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Natural Selection's Limitations

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Voting Style: Open Point System: 7 Point
Started: 1/22/2015 Category: Science
Updated: 3 years ago Status: Post Voting Period
Viewed: 3,346 times Debate No: 68746
Debate Rounds (4)
Comments (5)
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Resolution: Natural selection is limited to "selecting" certain pre-existing traits and cannot produce novel structures neither by its own power nor with the help of any other natural mechanism such as genetic mutation.

Round 1 - Acceptance

Round 2 - Opening Arguments

Round 3 - Rebuttals Only (No new arguments)

Round 4 - Defense of Arguments Only (No new rebuttals)


I accept the debate and resolution. I'll argue that natural selection is completely capable of exhibiting changes on large a large scale and creating completely new traits within species. The notion that "traits" are selected is a misunderstanding of the nature of evolution.

'Novel structures' - My opponent has clarified this refers to a previously non-existent trait. His example of such being "scales to feathers".

I wish the best of luck to my opponent and assume good faith on his part.
Good luck!
Debate Round No. 1


Quite simply, natural selection describes the process by which organisms' traits are "selected" for their survival benefit. If a trait happens to be advantageous in its particular environment, the trait will remain in the future generations of offspring. If a trait is disadvantageous, then the trait will be "selected" against, thus removing it from the gene pool (

My point of contention arises when evolutionists claim that natural selection somehow contributes to their grand Darwinian theory of evolution. Natural selection in no way supports the idea that all organisms share a common ancestor, nor does it support the "tree of life" model. In order for an original simplified "blueprint" of an organism to evolve into the vast array of "blueprints" of varying complexity and diversity, novel structures derived from new genetic information must be created by some natural mechanism. No mechanism has yet been discovered which can conclusively satisfy this requirement. Natural selection, in fact, works against the evolution hypothesis in that it ultimately works to remove genetic information from a gene pool, not add to it. Natural selection is not a creative process nor does it produce anything new; it merely selects from pre-existing genes (

Through sexual reproduction, we observe a loss of genetic information in that the offspring only inherits half of the genes from mom and half of the genes from dad. For example, consider a human couple with only one child, where the mother had the AB blood group (meaning that she has both A and B alleles) and the father had the O blood group (both alleles are O and recessive). So the child would have either AO or BO alleles, so either the A or the B allele must be missing from the child’s genetic information. Thus, the child could not have the AB blood group, but would have either the A or the B blood group respectively. Consider the following simplistic example:

Dog fur illustration

In the above illustration we see that the genes for short and medium fur have been lost. In order for these traits to be once again exhibited in a population, they must be reintroduced through dogs which have these genes; the population of dogs cannot recreate these traits on their own. Herein lies the limitations to natural selection: as an unintelligent natural process, it cannot create new genetic information; it only works to select from already existing genes.

I await your opening argument. . .


Basic Natural Selection

Pro took some burden off me by accepting the validity and providing an example of the basic evolutionary process to an extent, which indeed demonstrates changes in traits. My assumption is that he's going to argue on the basis of what's considered an "additional" trait and an implied lack of observation of gain-of-function mutations. Additional traits can't be differentiated from preexisting traits based on the effect alone, however. A change in an animals colouration is not necessarily equivalent to a single gene change in the creatures genome unless evolution has played a part in optimising the process (more on this later), but often multiple gene's which all have to change in the right way. This common objection some have is one of the core points I'm going to be addressing.

I'd like to use a more practical and explanatory example natural selection as my main example of this in play (1). The DNA of mice had changed in multiple places in order for the mice to adapt to a change in environment. The colour change of the rocks they populated caused mice to be seen easily by predators. When a darker mouse arose, it had an advantage and was able to reproduce more dark mice. Natural selection plays little direct role in the mutation, but the selection of the mutation itself - though natural selection can also be considered to have affected this mutation a long time ago.

Mutations we observe aren't usually without limitation. Creatures very rarely mutate without a leg, or with extra toes, etc. which is also due to natural selection. More specifically, it's due to the way certain genes grow stronger through repeated generations. What I'll refer to as "base genes" may occur through many thousands of generations of particular genes, in which any creature without those genes would never survive - and possibly may never even be capable of being born - the importance of survival before birth as part of natural selection is often hugely underestimated (sperm also need to survive).


Traits cover a huge amount of properties in living things. Anything about living creatures can be considered traits - the difference between small changes and a large ones can be trivial and subjective. Similar traits can form bigger ones which we recognise more clearly. With mice changing colour, the gene changes to do so could've happened in smaller increments, but once again this is an example of mutations becoming more fixed as a species becomes more advanced. In the simplest creatures, they're more likely to completely mutate into something unsuccessful because their "base genes" haven't had time to form. This can be observed in the E. Coli experiment (2) - many trials had to take place which could both end up resulting in dead populations and ones that evolved to survive testing conditions. Here we see function increases in the mutations, thanks to the simplicity of the bacteria. They haven't had the evolutionary progress to have established genes, used or unused, to cope with the citric acid, so the only way for a strain to survive is to acquire new genes and traits, which one did, and began using the acid as a carbon source (3). Dangers come and go, but most repeat themselves, so it's natural for most species' by now to already have an optimal genome size (too large, and they require more energy sources, which is bad) and many genes that aren't used, but could be to overcome a danger in future generations should that danger occur.

The experiment shows a new trait forming by the processs of duplication and rearrangement. Information already existent was duplicated, then rearranged to create a more complex set, capable of being further mutated to evolve a new ability. There are other examples of new traits forming for survival and becoming a consistent part of the gene pool, some of which have caused insects to become immune to various pesticides (4). Immune systems of humans and mammals adapt during their lifetimes and the resulting changes can be passed down to offspring - not only the initial reproduction, but for even longer through other means such as breastfeeding, which help babies gain various immunities to colds and flus. This makes up for the long lifespan when compared to the smaller creatures which are capable of adapting much more quickly through generations by reproduction alone, otherwise humans and other mammals would be much weaker than small organisms when it comes to dieseases and wouldn't continue to survive.

Traits can also include psychological and social behaviours, which can be gained as well as lost or changed, and are dependent on evolution of the brain. Another valued trait as Pro highlights are feathers, and theories are already being worked on precicely to explain these changes (5). It's obviously difficult to say anything for sure because of the unpredictability of mutations and the limited capability of studying undocumented past events, so it's more efficient to study evolution going on today. The difficulty there is that the species' today are now the result of millions of years of evolution and natural selection, and are less likely to need drastic changes in their genomes now. Mutation will always continue to happen, but natural selection becomes less effective in causing change when species become more effective at survival. Once they're at their most effective, a genetic mutation will more likey be bad than good and won't be kept around for long.

Reapplication of Natural Selection

Natural selection solves some very underestimated problems and is more than just an explanation of evolution, but a theoretical process which can be applied to anything, and has. In fact, it is currently deemed an essential process for the progress of AI. So, the easiest way to prove natural selections effectiveness is to see an example of it in simulation.

Polyworld is an open-source program intended to evolve artificial intelligence autonomously through natural selection (6). It uses a neural net which simulates how the brain works - there's no true answer to any input. For example, inserting 1 may output 0.3 for no reason (in Polyworld, the initial state of the neural net is based on a genome given to a creature on it's creation), and it has no way of knowing whether that is a correct result - it can also use sight as an input, but has no direct way of associating the input with anything. In it's earliest stage, an artificial lifeform is given a basic set of behaviours, and their use is determined by this neural net. The creatures usually require energy from food to continue surviving, and they can reproduce and pass their genome down, which affects the descendants neural net. The first creature may do nothing but go in circles or in a straight line, depending on the initial neural net. The second takes after it's parent and produce similar outputs as behaviours. Over time, the creatures grow and grow in complexity and begin actually exhibiting lifelike behaviours (7). They start using their vision input without being programmed to, they detect other creatures and food, and can eat either (8). This is all because of natural selection - it's not programmed or driven in any way, but simple logic dictates that surviving methods will continue surviving.

This example alone directly addresses the main resolution, which questions natural selections effectiveness. Natural selection need not imply natural world evolution. Natural selection is merely a theory of logic based on how life works.


Debate Round No. 2


Your first claim in round 1 is a bit confusing. You said, "The notion that 'traits' are selected is a misunderstanding of the nature of evolution." Is not natural selection a primary mechanism for evolutionary change? And does not natural selection "select" traits based on their survival benefit? To deny this is to deny what every biology textbook teaches concerning natural selection. Your first perplexing assertion aside, below I shall be addressing your claims as space and time permit.
Rebuttal and Addressal of Con's Opening Arguments
You begin by stating that I provided an example which "demonstrates changes in traits." No, what I did what provide an example of natural selection, showing that it merely works to select from what is already available in the gene pool of a population.
You go on to say, "My assumption is that he's going to argue on the basis of what's considered an 'additional' trait and an implied lack of observation of gain-of-function mutations." Your assumptions would be wrong then. I have already made my case demonstrating that natural selection only works to select from pre-existing traits. Why would I need to semantically argue about the term "additional?" It seems quite unnecessary to define this simple word. The creation of a trait that was not previously made available from an organism's genome would be the minimum requirement necessary to satisfy the resolution. Also, why would I argue about the functionality of mutations? I do not see how this plays any role in this debate. A gained function is not necessarily the same thing as a gain of a novel structure or trait. Yes, mutations through duplication, recombination, etc. can provide variety within a species, but this variety is limited to the informational content of the species gene pool.

From that egregious statement you seem to go off on a tangent and propose your main addressal shall be toward what you deem as a :"common objection some have." Why would you argue against an objection I have not made? Seems rather pointless, but I digress.

I agree with most of your next paragraph concerning the mouse example, with one important exception. You seem to equate preexisting traits with mutations, or you at least seem to be implying that these traits have been created via mutation. Now are you arguing that mutations alone produce novel traits and not natural selection?

Your following paragraph concerning mutations seems negligible to me, so for sake of time I shall skip over it.

You begin this part of your argument, under the heading "Traits," by making a statement concerning the trivialness in the difference between "large" and "small." While I think I somewhat agree with what I believe you are saying, describing traits in terms of quantity or quality really does not help either of our cases. The issue is really quite simple: can the mechanism of natural selection, either alone or in conjunction with some other mechanism, produce novel structures or not?

What I found most disconcerting was the fact that your entire argument here seemed to rest solely on the power of genetic mutations and not natural selection. While I disagree with most of what you claimed concerning the potential for mutations to produce novel structures through duplication and recombination, it should be seriously noted that this debate is concerning the power of natural selection, not mutation alone. If you wish to incorporate the mechanism of genetic mutation into your argument, you must do so in a way which involves natural selection as a co-contributor to the production of novel structures. I will address the issue of gain-of-information mutations at the end of this round below.

There is really not much to say in response to your last few paragraphs concerning Polyworld and natural selection. I assumed it was understood that this debate was concerning biological organisms not computer simulations. I see no merit in such endeavors, and even given the veracity of your claims concerning Polyworld, which is in serious question, it remains unuseful in this debate; you have yet to address the resolution.

Your last claim is telling to say the least. You say, "Natural selection is merely a theory of logic based on how life works." So you have effectively moved the debate, arbitrarily I might add, from the realm of natural processes to the realm of philosophy. Oh boy. . .

The Issue of Gain-of-Information Mutations

I should begin by pointing out that even if mutations were able aid in the formation of novel structures, it would still not help Con's case unless he were able to demonstrate the vital role of natural selection in relation to the production of previously non-existent traits. With that said, allow me to demonstrate why even if the resolution dealt strictly with mutations and not natural selection, my opponent would still be in error.

I should make it clear that I do believe mutations can create new traits within a species, but in none of these observed instances is the theory of evolution helped.

Consider the example you gave of E. coli digesting citrate. The the popularist treatments of this research (e.g. in New Scientist) give the impression that the E. coli developed the ability to metabolize citrate, whereas it supposedly could not do so before. However, this is clearly not the case, since the Krebs cycle generates and utilizes citrate in its normal oxidative metabolism of glucose and other carbohydrates. Furthermore, E. coli is normally capable of utilizing citrate as an energy source under anaerobic conditions, with a whole suite of genes involved in its fermentation. This includes a citrate transporter gene that codes for a transporter protein embedded in the cell wall that takes citrate into the cell. This suite of genes (operon) is normally only activated under anaerobic conditions (

Gain-of -information mutations can be a tricky subject as one must determine what merits the title "new information." When considering this issue, we must keep in mind that mutations are entirely random ( The few examples given by evolutionists as supposed examples of novel structures being formed through mutation fall short of their claims as we clearly only ever see a degradation of original informational content, not the addition of new, viable code. It is very illogical to even imagine such a random and thoughtless process as genetic mutations producing every complex structure exhibited in biology.

If we look beyond the term "information" and recognize the true issue at hand, we can readily see that evolution's required mechanism for producing every structure in biology is not to be found in genetic mutation. The development of new functions is the only thing important for evolution. We are not talking about small functional changes, but radical ones. Some organisms had to learn how to convert sugars to energy. Another had to learn how to take sunlight and turn it into sugars. Another had to learn how to take light and turn it into an interpretable image in the brain. These are not simple things, but amazing processes that involve multiple steps; and functions that involve circular and/or ultra-complex pathways will be selected away before they have a chance to develop into a working system. Saying a gene can be copied and then used to prototype a new function is not what evolution requires, for this cannot account for radically new functionality. Thus, gene duplication cannot answer the most fundamental questions about evolutionary history. Likewise, none of the common modes of mutation (random letter changes, inversions, deletions, etc.) have the ability to do what evolution requires.
In conclusion, I must say that Con has yet to address the resolution of this debate. On to you Con. . .



NS: Natural Selection
My claim was merely that our idea of a 'trait' is subject to interpretation, where biology goes into more complex steps and doesn't recognise 'traits' but what causes them, while we consider things we see a trait and don't think about what goes on in the background. NS doesn't "select" traits as a force, but is merely a concept explaining how certain changes will likely die out. Our interpretation makes NS appear more "in control" than it is as we look to it to explain complexities. I'm not arguing with biology, but rather how one may interpret data to make sense of it, which may in turn create an over-complexity in one's mind.

Your first rebuttal is an example of this. Your first example shows a change in traits, with traits being geared towards the colour of beetles. Your example starts with orange beetles, and you seem to be claiming that if it didn't, there would have never been any, and the species would become extinct. This is an assumptoin and not the case with the real-world example I cited in source 1 of my first argument. The dark mice occured not by selective breeding but mutation. There were no dark mice living on the light rock before the environment changed as they would've been caught by predators. The light colour occured due to a mutation in a gene sequence which was favourable for getting past NS. What's more, they didn't change colour completely - their bellies, being that they faced the ground, remained lightly coloured.

My assumption was mostly correct, unless you accept that gain-of-function mutations happen, which is true. This mean traits arise which didn't exist, which means you accept your own resolution as false. The thing I didn't realise is you seem to fully deny your beetles the possibility of changes occurring, ever. You understand that NS only filters out bad mutations (which I added on that this can cause mutation bias in the future, aiding good mutations), so the only thing you're really in disagreement with is mutation itself. The genomes of your dogs don't loose a "long fur" gene, they have their fur genes altered so the growth of fur is limited. Energy and time are naturally part of the DNA of all species. We have genes, but there also exists genes to control those genes, as well as genes to control further mutations, and who knows what else left to discover after only 20 years of research. Gene mutations can be biased as well as recessive (1), NS won't usually act towards getting rid of something unused because there's no effect for NS to act on, and instead it's kept and genetic switches are used to disable functions, so whether loss-of-information mutations are even that frequent is up for debate.
Your examples include sexual reproduction, and sexual reproduction is also heavily affected by genes and NS. Animals will instinctively opt for genetic variety, which further increases the changes of the mutations being more random and unlike either parent. These instincts may be exacerbated by NS for the reasons I already highlighted, as the environment and how often it changes can demand more or less evolution through NS.
"Yes, mutations through duplication, recombination, etc..."

Not true, I covered this. Mutations aren't limited to preexisting information, this is widely known in genetics. Mutations can both be inherited as well as random. You can't deny this without arguing the semantics of what can be considered an additional trait, because the documentary of observed mice fur colour evolution I cited demonstrates this. NS had no reason to keep dark mice before, yet they still arose once again through mutation. It used preexisting genes, which were different or disabled, and there's no way to determine the gene, but by mutating the gene randomly it would eventually pass the NS test. A genome can't possibly store the entire gene pool of it's species somewhere, but what it can do is use other parts of the genetic code to randomly mutate in offspring. You should really explain more why you think limitations in mutation exist.

Mutations alone do produce the traits, but NS plays the critical role of selecting them, and thus influencing the bias of future mutations which can produce more traits, as per your resolution, saying NS with the help of genetic mutations couldn't produce previously nonexistant traits, which I've shown is untrue. All of what I said is important to disproving the resolution. That's what my final opening paragraph further explains. It seems ridiculous to focus on NS when it is so simple and your first argument basically accepted it, so I focused on mutation helping the traits become part of the species. Without the random mutations, evolution would be a board game with no dice. NS is the set of rules for deciding the winner.
You defined 'novel structures' as previously nonexistent traits, which again, I've highlighted do occur as the first point of my arguments. With the help of mutation, I've explained how NS is capable of producing traits, and you agree to the trivialness of large or small traits, therefore I've addressed the resolution fully. You're concerned over my focus on mutations, but you agreed it can help the NS role in evolution. I explained how NS also helps affect mutation processes over time. NS plays a role in all parts of evolution, as whatever fails doesn't take part in future mutations, so mutations are mutually aided by NS that took place before it.

"I assumed it was understood that this debate was concerning biological organisms not computer simulations"
Then you've not paid enough attention to my points or sources explaining how Polyworld works or how NS is merely a process. It's based on biological organisms, and computers have long been used to simulate natural processes. You've not given a reason why behaviour traits can't count. Simulations are imitations of real-world processes and systems. Showing an accurate working simulation of NS, mutations and neural networking show how the real-world processes behave (successfully).
I addressed the misunderstandings expressed in your first 'Issue of Gain-of-Information Mutations' paragraph, as you seem to have missed my points binding mutations to natural selection.

"I do believe mutations can create new traits within a species, but in none of these observed instances is the theory of evolution helped"
The resolution says nothing about "helping" the theory of evolution, the theory of evolution is already a proven fact you've not argued against in this debate. Your resolution only brought the parts NS plays in new traits forming into question. I've made many points binding NS to mutations, which your resolution stated could help NS. Therefore this statement accepts my other points which refute the resolution, with the only point left unaccepted being the binding of NS to mutation, which I hope you address better in the next round.

Mutations (causes) happen constantly, NS favors them based on traits (effects) they produce. NS helps favour causes (mutations) based on effects (traits), and future mutations will be based on what was favoured too. This doesn't put the previous causes on a blacklist, but they will be less common. NS has altered all of these things, it depends on traits, traits depend on the mutations, mutations depend on what NS favoured previously, what NS favours depends on traits, etc.

I'm sure I addressed the resolution well, counting the arguments you put forth which focused on the same NS process, which alone is an argument for NS, assuming the rest of evolution works normally. I explained how genetic mutation and NS can result in wide amounts of patterns and why doubts of its extent can be misguided. I've covered different angles and aspects of the processes involved as is within reason and shown there are simpler ways of thinking about the complications you claim exist.
Debate Round No. 3


In this round we shall be defending our arguments. I ask Con not to posit any further rebuttals as I would be unable to respond to them in this debate as this is the final round.

My Defense of Natural Selection's Limitations

The resolution clearly concerns the power of natural selection to produce novel structures or traits. Obviously mutations can produce new traits, but such changes are limited and in no way help the grand theory of evolution. My opponent has chosen to support his argument purely from genetic mutations and has not incorporated natural selection in such a way that would address the resolution. Never did Con show how natural selection could create new traits, merely, he stated that natural selection guides mutations. If mutations create genes, then natural selection only selects them, thus my argument stands.

In further considering the power of natural selection, we must recognize that the term describes environmental forces which allow a population to survive or not. Artificial dog breeding is a great example of natural selection.

Existing dog breeds have a particular set of traits derived from their genomes as well as the potential for other traits which, though they may not be displayed in that particular breed's phenotype, are nevertheless available in their genomes. From the blueprint of two different breeds, breeders can select for the most desirable traits, as well as unknowingly select for some that are not so desirable, and create a new breed. Think about this carefully; now if Con is correct, this should support his position, and if I am right, this should support my position. But how can two opposite views be supported by the same example? Clearly one of us is missing something in their understanding of what is taking place in the production of a new breed of dog. Now if we truly investigate what is taking place, we will find that, while a new variation of dog has been created, it has merely utilized the genes from its parents to display the traits it does, it has not created a truly new trait. It still has fur, four legs, two eyes, one nose, etc. And to further drive home the idea that nothing new has been created, just a mixing of traits, imagine if a dog was born with two heads.

Woof woof!

Yes this would be due to genetic mutation, but the principle remains the same. The parents did not have two heads, so you might claim a new trait has been produced (via mutation not selection), but really the information to build a head was already available, mutations have merely caused the cells to grow a secondary head. What we truly witness in the change between parent and offspring, even given millions of imagined years, is the rearrangement, removal and degradation of genetic information (

Beyond the fact that nothing new is created via natural selection, it is demonstrably true that natural selection eliminates genetic information, even beyond the elimination through sexual reproduction. Consider the following illustration:

Artificial selection depletes information

Above we see that the last generation of dogs has lost the genetic information which limits the growth of the dog. In this hypothetical scenario, nature has selected against the small and medium dogs and only the large dogs remain. Thus we see a downhill process for evolution. In the above illustration a single gene pair is shown under each dog as coming in two possible forms. One form of the gene (S) carries instructions for large size, the other (s) for small size. In row 1, we start with medium-sized animals (Ss) interbreeding. Each of the offspring of these dogs can get one of either gene from each parent to make up their two genes. In row 2, we see that the resultant offspring can have either large (SS), medium (Ss) or small (ss) size. But let’s suppose that breeders want large dogs. They would select the largest dogs in the next generation to breed. Thus only the big dogs pass on genes to the next generation (line 3). So from then on, all the dogs will be a new, large variety. This is artificial selection, but natural selection would work on the same principle, if large dogs would do better in their environment. Note that:
  1. They are now adapted to their environment, in this case breeders who want big dogs.
  2. They are now more specialized than their ancestors on row 1.
  3. This has occurred through artificial selection, and could have occurred through natural selection.
  4. There have been no new genes added
  5. In fact, genes have been lost from the population—i.e. there has been a loss of genetic information, the opposite of what microbe-to-man evolution needs in order to be credible.
  6. Not only genes for smallness were lost, but any other genes these small dogs carried. They may have had genes for endurance, strong sense of smell, and other things, but they are lost from the population. Genes on their own are not selected; it’s the whole creature and all the genes they carried.
  7. Now the population is less able to adapt to future environmental changes—if small dogs became fashionable, or would perform better in some environment, they could not be bred from this population. They are also genetically impoverished since they lack the good genes that happened to be carried by the small dogs.


I posted this debate to magnify the fallacy of those who claim that natural selection can in fact create new traits. We hear about it on public television shows and read about it on popular nature articles and news posts online. Worst of all we hear it in school, and children today are being deceived by a bait-and-switch deception. They are told natural selection helps organisms in the formation of a new trait, but are then shown examples such as dog breeding which clearly show a rearrangement, degeneration, and loss of genetic information. In this debate I have remained on point with the resolution and simply addressed the failure of natural selection to actually produce new traits. Con has argued from evolution only and has not tied his argument in with natural selection. Since Con did not address the resolution in his argument based on mutation, I did not offer a thorough rebuttal to his claims, rather I merely pointed out the easily seen detrimental problem of random genetic errors, even ones which duplicate or recombine genetic code, producing viable blueprint for novel structures. If Con would like to have a debate purely on the power of genetic mutation I would be glad to do so, but as for this debate it is clear that Con has lost since he did not address the resolution, and if he formulates a whole new argument in the next round he will have violated the terms of the debate and warranted a loss.



NS = Natural Selection

Pro has stuck to the same points throughout this debate and though I've addressed each of them, Pro hasn't actually rebutted my arguments. Pro asserts that I'm not defending NS, which is completely misguided, and I feel that Pro is either ignoring or failing to understand my points and has failed to address them.
NS indeed acts like a filtering process to remove bad traits from the gene pool, which is hugely important to evolutions development of new species. As I pointed out, it also affects future mutation bias. This point has been left completely unaddressed by Pro.

The diagrams Pro uses are quite a naive representation of NS if taken on face value. If the number of creatures of a species in real life were as limited as Pro's illustrations make out and we only observing a generation or two, then it wouldn't be surprising for the species to remain completely the same or even go exstinct.
By having 1000 creatures, we can easily encounter beneficial mutations occuring, which Pro's illustrations pretend don't exist, even though I've shown they do and Pro has agreed to that. Pro's dog illustration assumes animals only sort of "blend" when they reproduce, taking 50% DNA of each parent, when this is known to be completely false. We could assume they take a lousy 49% DNA of each parent (completely dependent on the species and its evolution), and we'd still be left with a huge amount of genes to randomly mutate - and they'd mutate based on the parents genetic code for mutation. Assume there's an unfavourable 50,000 genes (also dependent on species - they'd have way more) and worse still, 0.5% control reproductive mutation (250 genes) there's about a 0.02% chance of each creature mutating genes that control further mutations. This would be insignificant without NS, but the most successful patterns will start to either dominate the population or branch off into a separate genus.

I don't feel much need to defend my arguments again, because so few of them have been directly contended with any factual in-depth information, merely arguments from ignorance and baseless accusations. So I will summarise the points I have made and the contentions Pro has made.

Mice demonstrated the ability to produce a change in trait, producing dark fur in a population full of mice with light fur

Pro hasn't addressed this directly, despite me mentioning it heavily in round 2 & 3, providing sources in the former. Unlike Pro's basic interpretations of NS, new traits appear to have formed, most likely aided by mutation bias as a result of NS. Not only do the mice have the fur colour themselves, but have shown the ability to consistently reproduce mice with the same fur colour, showing that NS helps assure these changes do not happen. Pro's examples assume the light fur colour would just "disappear", yet where did the dark colour come from originally?

E. Coli experiment observed the evolution of Cit+ E. Coli to metabolize citrate in the presence of oxygen

Pro outright denied this as a new trait. I prediceted disagreement with what's considered a new trait. But the empirically tested fact is that the E. Coli species can't grow on citrate while oxygen is present. The trait eventually reached through NS took many years of evolution, and about 31,500 generations for it to happen, with many other less substantial variations occuring on the way. This shows what I highlighted previously, that certain mutations are rare, and mutation bias from previous NS plays a huge role in evolution. By comparison, the evolution of mice happened a lot faster, because a change in fur colour is a less rare mutation as it is more likely to be required. This shows mutation bias correlating with the most likely NS patterns. Mutations can't predict what is beneficial, so they play the odds from the historical data of NS. This created a whole new species. It's only a "pre-existing" trait if you consider it to have already developed that trait in the past. But unlike Pro's diagrams, the NS of a beetles colour or dogs fur length doesn't mean the traits that died out won't return, and when they do, they may be not be the same, and since it had to duplicate and rearrange for that to happen, it'd be luck for it to re-acquire a previous trait by change when a new one could do. There's no direct memory of previous traits without NS to build up the most benificial genetic code.

Dog breeds that can rapidly change their most basic genes in just a couple of generations is not a good comparison to actual evolution of species. It is, however, a good example of basic mutations and how people who don't understand evolution tend to take examples on surface-level. But this comparison is no better than comparing the inheritance of human eye colour through generations. It's a good example of a lack of NS, as NS not really affecting these changes means they're free to happen often, with little chance to be a detrement, and little chance to be beneficial.

Real evolutionary leaps happen under intense pressure. With the mice, they didn't change fur colour right away, because that would've been an immediate detrement. Only under the pressure of NS did the population eventually become lighter. Dog breeding does not rely on NS, it tends to rely largely on how cute people find the puppies. It'd take a lot of dog breeding, along with constant genetic analysis over hundreds of thousands of years, to breed a dog with an extra tail. We could plan ahead and know exactly what genetic changes needed to be made and purposely breed towards that, but it'd still take a very long time, especially due to a dogs lifespan and inability to procreate early in life.
A dog with two heads in the wild is unlikely to survive and reproduce. NS ensures this doesn't happen, manifesting in mutation bias. I've never even heard of a dog being born with two heads in fact, so that seems completely irrelevant.

Psychological & social behaviours count

Pro never addressed the relevance of psychological & social behaviours being traits selected by NS.

Polyworld evolution simulation

Pro rejects, possibly out of lack of understanding, the comparison of NS in the real-world to the simulation of it on a computer, but didn't provide much reasoning for doing so. I maintain that Polyworld is a good example of the power of NS specifically. Without it, the creatures wouldn't actually make any progress, no matter how accurate the mutations are compared to real-life.


Pro hasn't put forth many clear arguments of his own, mainly contended mine with little actual depth or detail to rebut. Pro wishes to excuse this by accusing me of not actually addressing NS, which is so wrong that I had to make it an acronym to reduce character count, and Pro didn't go into enough depth to back this claim either.

Overall it seems to be coming down to semantics on whether NS "produces" the trait versus mutation, however Pro's resolution stated that it was fine to include mutations in the defense of NS. However mutations don't produce lasting traits in species, but rather individual creatures. It's only by applying NS that particular traits actually become a part of a species rather than just the one creature. One without the other wouldn't be effective, so it's easy to argue that only one does the job, but wrong.

Since I have made the most thorough arguments, with points actually backed up by, rather than based on, the sources I've cited, which are scientific and real-life examples rather than oversimplified diagrams biased towards asserting creationist theories, and haven't had any of my points addressed thoroughly by my opponent, I urge people to recognise that I have quite clearly refuted the resolution, showing that NS, in combination with other natural mechanisms, is indeed capable of producing new traits in a species, and that it not only selects pre-existing traits, but encourages the mutations which produce traits in a creature.
Debate Round No. 4
5 comments have been posted on this debate. Showing 1 through 5 records.
Posted by creationtruth 3 years ago
In my conclusion I meant to say that Con has only argued from mutation, not evolution. lol
Posted by TheAnonymousTipster 3 years ago
Sorry for my brevity towards the end there, ran out of characters pretty fast haha...
Posted by creationtruth 3 years ago
By novel structure I mean a trait which was previously non-existent (e.g. scales to feathers).
Posted by creationtruth 3 years ago
TheAnonymousTipster - That was quick!
Posted by TheAnonymousTipster 3 years ago
I accept the debate and resolution. I'll argue that natural selection is completely capable of exhibiting changes on large a large scale and creating completely new traits within species. The notion that "traits" are selected is a misunderstanding of the nature of evolution.

I do however wish to clarify your definition of "novel structures" in the resolution. I assume you mean an evolutionary change that can be apparent as a feature of an animal.
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