# How could evolution be disproved? **URL:** \ **Category:** Factual Questions\ **Created:** [July 1, 2005, 6:27pm UTC](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739 "2005-07-01T18:27:48Z")\ **Posts on this page:** 6\ **Page:** 3
**Author:** ![Quercus](https://avatars.discourse-cdn.com/v4/letter/q/7ab992/32.png) [@Quercus](https://boards.straightdope.com/u/Quercus)\ **Post date:** [July 8, 2005, 2:40pm UTC](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739/41 "2005-07-08T14:40:35Z")
For the record, **Finch** , I think you’re consistently one of the clearest writers about evolution on the board. But in the spirit of academic discussion, I agree with the two points made by **ploenast** and **Colibri** ; basically, your first requirement is kind of reduntant. Perhaps my bias is to construct the definition is such a way that it could apply to other systems than known biological ones. In other words, define it so that you could show how selection and evolution could happen with socks in a drawer or something (I haven’t found the perfect quasi-real-world model yet, but still hoping to). I think for some people, that will make it clearer how s & e works, and how inevitible and non-magical it is. If you only want biological models, instead of widgets, use bacteria in a vat. They’re not mating with each other, but most people would consider them a population. In the first case, it’s a vat with penicillin as well as nutrients. The penicillin-resistant bacteria will form a larger and larger proportion of the population, even when there are plenty of nutrients and spaces for all. Or consider a vat with a constant inflow of liquid (and nutrients), and a constant outflow (to a sterilizer). Now the ‘blue’ bacteria with higher reproductive rates will dominate the population, even though there are plenty of resources for all. Aren’t those two situations natural selection producing evolution? > [@](#): > > You can’t have “change in heritable traits” without “changes in gene/allele frequencies”. Nor can you have “changes in gene/allele frequencies” without “change in heritable traits”. Not commonly known to exist in biology, but certainly possible. I suppose you include mitochondrial DNA in the ‘gene/allele’ count. But it’s certainly possible to imagine other components in the maternal egg cell that vary in the population, are passed to all daughter cells of the egg, and provide differing fitnesses. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [July 8, 2005, 4:47pm UTC](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739/42 "2005-07-08T16:47:17Z")
> [@Colibri](#): > > **DF** , I’m surprised that you are disputing this point, since I know you are quite knowledgeable on these topics. But the contention that competition _for resources_ is a _prerequisite_ for natural selection is simply incorrect. I will concede, at this point, that I am perhaps disputing this point simply because once I get a bone-headed idea stuck in my brain, it is difficult to dislodge. My logic here, such as it is, is that survival as the result of fortuitous “pre-adaptations” (these aren’t really exaptations in these cases) isn’t (or shouldn’t be, if I had any say in the matter) a case of natural selection at work. Selection of a sort, to be sure, but adaptation relies on those best suited for _current_ conditions having an advantage, whereas the scenarios presented rely on individuals being better suited for not-yet-present conditions. Thus my insistence that such instances are more driven by luck (or, if you prefer, by mutation) than natural selection. But, I think I’m having difficulty actually coming up with a cogent argument to explain what I mean. I do see the point about bacteria in a petri dish. But, again, I keep coming back to the point wherein the intiial shock of adding some anti-bacterial agent, or changing temperatures or whatever are akin to the initial strike in many extinction scenarios. If it happens that no individuals have the “right” gene to allow them to survive that strike, the population is wiped out. If some individuals do have the correct gene, then those individuals survive, and the population builds from there, with the more resistant individuals forming the new baseline. Certainly, no competition is involved, but there is something there that I can’t articulate that doesn’t “feel” right with respect to natural selection being at work. I know I should know better, but, like I said, once I get a bone-headed idea lodged, it’s difficult to unlodge (remember the one-celled egg discussion from a while back? :p) At any rate, I will concede that competition is not strictly necessary for natural selection. > [@Quercus](#): > > But it’s certainly possible to imagine other components in the maternal egg cell that vary in the population, are passed to all daughter cells of the egg, and provide differing fitnesses. To be honest, I never really cared for the gene-centric definition of evolution in ther first place, so I’m not really sure why I am arguing for it. Feel free to scratch that from my list of issues. Even better, it might be best to dismiss all of my posts within this thread, as I seem to be having some conceptual issues of my own at the moment… ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 8, 2005, 4:52pm UTC](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739/43 "2005-07-08T16:52:12Z")
> [@Darwin's Finch](#): > > Even better, it might be best to dismiss all of my posts within this thread, as I seem to be having some conceptual issues of my own at the moment… Well, I wouldn’t say _that_, since most of what you wrote here is both correct and useful. You just seem to be using “natural selection” in a more restrictive sense than the textbook one. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 8, 2005, 5:20pm UTC](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739/44 "2005-07-08T17:20:39Z")
> [@Colibri](#): > > What I am disputing is _not_ that competition for resources is usually an important factor in natural selection, or a key part of Darwin’s original argument. I am just disagreeing with your statement that competition is _necessary_ for natural selection to take place. It very clearly is not a necessary condition. > > If some individuals survive a period of severe winter weather because of some heritable trait, such as thicker fur, that is natural selection at work, even though there is no competition _for resources_ involved. (Of course there could be competition, if individuals are competing for shelter, but if it is a sparse population and shelter is not a limiting resource it doesn’t have to be.) In fact, one of the very first demonstrations of natural selection at work was based on a study of mortality of small birds (I think it was House Sparrows) during a severe winter storm. But isn’t competition about passing on your genes? You’re “trying” to be the guy or gal who has the baby in the spring. Having thick fur is your way of getting thru the winter in order to be that guy or gal. IOW, to compete agains the guy or gal who doesn’t make it thru the winter. I’m using the active voice here only rhetorically. Obviously, you don’t consciously choose to have thick fur. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 8, 2005, 5:37pm UTC](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739/45 "2005-07-08T17:37:34Z")
> [@John Mace](#): > > But isn’t competition about passing on your genes? You’re “trying” to be the guy or gal who has the baby in the spring. Having thick fur is your way of getting thru the winter in order to be that guy or gal. IOW, to compete agains the guy or gal who doesn’t make it thru the winter. > > I’m using the active voice here only rhetorically. Obviously, you don’t consciously choose to have thick fur. Yes, in a sense organisms are “competing” to pass on their genes to the next generation. However, that’s not the sense in which “competition” is usually used in ecology; in evolution or genetics this kind of “competition” would be called “relative fitness.” In any case, winter survival by means of thicker fur is not competition _for resources_, which is the point I’m objecting to. It’s only competition for resources if it depends on access to shelter which is in short supply (for example), not if it is due to some intrinsic quality of the individual. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [July 8, 2005, 5:49pm UTC](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739/46 "2005-07-08T17:49:36Z")
Got it. Thanks. [Previous page](https://boards.straightdope.com/t/how-could-evolution-be-disproved/310739.md?page=2)