# Can a Species Win/Lose the Evolutionary Arms Race? **URL:** \ **Category:** Factual Questions\ **Created:** [September 2, 2014, 5:32pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270 "2014-09-02T17:32:59Z")\ **Posts on this page:** 18\ **Page:** 2
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [September 3, 2014, 6:08pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/21 "2014-09-03T18:08:36Z")
> [@HoneyBadgerDC](#): > > The lancehead viper off the coast of Brazil may be a good case study. I believe he has developed a very quick acting poison to stop birds very quickly. I would imagine before this happened he was brought to the verge of extinction. They are so numerous now i would imagine any resident populations of birds that feed in the brush will eventually be threatened. OK, so, let’s take the development of venom as a possibility. Venom could certainly make a jump in toxicity in a single evolutionary step. However, I would argue that going from “sort of venomous” to “really venomous” is unlikely to make a huge difference in the predator/prey relationship. In a situation like that, the prey’s main defense isn’t going to involve being resistant to the venom; it’ll be in avoiding the predator, through physical means (flight, speed) or behavioral (hiding). I can’t imagine a situation where those animals that get caught and envenomated, and then escape to survive another day, would make up a significant proportion of the population. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [September 3, 2014, 6:15pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/22 "2014-09-03T18:15:11Z")
> [@Smeghead](#): > > OK, so, let’s take the development of venom as a possibility. Venom could certainly make a jump in toxicity in a single evolutionary step. However, I would argue that going from “sort of venomous” to “really venomous” is unlikely to make a huge difference in the predator/prey relationship. In a situation like that, the prey’s main defense isn’t going to involve being resistant to the venom; it’ll be in avoiding the predator, through physical means (flight, speed) or behavioral (hiding). I can’t imagine a situation where those animals that get caught and envenomated, and then escape to survive another day, would make up a significant proportion of the population. I believe what was happening was that the snakes venom would kill the bird but the snake that killed the bird would not reap the benefits. His posion had to be strong enough to stop the bird in its tracks. A snake cannot afford to waist protien rich venom. Most likley the birds would need to get faster reflexes because the snakes have become so successful and numerous that they are in virtually every bush. I see this relationship possibly collapsing in the future. My money would be on the birds winning this race. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [September 3, 2014, 7:42pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/23 "2014-09-03T19:42:17Z")
> [@HoneyBadgerDC](#): > > I believe what was happening was that the snakes venom would kill the bird but the snake that killed the bird would not reap the benefits. His posion had to be strong enough to stop the bird in its tracks. A snake cannot afford to waist protien rich venom. Most likley the birds would need to get faster reflexes because the snakes have become so successful and numerous that they are in virtually every bush. I see this relationship possibly collapsing in the future. My money would be on the birds winning this race. From the point of view of the bird, though, it doesn’t make a difference whether or not it gets eaten. It’s still dead. So increasing the toxicity of the venom a notch or three isn’t going to suddenly drive the birds into extinction, which is the whole point of this thread. ---
**Author:** ![Fotheringay-Phipps](https://avatars.discourse-cdn.com/v4/letter/f/d9b06d/32.png) [@Fotheringay-Phipps](https://boards.straightdope.com/u/Fotheringay-Phipps)\ **Post date:** [September 3, 2014, 7:59pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/24 "2014-09-03T19:59:19Z")
> [@Quercus](#): > > I think it’s very unlikely to happen with a change in a continuous, physical characteristic, such as strength or speed. It’s just too difficult to make a sudden change in those kind of characteristics without significantly hurting the animal in some other way. Why qualify with “sudden”? > [@Colibri](#): > > See my post #9. It is well established evolutionary theory. You in fact refer to it in the title of the OP. It’s implicit in the evolutionary arms race concept that if one species fails to keep up it will become extinct. It’s implicit that … if. My question was whether. > [@Colibri](#): > > It might also be mentioned that fossil faunas almost always include several predator species and several prey species. In modern faunas, for example, lions prey on zebras, wildebeest, and many other species, while zebras are preyed on not only by lions but by hyenas and wild dogs. Linking an extinction to a change in a single other species is going to be difficult unless it is an extremely specialized relationship. Sperm whales and squid is an example that comes to mind. I believe there are also a lot of parasites who specialize in certain species. But in general, the impact of the decline or possible extinction of a species is frequently described in terms of its impact on other species. So it’s not like others can just step in to fill the void and leave no impact. > [@Smeghead](#): > > OK, so, let’s take the development of venom as a possibility. Venom could certainly make a jump in toxicity in a single evolutionary step. However, I would argue that going from “sort of venomous” to “really venomous” is unlikely to make a huge difference in the predator/prey relationship. In a situation like that, the prey’s main defense isn’t going to involve being resistant to the venom; it’ll be in avoiding the predator, through physical means (flight, speed) or behavioral (hiding). I can’t imagine a situation where those animals that get caught and envenomated, and then escape to survive another day, would make up a significant proportion of the population. There are also cases - as cited above - where the prey is the one with the venom. So being immune is crucial to the predator. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [September 3, 2014, 9:03pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/25 "2014-09-03T21:03:31Z")
> [@Fotheringay-Phipps](#): > > Why qualify with “sudden”? It would almost need to be sudden, otherwise the other species would have time to adapt. > [@](#): > > Sperm whales and squid is an example that comes to mind. I believe there are also a lot of parasites who specialize in certain species. But could we tell just from the fossil record that sperm whales and squid have such an exclusive relationship? Highly doubtful. Given the length of evolutionary time scales, the story would have to at least partially told in the fossil record. > [@](#): > > There are also cases - as cited above - where the prey is the one with the venom. So being immune is crucial to the predator. Granted. I don’t see that that changes any of the conclusions made so far. ---
**Author:** ![Fotheringay-Phipps](https://avatars.discourse-cdn.com/v4/letter/f/d9b06d/32.png) [@Fotheringay-Phipps](https://boards.straightdope.com/u/Fotheringay-Phipps)\ **Post date:** [September 3, 2014, 9:22pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/26 "2014-09-03T21:22:39Z")
> [@Smeghead](#): > > It would almost need to be sudden, otherwise the other species would have time to adapt. But that’s assuming that the other species is able to adapt given enough time. Suppose one species had genes which adapted faster, for whatever reason, then the other would slowly fall further and further behind over time. > [@](#): > > But could we tell just from the fossil record that sperm whales and squid have such an exclusive relationship? Highly doubtful. Given the length of evolutionary time scales, the story would have to at least partially told in the fossil record. I’m not sure what you’re saying here. I’m not saying anything should be documented in the fossil record. I’m merely citing sperm whales and squid as an example of species that have a close predator/prey relationship, such that if adaptations to one outstripped adaptations to the other it might impact the survival of the species. Whether such a thing could be documented is another issue entirely. > [@](#): > > Granted. I don’t see that that changes any of the conclusions made so far. It relates to the specific point it was addressed to. You were questioning whether venom resistance is all that big a deal, and I was observing that your point applied to the prey only and not to the predator. Because a predator would typically need venom resistance 100% of the time or close to it. ---
**Author:** ![Ornery\_Bob](https://avatars.discourse-cdn.com/v4/letter/o/da6949/32.png) [@Ornery\_Bob](https://boards.straightdope.com/u/Ornery_Bob)\ **Post date:** [September 4, 2014, 5:36am UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/27 "2014-09-04T05:36:16Z")
_Suppose one species had genes which adapted faster, for whatever reason, then the other would slowly fall further and further behind over time._ Genes don’t adapt; they mutate randomly. Its the environment and ecology that determine if that mutation is an adaptation. The mutations keep on coming, regardless if they end up being adaptations. If a faster rat comes along, it creates selection pressure for faster cats. Nobody wins because their “adaptations” are linked. ---
**Author:** ![dracoi](https://avatars.discourse-cdn.com/v4/letter/d/90db22/32.png) [@dracoi](https://boards.straightdope.com/u/dracoi)\ **Post date:** [September 4, 2014, 6:26pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/28 "2014-09-04T18:26:59Z")
> [@Ornery\_Bob](#): > > _Suppose one species had genes which adapted faster, for whatever reason, then the other would slowly fall further and further behind over time._ > > Genes don’t adapt; they mutate randomly. Its the environment and ecology that determine if that mutation is an adaptation. The mutations keep on coming, regardless if they end up being adaptations. > > If a faster rat comes along, it creates selection pressure for faster cats. Nobody wins because their “adaptations” are linked. Well… I’m not sure this line of reasoning can stand up in all cases. For example, insects are largely limited in size because of limitations in their skeletal and circulatory systems. So let’s say that a beetle and a mouse are both experiencing selection for larger size. You’d have a short period where both can scale up using their existing organ structure (the “arms race”) but the beetle will quickly reach a maximum size. The beetle can’t scale up to rat size because it will suffocate without some novel new oxygen-exchange system. On the other hand, a mouse (under continuous selective pressure for size) can scale up quite nicely until you have a capybara (using another rodent as an example) or an elephant or whale (using other mammals as an example). There just aren’t any ten-ton beetles anywhere, ever, and there never will be until they reboot their skeletal and respiratory systems. Relating this to the OP’s example, the selective pressure is going to happen pretty quickly (a few hundred generations, maybe; look at selective breeding in domestic animals). You get larger, larger, larger until you hit some limit in your environment or physiology that counters the selective pressure. Beetles DID lose the arms race for selection based on size, and so the ones that exist today fill niches where they compete on something other than size. Fossil evidence for that is going to be hard to find, as has been discussed. ---
**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:** [September 4, 2014, 7:15pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/29 "2014-09-04T19:15:43Z")
> [@Ornery\_Bob](#): > > _Suppose one species had genes which adapted faster, for whatever reason, then the other would slowly fall further and further behind over time._ > > Genes don’t adapt; they mutate randomly. Its the environment and ecology that determine if that mutation is an adaptation. The mutations keep on coming, regardless if they end up being adaptations. All other things being equal, one expects organisms with a higher mutation rate to evolve faster (because there is more raw material to work with), and those with a shorter generation time to evolve faster as well (because there is more opportunity for selection to work). This said, trees are somehow able to keep pace evolutionarily with insects that eat them, even though the insects have a much shorter generation time. ---
**Author:** ![Fotheringay-Phipps](https://avatars.discourse-cdn.com/v4/letter/f/d9b06d/32.png) [@Fotheringay-Phipps](https://boards.straightdope.com/u/Fotheringay-Phipps)\ **Post date:** [September 4, 2014, 8:17pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/30 "2014-09-04T20:17:15Z")
> [@Colibri](#): > > All other things being equal, one expects organisms with a higher mutation rate to evolve faster (because there is more raw material to work with), and those with a shorter generation time to evolve faster as well (because there is more opportunity for selection to work). It was my understanding that some creatures just tend to be more “flexible” in terms of genetic changes. A specific example I’ve always heard is dogs being more “plastic” as compared to cats; this being given as the reason there is more variation among types of dogs than among types of cats. > [@](#): > > This said, trees are somehow able to keep pace evolutionarily with insects that eat them, even though the insects have a much shorter generation time. But are the trees keeping pace evolutionarily? I am aware that trees have defenses against insects, but what I’m wondering is if the primary factor that keeps tree species alive on an ongoing basis is these defenses, or the fact that so many predators prey on insects that their populations are kept in check, which gives the trees “breathing room” so to speak. ---
**Author:** ![Shodan](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@Shodan](https://boards.straightdope.com/u/Shodan)\ **Post date:** [September 4, 2014, 8:18pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/31 "2014-09-04T20:18:11Z")
> [@Fotheringay-Phipps](#): > > Generally when you hear about species going extinct you hear about changes in environment, or new species being introduced etc. > > Question I have is if it’s possible for incremental changes in the predator or prey species to render the other obsolete, and unable to cope with predators or catch prey, as the case may be. > > Meaning suppose for example the predator or prey increases its speed or strength or the like and the corresponding prey or predator is not quick enough in adapting itself. > > This seems theoretically possible. Are there any instances where an extinction is attributed to this? Smallpox? Humans were the “prey” species, the smallpox virus was the “predator”, and humans used technology, which is the characteristically human method of adaptation/evolution and wiped out the prey species. Regards, Shodan ---
**Author:** ![Fotheringay-Phipps](https://avatars.discourse-cdn.com/v4/letter/f/d9b06d/32.png) [@Fotheringay-Phipps](https://boards.straightdope.com/u/Fotheringay-Phipps)\ **Post date:** [September 4, 2014, 8:44pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/32 "2014-09-04T20:44:44Z")
> [@Shodan](#): > > Smallpox? Humans were the “prey” species, the smallpox virus was the “predator”, and humans used technology, which is the characteristically human method of adaptation/evolution and wiped out the prey species. > > Regards, > Shodan Several people have suggested human examples. But I don’t know if these qualify. Humans have wiped out various species, but it’s not because humans have evolved faster than those species. Humans are not fundamentally different than they were a couple of thousand years ago when those species flourished. It’s the cumulative nature of human learning rather than adaptive genetic change that is the factor here. ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [September 4, 2014, 9:38pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/33 "2014-09-04T21:38:39Z")
> [@Colibri](#): > > It might also be mentioned that fossil faunas almost always include several predator species and several prey species. In modern faunas, for example, lions prey on zebras, wildebeest, and many other species, while zebras are preyed on not only by lions but by hyenas and wild dogs. Linking an extinction to a change in a single other species is going to be difficult unless it is an extremely specialized relationship. If they’re linked enough that the over-success of one could clearly be seen to be the cause of the extinction of the other, and it was the preditor species that over-succeeded, wouldn’t that send the predator species extinct as well? And even if Floobers only ever eat Flopsies and Flopsies are never eaten by anything other than Floobers, and one or the other go extinct; could we be sure that there wasn’t a disease or a parasite or a poisonous plant that either contributed or was the actual cause? ---
**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:** [September 4, 2014, 10:01pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/34 "2014-09-04T22:01:35Z")
> [@Yllaria](#): > > If they’re linked enough that the over-success of one could clearly be seen to be the cause of the extinction of the other, and it was the preditor species that over-succeeded, wouldn’t that send the predator species extinct as well? And even if Floobers only ever eat Flopsies and Flopsies are never eaten by anything other than Floobers, and one or the other go extinct; could we be sure that there wasn’t a disease or a parasite or a poisonous plant that either contributed or was the actual cause? Given that we generally have little detailed information about species known only from fossils, the answer is we can’t really tell. ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [September 5, 2014, 12:03am UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/35 "2014-09-05T00:03:40Z")
What about the smallpox variants that evolved to infect humans? I know humans are a bad example for almost every natural law, but if you think of virus as predator, and humans as the “prey”. The interaction provides a great example that’s accurately recorded. Predator is initially dominant, and ravages prey population. Prey responds by “evolving” a treatment that protects an individual from the virus’ predation, and a system to spread that treatment throughout the entire species population. Predator dies out from lack of vulnerable prey until the only remaining survivors are samples stored by the prey. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [September 5, 2014, 12:07am UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/36 "2014-09-05T00:07:19Z")
See posts 31 and 32, dstarfire. ---
**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:** [September 5, 2014, 4:14am UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/37 "2014-09-05T04:14:51Z")
> [@Fotheringay-Phipps](#): > > Generally when you hear about species going extinct you hear about changes in environment, or new species being introduced etc. > > Question I have is if it’s possible for incremental changes in the predator or prey species to render the other obsolete, and unable to cope with predators or catch prey, as the case may be. > > Meaning suppose for example the predator or prey increases its speed or strength or the like and the corresponding prey or predator is not quick enough in adapting itself. > > This seems theoretically possible. Are there any instances where an extinction is attributed to this? This sounds like the [Red Queen hypothesis](http://evolution.about.com/od/Terms-O-Z/a/What-Is-The-Red-Queen-Hypothesis.htm). And it has, indeed, been [implicated](http://www.sciencemag.org/content/341/6143/290.abstract) in the extinction of some mammals, at least. ---
**Author:** ![Shodan](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@Shodan](https://boards.straightdope.com/u/Shodan)\ **Post date:** [September 5, 2014, 12:52pm UTC](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270/38 "2014-09-05T12:52:12Z")
> [@Fotheringay-Phipps](#): > > Several people have suggested human examples. But I don’t know if these qualify. Humans have wiped out various species, but it’s not because humans have evolved faster than those species. > > Humans are not fundamentally different than they were a couple of thousand years ago when those species flourished. It’s the cumulative nature of human learning rather than adaptive genetic change that is the factor here. If you are limiting it only to genetic evolution, so be it. The secret to the success of the human species is that we evolve culturally instead of only genetically. This is not only far faster, but more flexible. In that sense, humans have “won” the evolutionary arms race, because we have hit on a way to develop new “armaments” over a few hundred years instead of a few hundred generations. Regards, Shodan [Previous page](https://boards.straightdope.com/t/can-a-species-win-lose-the-evolutionary-arms-race/697270.md?page=1)