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In case anyone is wondering about the size of the effect, https://www.nationalgeographic.com/animals/article/wildlife-watch-news-tuskless-elephants-behavior-cha

• csours 5y ago
  Evolution is an umbrella term, but in the most general form, evolution means a change in genetics in a population over time. So yes, the genetic 'option' was there before, but it is advantageous now.
  • VeninVidiaVicii 5y ago
    And this is why genetic diversity is a good thing.
    • rustyminnow 5y ago
      Hmm in the context of the article, I'm not so sure it's a good thing. Later on they mention that if this genetic trait gets passed on to males, they die. So along with hunting, males are doubly at risk. It may be advantageous for the survival of an individual to be born without tusks, but it doesn't sound too good for the survival of the species.
      • netcan 5y ago
        The trait may or may not be advantageous. Diversity is. In this case the selective pressure is poaching, but selective pressures are constant. Diversity is a bank of genetics that the population can draw from to adapt and survive. Traits that are rare, are often rare because of shortcomings. But if environmental changes make that tradeoff worthwhile, it can be made. Meanwhile, evolution doesn't stop. Once the trait/gene is common there is positive selective pressure on complementary genes. Over time, these may mitigate or compensate for the negative traits that have acquired. Of course, on the timescales that humans tend to selectively pressure species, there isn't time for all this elegance to emerge, usually.
        • rustyminnow 5y ago
          This is all true. You make very good points. My parent said: > And this is why genetic diversity is a good thing. I guess what I meant was: genetic diversity is a good thing. But this particular case is not a great example for illustrating why.
      • hanniabu 5y ago
        Why do they die? Because they can't protect themselves? Or does the trait come with other less desirable side effects for males?
        • jbay808 5y ago
          The trait appears to be lethal to males and they do not make it to birth. It may be the case that at least one typical X chromosome is necessary for survival, and males only get one X chromosome.
    • micromacrofoot 5y ago
      Yes, but in the long run isn't this breeding out this specific diversity? I recall reading that genetic diversity becoming limited in endangered species makes them much more susceptible to being wiped out by disease.
  • gowld 5y ago
    Evolution has two main components. The random variation was already there. The natural selection is doing its part now.
    • deleted 5y ago
      [deleted]
    • Hamuko 5y ago
      A man with a gun doesn't sound like "natural selection".
      • Spivak 5y ago
        Humans are animals and predators like any other in this situation.
        • ricktdotorg 5y ago
          Why downvote parent? A human is a "natural" predator just with different methods of attack/more intelligence than "animals". Why is a human predator (an "apex predator" if you will) any less "natural" than a T-Rex? Or any other animal that forced evolutionary change?
          • jwhitlark 5y ago
            Because of civilization. While the word "artificial" is certainly overloaded, this is basically what we've designated the word to mean. That's not to say a human couldn't be a "natural" predator, if you assumed an isolated tribe, but that's certainly not what's happening here. If we call this natural, there is no longer any meaning you can ascribe to artificial.
      • rsj_hn 5y ago
        Why not? I often see people draw this distinction between humanity and nature, as if we weren't part of nature, and there is something deeply misanthropic about it. Of course we are part of nature. We may be screwing over the habitat of other animals -- like rabbits in Australia or pythons in the everglades -- but we are certainly part of nature and this is a textbook case of natural selection at work.
  • ehsankia 5y ago
    Not only is it more advantageous, it actually was force selected for (IIRC, poached elephants are often left for dead). So this is closer to selective breeding/artificial selection more so than natural selection.
    • cromka 5y ago
      That's precisely what the article linked points out.
    • jbattle 5y ago
      What's the difference in this case? Doesn't seem too different from how camouflaged eggs would have developed (maybe just faster because the selection mechanism is so strong). When I think of selective breeding I think of humans picking out which animals (cows/dogs/wheat/etc) get to reproduce.
      • IggleSniggle 5y ago
        Right, selective breeding is just a subset of natural selection. Not sure why folks seem to want to exclude humans from nature, like we’re not part of the exact same system.
        • sellyme 5y ago
          > Not sure why folks seem to want to exclude humans from nature Probably because the concept of "nature" no longer serves any purpose if you don't, as it doesn't exclude anything. It's often a pointless distinction to make (see also: anything that labels itself as "organic"), but it's a convenient shorthand to describe a category of interactions that people often want to talk about.
          • IggleSniggle 5y ago
            Perhaps, then, "nature" is a somewhat dated concept that is no longer especially useful to have in such broad circulation, given that it encourages folks to exclude humanity from analysis and understanding of the "natural" system?
  • bialpio 5y ago
    Except it's only advantageous to female elephants, according to the article: "They identified two likely genes AMELX and MEP1a, which are passed from mothers to the offspring on the X chromosome. But if a disrupted gene is passed in a male elephant, the elephant dies; the female elephant would instead evolve to be born without tusks. " What would be the effect of this on male elephant population when taken to the limit (i.e. 100% of females are tuskless)? Seems to me that it'd skew the proportion of births towards 2:1 (assuming it's now at 1:1)? How significant impact would that have to the species as a whole?
    • esturk 5y ago
      Maybe not as much as you would think. Naturally, not all males mate and the mating ratio is not always 1:1. Take humans for example, it's been shown our ancestors comprise mostly of females in a ratio roughly 3:2 to males. That is, some male ancestor probably mated with more than one female ancestor somewhere.
      • thaumasiotes 5y ago
        > it's been shown our ancestors comprise mostly of females in a ratio roughly 3:2 to males. I thought it was 2:1.
      • caymanjim 5y ago
        I don't know what the numbers are like for elephants, but in many species, most males don't get to mate at all, and a handful of dominant males mate prodigiously. Even if tuskless males were viable, they'd fail miserably at mating if there were tusked males around, because they'd get their asses kicked.
      • AussieWog93 5y ago
        >our ancestors comprise mostly of females in a ratio roughly 3:2 to males. For anyone else wondering how this is possible on an individual level, apparently a lot of people used to reproduce with their first and second cousins.
        • 5y ago
  • mfer 5y ago
    Is this actually evolution? I ask because it’s not a change in the genetic structure of elephants. It’s an existing trait becoming more wide spread.
    • jawarner 5y ago
      Yes, this is evolution, and that's generally how evolution works. There is some diversity in a population, and natural selection promotes some traits over others.
      • mfer 5y ago
        Looking at definitions in dictionaries I don’t see this. What am I missing? Honest question. There are no new species and there is no change to genetic code
        • MAGZine 5y ago
          genetics is random. Each new generation combines genetic material from their ancestors, plus some new random mutations. natural selection, i.e. the environment they're born in, is what picks winners and losers among those inherited characteristics and mutations. Almost all individual mutations on a genetic level are benign. It's the combination of (selection of specific trait + compounding change) that is what we know as evolution. In this case, the "change to the genetic code" produces elephants without tusks. That happened by change. But now, the elephants without tusks are the ones who get to live, because they're not poached. That specific mutation allows them to live/thrive. In the same way better hearing might allow a bird to evade its predators. "no change to genetic code" ignores the fact that there are elephants wandering around who don't have (and will never have) tusks. (also: evolution is quite slow. this by any right is a huge, "forced" evolution. not in that we forced a change in the genetic code through editing it, but we are changing the course of genetics in a species through our collective behaviour).
        • meej 5y ago
          Evolution doesn't necessarily imply "new species" (species is actually a pretty vague term) and dictionary definitions are limited. Try this resource instead: https://evolution.berkeley.edu/evolibrary/article/evo_01 https://evolution.berkeley.edu/evolibrary/article/evo_01
  • ssener2001 5y ago
    How can evolution know it has advantage. Do you see Human beings's actions or predicts? And how can evolution know how it will change genetic code?
    • bagels 5y ago
      Evolution doesn't know anything. Tusked elephants are being killed, and the tuskless live on to breed.
  • achenatx 5y ago
    change in genetics is not really evolution, it is just mutations. Evolution is environmental selection of advantageous mutations.
• dheera 5y ago
  As sad as this is, how does this kind of evolution happen? I imagine the poaching process doesn't actually differentiate tusked and tuskless elephants, both types of elephants would fall into the trap and die? And then if it has tusks the poachers take them, if it doesn't have tusks the poachers just abandon the dead elephant? Or does their trap actually trap them by the tusk?
  • jsnell 5y ago
    They're hunted interactively by people with guns, not passively with traps.
    • cabalamat 5y ago
      Traps wouldn't work because the authorities would get to the elephant in a trap before the poacher returned, thus the poacher would lose their prey. The poacher could always hang around near the trap, but if you're doing that you might as well just shoot the elephant, not trap it.
  • varenc 5y ago
    Yea I assume poachers shoot elephants, not trap them. So they only want to shoot ones with visible tusks. Edit: I found an article[0] describing some poaching methods and apparently they do use traps! Including snares and a spiked board. But that it appears homemade shotguns and rifles are the most common method. [0] http://www.open-earth.org/document/natureR_main.php?natureId=283 http://www.open-earth.org/document/natureR_main.php?natureId...
• drtz 5y ago
  > It started off about as common as humans having green eyes. Elephant poaching has been around since long before the Mozambique civil war. The number of tuskless elephants may have been at 2-4% prior to the war, but that doesn't mean that lower levels of poaching didn't push it up to that level from some much lower naturally-occurring level. 2-4% seems like a _very high_ rate for a trait that could negatively impact a female's chance of survival AND kills 100% of her male offspring.
  • jbay808 5y ago
    Further to your point, I read elsewhere that the base rate in captivity is closer to 0.5%.
    • Stevvo 5y ago
      Human behavior probably has the opposite effect in captive elephants. If a captive elephant is born without tusks then the Mahout is going to kill it rather than invest in rearing an animal that has much reduced utility and will not yield healthy offspring.
      • unmole 5y ago
        Elephants are not really bread in captivity.
        • bruckie 5y ago
          While that's generally true, there are exceptions. Elephants at the Oregon Zoo have birthed more than two dozen babies over the past several decades. https://www.oregonzoo.org/node/1948/media https://www.oregonzoo.org/node/1948/media
        • tokai 5y ago
          They are bread in captivity. In Europe the breeding is organized by the European Endangered Species Programme. https://nhatrangbay.net.vnwww.eaza.net/assets/Uploads/EAZA-Documents-Other/EAZA-Position-Statement-on-the-Evolution-of-Elephant-Management-Systems-at-Member-Zoos-FINAL.pdf https://nhatrangbay.net.vnwww.eaza.net/assets/Uploads/EAZA-D... https://www.elephant.se/elephant_breeding_in_europe.php https://www.elephant.se/elephant_breeding_in_europe.php
• dan_mctree 5y ago
  Is anyone else surprised at how quick species can seem to evolve in these kinds of ways? Asian and African elephants are supposed to have separated millions of years ago, yet still strongly resemble one another. Yet in a few decades, something as fundamental as the presence of their tusks can shift dramatically. And that in a species with very long gaps between generations. It makes me suspect there's something else going on here that's not just good old natural selection. Have they done any tracking to confirm the tuskless elephants are actually being born to tuskless mothers? Or could it be that the parents are actually affecting the way their offspring are born in some lamarckian-esque sense? If there'd be some trick animals can pull to change their offspring in some ways, that ought to be highly effective for long term species survival and should thus be highly selected for.
  • formercoder 5y ago
    Seems like the relative death rates of tusked vs tuskless would matter. Remember the 32% is a percent potentially on a small number. Say to an extreme 99% of tusked elephants were killed, 99% of tuskless were unharmed. If tuskless is a genetic traight, it takes over very quickly even though total population size is smaller.
    • psyfi 5y ago
      Exactly that! I think it is ridiculous to think that more elephant are born without tusks as a kind of "random selection" or even adaption
  • imtringued 5y ago
    What do you mean by quick? Evolution is just random mutations. You're basically trying to diversify and spread risk. If there is huge selective pressure only a handful of genes will survive and when they reproduce they will be over represented compared to the previous generation.
  • burnished 5y ago
    Nah, looks like natural selection. The article mentions that "The phenomenon of elephants going tuskless is not new. Researchers found the number of tuskless female elephants in Mozambique increased by almost double over 30 years. This overlaps with a period of civil conflict, where armed forces slaughtered 90% of the elephant population to produce ivory.". That is a LOT of selection pressure. Also, the African Elephant Specialist Group (AfESG) [1] published a graph of elephant populations, the reduction in total numbers is pretty dramatic. You might liken this to the way that humans in small, isolated communities will also start to differentiate in a hurry (forex, that one blue family). [1] https://ourworldindata.org/grapher/african-elephants https://ourworldindata.org/grapher/african-elephants
• sriram_sun 5y ago
  I had a couple of questions: Are 100% of tusked females giving birth to 32% of the newborns without a tusk? What % of tuskless females give birth to tusked females?
• gwerbret 5y ago
  The first figure of the paper they reference [0] has the numbers for this study: -- 18.5% of females were tuskless before the war -- 50.9% of females were tuskless after the war -- 33% of females were tuskless in the first post-war generation Of the offspring: -- 8.7% of females born to two-tusked females were two-tusked -- 44.7% of females born to tuskless females were tuskless [0]: https://www.science.org/doi/10.1126/science.abe7389#F1 https://www.science.org/doi/10.1126/science.abe7389#F1
  • juki 5y ago
    > -- 8.7% of females born to two-tusked females were two-tusked ... were tuskless, you mean?
    • gwerbret 5y ago
      Yes, sorry!
• saghm 5y ago
  Now I'm worried that in a couple hundred years a third of humans will have green eyes because all the blue ones have been harvested by aliens.
• baby 5y ago
  Downvoted for weird statements about green eyes. If there is a back story include it in your comment.
  • tommit 5y ago
    What? They were just comparing the average rarity of the trait within a population. Literally googling "green eyes" would have given you the backstory: https://en.wikipedia.org/wiki/Eye_color#Green https://en.wikipedia.org/wiki/Eye_color#Green
• 8eye 5y ago
  wait what? i didn’t realize my green eyes were rare. interesting and also that’s a huge jump from 2-4%, honestly at least we don’t have to worry about them going extinct, but still sad