees still have many of their leaves eaten and giraffes find drinking water difficult and standing up quickly from drinking even more difficult, making them vulnerable to crocodiles and other predators, but they still can't reach all the acacia leaves.

The panda's true thumb is committed to another role. So the panda must... settle for an enlarged wrist bone and a somewhat clumsy, but quite workable, solution.

Stephen Jay Gould, 1978
Humans are not perfectly adapted to living in an environment which contains malaria, trypanosomes, viruses, pathogenic bacteria, parasitic worms, alcohol, carcinogens and saturated fats, otherwise we would need fewer doctors, and we humans would not suffer from scurvy if we don't eat enough vitamin C just because a gene got broken way back in our evolutionary history so we can't make our own vitamin C anymore like most mammals do.

Whales, seals, manatees and marine turtles are not perfectly adapted to living in water because they have constantly to return to the surface to breathe. Many insects and birds in temperate zones can suffer huge population crashes in cold winters or dry summers and for most species, just as it was for most of humanity for most of our history, life can be nasty, brutish and short and a real struggle for survival. Very few wild creatures, sentient or otherwise, die peacefully of old age in their sleep.

There are many ways of dying - very few of them are pleasant - but evolution can only occur if a trait can be passed on. This means evolution can only have any bearing on what happens after an organism has bred successfully if survival helps the success of its descendents. In most species, survival of the previous generation after breeding is detrimental to the survival of their offspring because they compete for resources, so mechanism for avoiding death in later life will not only not evolve but there may even be pressure to evolve mechanism to ensure it happens relatively quickly.

None of this is perfect adaptation from the point of view of the individual.

Evolution promotes the survival of species.

This also quite simply flies in the face of the evidence. Some 90% plus of all known species from history are extinct. Of course, some of these went 'extinct' by evolving into another another species - Homo heidelbergensis evolved into H. sapiens and probably H. neanderthalensis, for example - but most simply went extinct like H. neanderthalensis, most probably because it was over-specialised to ice-age conditions.

The problem with evolution is that it is unplanned and undirected. It has no prior knowledge of the future and has no ability to plan for it even if it did. Evolution by natural selection is driven by change in the environment but that change might be reversed in the future or may changed far more quickly than the species can evolve. A species can find itself specialised for living in an environment which no longer exists.

A species' environment can change quickly because a new predator has evolved or moved into the habitat - think dodo, passenger pigeon or Tasmanian wolf. Catastrophic climate change causes by, for example, a cosmological event, or continental drift leading to changes in ocean currents and weather pattern have also caused mass extinctions in Earth's history. No matter how creative the evolutionary process might be, it can't always cope with catastrophic change. The fact is there are far more ways of going extinct than there are of surviving.

Sex selection may be another way in which a species can be driven to extinction simply because it can't put a stop to an increasingly harmful process. For example, female peacocks select males with the largest, most conspicuous tails. They have no choice in the matter and males must evolve larger and ever more conspicuous tails which females can't help but choose. Yet males will become increasingly prone to predation and will find escape ever more difficult. The male population can become threatened and yet fewer males actually increases male evolution in a deleterious way. With no males, the species goes extinct. The only way this can be avoided is if males are incapable of evolving larger and more conspicuous tails for some reason, or females suddenly switch their preferences - and what would drive that switch other than possibly the random genetic drift of several genes involved in the selection behaviour?

Evolving to extinction - the eventual fate of almost all species - is surely evidence that there is no intelligence involved in the process. It can only be the result of a blind, undirected and unthinking, amoral process.

Mike Huckabee. Young Earth Creationist. Southern Baptist Preacher.
Candidate in 2008 US Republican presidential primaries.

It doesn't matter if people do not understand evolution

Well, no, on an individual level it doesn't matter if someone lives their entire life no knowing about evolution. Before 1859 almost no-one knew about it. Consequently even highly educated and intelligent sceptics like Thomas Paine and Thomas Jefferson could not see an answer to the teleological argument and settled for the idea that there must be a creator of some sort.

It's a great shame though that, because they've been lied to, or made afraid some terrible fate awaits them if they acquire some forbidden knowledge which contradicts an ancient superstition, that some people miss out on learning one of the most remarkable and fascinating processes on Earth and the process which is responsible for the huge diversity of life. I know no-one who understands evolution who isn't perpetually awestruck by what it has produced and how it makes sense of an otherwise bewildering collection of living things. Most serious biologists find the knowledge of how they are related to every other living thing, deeply spiritual and humbling.

The explanatory power of Darwin's theory of evolution which needs only three easily observable things to be true, and yet which can account for seemingly hugely unlikely things becoming inevitable through a process of accumulation of small differences over time, is immense and has application far beyond explaining the evolution of species.

All that is required is:
  • Inheritance of traits.
  • Imperfect replication of those traits to give variation.
  • Differential selection of those variations.

Clearly, this can apply to many systems, not just biological ones. The only other thing required is sufficient time, and that depends on the generation time.

Imagine if Mike Huckabee ends up as vice-president of the US - a mere heart attack away from the top job. Would you feel comfortable if the world's biggest superpower was run by a man who rejects evolution, thanks to the support of tens of millions of people who also refuse to accept the truth?

...Any leader who thinks evolution is a matter of belief is arguably unfit for office. How can someone who dismisses the staggering amount of evidence for evolution assembled by researchers in myriad fields possibly evaluate more subtle scientific evidence for, say, climate change?

Michael Le Page, Op. Cit. [Written in 2008]
But be that as it may, if individuals need to imagine they are so important they must have been deliberately made by some creator of the universe and it made everything else by magic just for them, because Bronze-Age people in the infancy of our species couldn't think how else it could have happened, the pleasure of enjoying the real magic of reality is lost to them. Their need to feel super-important is preventing them knowing how they really fit in with everything else on Earth and understanding how very special and fortunate they really are to be alive, the products of this process and capable of learning and understanding it.

But why should these unfortunate individuals be allowed to prevent others from learning about it?

Because the next generation is going to provide us with the scientists, doctors and bioengineers on whom we will increasingly depend for food, medicine and technological progress. Telling them they cannot trust science and that science is worthless will lead to two things. I disagree with much of what he says, but on this, Old Earth Creationist and evolutionary scientist Francis Collins hits the nail on the head:

By attacking the fundamentals of virtually every branch of science, it [Young Earth Creationism] widens the chasm between the scientific and spiritual worldviews, just at a time where a pathway toward harmony is desperately needed. By sending a message to young people that science is dangerous, and that pursuing science may well mean rejecting religious faith, Young Earth Creationism may be depriving science of some of its most promising future talents.

But it is not science that suffers most here. Young Earth Creationism does even more damage to faith, by demanding that belief in God requires assent to fundamentally flawed claims about the natural world. Young people brought up in homes and churches that insist on Creationism sooner or later encounter the overwhelming scientific evidence in favor of an ancient universe and the relatedness of all living things through the process of evolution and natural selection. What a terrible and unnecessary choice they then face! To adhere to the faith of their childhood, they are required to reject a broad and rigorous body of scientific data, effectively committing intellectual suicide. Presented with no other alternative than Creationism, is it any wonder that many of these young people turn away from faith, concluding that they simply cannot believe in a God who would ask them to reject what science has so compellingly taught us about the natural world?

Francis Collins. The Language of God

Mit Romney. Young Earth Creationist. Mormon.
Republican candidate, 2012 US presidential election.
Of course, it's in his first paragraph above that Collins identified the real danger of Creationism. If his second paragraph were true of a wider population than those who do reject faith because science shows it to be wrong, then more power to their elbow, I say. However, it is far more likely that they will remain anti-science and superstitious as we can see from American society today where 25% of the population still believe the sun orbits a 6000 year-old Earth which is the centre of the Universe and Noah's Ark was a historic event. This in the world's largest economy where one would expect to find the highest standard of general education, instead of one of the lowest for any developed economy.

And these religious fundamentalist could be controlling the world's largest nuclear arsenal.

We need political leaders voted into office who understand how evolution informs decisions regarding fishing policies, agricultural policies, antibiotic use and research, ecology, environmental and conservation policies, virology, epidemiology and public health policies and we need political leaders who understand how to evaluate evidence and base decisions on it. The last people we need are those who not only don't understand science and evolution but actually believe it to be wrong because they know no better than Bronze-Age nomads did but can't entertain the possibility of being wrong and so turn blind eyes to the evidence they don't want to see.

Ironically, the religious right in America has created conditions in which those best fitted to lead America - the scientists and intellectuals - are effectively debarred from office because they don't have the right irrational superstitions and phobias.

'Survival of the fittest' justifies 'everyone for themselves'

Firstly, even if this were true it would be nothing more than an argument from consequences. The truth of science does not hang on whether the consequences are convenient or not but on whether the evidence supports it or not. Atomic theory is no less true because atom bombs are destructive and nuclear war would be unpleasant.

The term 'survival of the fittest' is often falsely attributed to Charles Darwin. In fact, it was coined by Herbert Spencer. It is widely quoted by creationists if for no other reason than they can disguise their straw men with it by making 'fittest' mean whatever they want it to mean. If it means anything in evolutionary terms it refers only to the last of the three stages I listed above - differential selection from amongst variations. Trying to apply this to social situation, in particular the business or political world, to justify a dog-eat-dog morality and trying to drive the competition out of business by any means available neatly ignores the replication and inheritance stages.

Strangely, those who argue against evolution on these grounds often have a close relationship with big businesses which justify their amoral business ethics by misquoting Darwin, just as the social Darwinists, also usually from the political right, do. Nothing wrong with Darwinism when it suits you, it seems.

Of course, the 'fittest' may be the most cooperative, the most conciliatory, the most loving and affectionate or the most altruistic. Fitness to reproduce, which is what evolution by natural selection actually results in, does not often mean the most aggressive. It can mean the most fertile, the cleverest, the tallest or fastest, the best able to run and hide or the best able to tolerate extremes like temperature, salinity, pH or pressure. Or it can simply mean the best able to find and use resources. The peacock butterfly did not evolve mammalian-looking eyes on its wings nor did the zebra evolve stripes by being aggressive.

In human evolution, it was almost certainly the evolution of the ability to empathise with our fellows and to work cooperatively which led to our present level of technological development and societies bases on mutually agreed rules of interpersonal conduct. Had we adopted a dog-eat-dog strategy on the African savannah it would have been the wild dogs, cats, snakes and eagles who ate us. We 'won' by being the best at being cooperative.

Paradoxically, it's probably by being aggressive in the way they falsely accuse Darwinists of supporting that religions have gradually eliminated the opposition until we are left with two major religions now squaring up to one another and threatening the future of humanity in order to prove which one has the best imaginary friend.

Evolution is limitlessly creative.

In his book, Climbing Mount Improbable, Richard Dawkins introduced the idea of a fitness landscape - a theoretical world in which all the possible peaks of fitness existed. Looked at without any appreciation of how evolution is a slow, cumulative process, it might appear that there is no way a species could have got from the plains to the top of a peak in a single jump - the origin of the creationist straw men, "no one has ever seen a chimpanzee give birth to a human", or "the eye is too complex to have evolved spontaneously", etc.

In reality of course, the species has strolled slowly and inevitably up a gradual slope in this fitness landscape until it finds itself on the peak. There was no intent involved and no deliberate, massive and hugely unlikely jump anywhere in the process.

However, some fitness peaks may really be unclimbable and for reasons not entirely unrelated to creationist's misconceptions, feigned or otherwise. It could be that there is no gentle slope and the peak could only have been climbed using impossible jumps. Michael Le Page uses the example of evolving two-way radio communications.

The advantage of two-way radio communications would be considerable but how could any species climb to this peak? In fact, two different technologies would need to evolve independently yet each would only be an advantage in the presence of the other. There is no advantage to evolving transmitters if receivers don't exist and there is no advantage in evolving receivers because even being able to detect naturally-occurring radio waves such as those from lightning would not provide any useful information. For an intelligent designer, this would be no problem at all. If two-way radio communication was required it could be created fully formed, as creationists tell us wrongly that so many structures and processes were. The fact that nothing alive has in-built radio communication is because they were 'designed' by a mindless process with no plan and in which the required big jumps are impossible.

So, although evolution is undoubtedly hugely creative, there are limits.

Natural selection cannot explain homosexuality.

It seems to be a curious feature of evolution deniers that they are almost invariably from the extreme right politically and are obsessively homophobic. It's almost as though they are conditioned to look for reasons to hate, as though they need to feel better about themselves by denigrating others. But even homophobes who do accept evolution will use this one to try to prove that homosexuality is really just a choice of lifestyle. I wonder when they chose to be heterosexual!

In fact we know that some traits are linked because the genes coding for them are close to other genes in a chromosome. We also know that some genes have more than one function and a function which can change over the lifetime of the organism. I have already mentioned above how homosexuality in males (and it is common in many species despite the claims of religious bigots who believe their homophobic god created everything) could be a consequence of increased fertility in females, for example. The advantage of increased female fertility could out-weigh the disadvantage to the genes of producing a few homosexual males. But homosexuality is not always an exclusive process anyway. Many homosexuals are in fact bisexual and quite capable of having children.

Simple reasoning shows that evolution cannot explain homosexuality - how would a homosexuality gene get selected for? Why have the genetic traits predisposing to homosexuality not been eliminated long ago?

Any homophobic evolution denier
Any advantage of an evolved trait might not express in prolonged survival of the individual or even in an improved ability for a specific individual to reproduce, but in the survival of close relatives. After all, evolution is increasing the frequency of the 'selfish' gene in the species gene-pool, not in making specific carriers better able to produce offspring.

It has been proposed that one explanation for the increased tendency for boys with older brothers to become homosexual - something which apparently increases the more older brothers there are - is because male foetuses may leave something in the mother's blood which increases the possibility of future sons being homosexual. This trojan horse strategy would give older brothers an advantage in a future competition for mates. I don't know if this is generally accepted now, but at least it illustrates one possible mechanism for how homosexuality could evolve by natural selection.

It could also be that homosexuality is a consequence of sex selection. I have already mentioned the peacock's tail where female sex selection is pushing males to evolve traits which appear to be disadvantageous. It could be that homosexuality is also the result of females selecting traits in males which are linked to homosexuality, not necessarily in their partners but in their children. Similarly males could be selecting traits in females which increase the likelihood of her daughters being lesbian.

It would be interesting to see how creationists explain the common occurrence of homosexuality in other species in terms of creation by a magic man who allegedly abhors homosexuality and intended sex to be for procreation only, rather than simply denying that a readily observable phenomenon exists.





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