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How does this affect the theory of evolution? In the 90s in high school, we were taught that random mutations create diversity among a species and then natural

• delinka 8y ago
  "The random thing" is indeed efficient. That's why it takes millions of years to evolve from single-celled organism to what you see on the planet today.
  • annamargot 8y ago
    Yeah, that’s what my teachers said too. “Millions of years. End of conversation. Put your hand down, son.” It always seemed a little dismissive of the potential of our now very complex organisms to use feedback if only purely random mutations were at play. Instead of random mutations full stop, how about informed best guess mutations targeted at potentially stressed areas of the body.
    • delinka 8y ago
      While I suppose "informed best guess" might be possible, I don't see how this 'intelligence' makes it into the process. Liver more stressed in this particular organism? Tweak the DNA in the reproductive organs. I don't think we even have a theory that could explain how that should work. Maybe we'll get there one day. But I suspect, as has been demonstrated in labs with bacteria, that it really is random. When their environment begins to show signs of contamination, the bacteria's inner workings don't use an "informed best guess" when mutating for reproduction - the random changes result in bacteria suited for death with exposure to the contamination, and bacteria that are more resistant to the contamination. Guess which ones survive to pass on the trait.
    • dahlueblojen 8y ago
      To be fair most grade school teachers just have a bachelor's in their subject (if you're lucky) (also don't include masters of education, that's about teaching, not the subject matter being taught) that they aquired a decade or so ago. It's not surprising if what they know is well what they were taught and not what is most current.
      • jedberg 8y ago
        That's very dismissive of teachers. Yes it's true, some teachers are lazy like this. But you got a few things wrong. First off, if you teach at the middle or high school level, you have to have a masters in the subject you teach. It's called a single subject credential. Secondly, just like college professors, who continue to learn about new developments in their field, a lot of K-12 teachers, and especially 7-12 teachers, do that too. They also read papers and also attend conferences to learn the latest developments in their field.
        • dahlueblojen 8y ago
          I'm highly suspicious that your first claim is not true for all U.S. pubic schools (or even a sufficiently significant portion). I'm sure it's the case in some States. 2nd case is probably fair, though I think a lot of people, myself included, have has experiences with teachers that definitely didn't pay attention in those seminars if they attended. (And in my case that's just with 1.5 years of middle school)
        • extra88 8y ago
          > if you teach at the middle or high school level, you have to have a masters in the subject you teach. That’s not true, some states don’t require a Masters in any subject, let alone in one relevant to what they’re teaching. https://study.com/articles/High_School_Teacher_Requirements_and_Career_Information_for_Those_Interested_in_Teaching_High_School.html https://study.com/articles/High_School_Teacher_Requirements_... https://teach.com/become/teaching-credential/state-requirements/ https://teach.com/become/teaching-credential/state-requireme...
    • extra88 8y ago
      That would require an intelligence to be informed and to make a guess. There is none.
      • CuriouslyC 8y ago
        Would you consider yourself an informed intelligence making guesses? What makes you different from the rest of the universe? Do you think the scale at which we exist is somehow special?
        • extra88 8y ago
          Yes. Lots of things; I’m warmer, I contain more matter by volume than average, and I emit information in response to queries, even stupid ones. Yes.
          • ratacat 8y ago
            Is it possible that the information emitted by the universe to queries simply escapes you.
    • aperiodic 8y ago
      Somewhat related, Leslie Valiant believes that if evolution performs a random search in genome space, it is computationally impossible for it to have led to the complexity that it's produced in only a few billion years. He's written a fascinating paper exploring what other algorithms besides random search could perform the computational task required and are also biologically plausible: https://dash.harvard.edu/bitstream/handle/1/2643031/valiant_evolvability.pdf?sequence=4 https://dash.harvard.edu/bitstream/handle/1/2643031/valiant_...
      • deleted 8y ago
        [deleted]
      • annamargot 8y ago
        Very cool. Thank you
• ganeshkrishnan 8y ago
  We have much more information than the 90's school which in turn had information few decades outdated. Some new stuff include: epigenetics, the role of 'junk dna', small RNA etc. Overall I am very enthusiastic about epigenetics
  • zawerf 8y ago
    I wonder where you can find erratas based on the edition of education you got. (e.g., if you grew up in the 90s you should know pluto is no longer a planet) Mostly interested in basic scientific knowledge (say high school level) that has been updated.
    • Mirioron 8y ago
      That would be a great project.
      • ccozan 8y ago
        Great for people who might wake up from a coma. Or frozen.
        • mrexroad 8y ago
          ... as well as those who return to a subject decades after formal education. ... or those trying to have an meaningful conversation with someone from another generation. I honestly have no idea what my parents were taught in school. I’ve often wonder how much of this plays into the narratives that get exploited in politics.
    • derefr 8y ago
      You might be able to do something automatic using Wikipedia article version history for articles that have been “complete” for s long time. Diff them over long time-scales, generate “release notes”, summarize.
    • abathur 8y ago
      Good point. A thoughtful, digestible source of such updates might even help undercut one source of inter-generational alienation.
• extra88 8y ago
  Behavior and environment are largely how natural selection operates, it has never been thought otherwise. More colorful bird is selected as a mate, thicker fur survives the winter, etc.
  • annamargot 8y ago
    I should have specified. I meant with regard to the mutations specifically.
    • chiefalchemist 8y ago
      New mutations create new possibilities. What the article seems to say is, there's quite a bit of info embeded in genes, but there are additional factors that twigger which traits are called into play. It's a very sophisticated system.
• zzbzq 8y ago
  It's actually complicated. In the 19th and 20th century, scientists debated how evolution and speciation could take place. The Darwinian side said it was purely chance-based mutations combined against selective pressures--natural selection. The Lamarckist school suspected this was statistically unlikely and posited that organisms had the ability to pass down acquired traits. They debated fiercely, and the Darwinists declared victory based on Occam's razor because no mechanism was ever discovered whereby acquired traits could be transmitted. In the 2000s, the U.S. saw some political controversies in which creationists tried to have their anti-evolutionary religious views included in classroom science. The debates around that issue helped solidify a new dichotomy of science vs. religion when it came to the discussion of evolution. During the same era, the study of epigenetics was becoming popular. Owing perhaps due to the aforementioned political discourse of the era, the public at large has allowed epigenetics to be subsumed into the existing theory of evolution as if it is no change at all. From a different perspective (a la the Lamarckists of centuries past,) it represents the possibility of a diametrically opposed paradigm shift. In these comments there are already comments dismissing epigenetics matter-of-factly as just a part of natural selection. In the purview of scientific history, it's the opposite of natural selection. To answer your question, the reality is this is very different than what you were taught in the 90s, except that we've rewritten history for science to save face and pretend we knew this all along, and to forget that this sort of thing was explicitly rejected by the Darwinian victors 100 years ago.
  • opportune 8y ago
    Epigenetics and Lamarckian evolution are not mutually exclusive with natural selection, even historically. Lamarckian evolution is natural selection, simply through a non-genotypic mechanism, which epigenetics could be a part of. Also, the heritability and stickiness of epigenetics is still not well known. It cannot be the main driver of evolution over long intervals (i.e. hundreds of thousands of years) because it is limited in the changes it can make: methylation, for example, can only affect the expression of genes, but it cannot alter them, nor can it introduce new genes.
    • xyhopguy 8y ago
• tasty_freeze 8y ago
  That is the cartoon version. The raw stuff of evolution is variation and selection pressure. Mutations are an important long-term contributor to variation, but most variation isn't due to mutation. Eg, my two parents had five sons, and while there are some similarities, there are a lot of differences too. None of the variation was because of mutations.
  • 13of40 8y ago
    Sorry for the ELI5, but if the differences aren't due to [genetic] mutation, how do they get passed on to future generations?
    • Bromskloss 8y ago
      I think the point is that variation is created by taking some material from the mother, and some from the father. A _mutation_ also creates variation, but refer to things like replications errors and "bit flips" due to, say, radiation.
      • 13of40 8y ago
        But those aren't differences in the same way that mutations are. The chromosomes passed on by the grandmother are identical to those received by the granddaughter, unless you're talking about spilicing genes between chromosomes. The morphological differences in the daughter are from the genes being expressed differently in the context of her body and the father's DNA. (Or so 90's science class would have me believe.)
        • gonvaled 8y ago
          The daughter has some genes from the mother, and some from the father. Which genes are selected from which progenitor is random. To have a big pool for recombinations, inbreeding is to be avoided and populations must be big enough.
          • 8y ago
• TangoTrotFox 8y ago
  I think there's a related issue here that's always kind of nagged at me. We have evolved many characteristics which are handy, but which seem unlikely to have had enough of an impact on survival to have become so ubiquitously propagated by natural selection alone. For instance the ability to digest milk as well as white skin are both relatively new adaptations. But the advantages they offer, for the locations where they evolved, are pretty mild. Fair skin could have had sexual selection factors in play helping its spread, but being able to digest the milk of lactating animals? It just doesn't seem like a mutation that would provide enough benefit to become ubiquitous through the mechanisms of natural selection alone, yet it did. And both of the above evolutions are relatively recent, making it all the more difficult to reconcile things through random mutations filtered by natural/sexual selection alone.
  • torstenvl 8y ago
    I'm confused by your viewpoint. How is a fuller ability to extract nutritionally-complete food from your environment in winter not an advantage you'd expect to be selected-for? People who are malnourished produce poorer sperm. People who are malnourished are not looked on as good mates who can bear children or provide food for the family. People who are malnourished die earlier, perhaps starving to death before reproducing (or reproducing as much).
    • TangoTrotFox 8y ago
      Think about your usage of the word word people - as opposed to the singular. In a purely random natural selection driven system, propagation relies on the success of a single mutated individual until we get to very large populations where randomness could more regularly yield similar mutations among different people. Because of this, in the purely random natural selection system the magnitude of an effect is extremely important. Let's imagine we can somehow quantify exactly how likely a specimen is to survive in a certain area per year, we'll call that value x. Imagine x is some percent per year. How much would a random specimen suddenly developing lactose tolerance increase that percent? In the case of something like Darwin's birds, the percent improvement from beak changes would be very substantial. That mutation would open up entirely new, and vast, resources of food available at all times and completely independent of everything else. In the case of milk, you need a lactating animal to start with. That already implies you have multiple sources of food in extremely healthy shape. That little catch there already ensures that this mutation would not provide a substantial benefit in a one-off scenario. By contrast, imagine our mutations are not entirely random. And that our bodies, somehow, trend towards more desirable mutations over time -- meaning we don't see just a one-off instance of favorable mutations but them tending to occur over and over again. In this case your language of "people" would be entirely appropriate. Over time, even a small survival edge means a lot and, given enough samples, we'd certainly expect this trait (and any trait for that matter) to start to 'stick' in any area where its net effect on survival was basically anything above 0.
• acqq 8y ago
  You are on Hacker News, have you never tried some genetic algorithms? Then try to calculate how many parallel “computers” are available on Earth, and how often, and for how long. It all fits.
• zaarn 8y ago
  While it's a very simplified version, basically yeah. Nature doesn't really care about efficient, if you want proof of that just look into various places in our body. All over the place you seem completely idiotic design that is merely a result of nature just choosing the lazy, quick and dirty route over the efficient one.
  • annamargot 8y ago
    That’s interesting. Could you name a few examples?
    • zaarn 8y ago
      IIRC from my biology book, the nerve for controlling the voice box goes from the brain, down to the heart, loops through the aortic arch over the heart and then goes back up to the voice box. In giraffes this nerve can be 4 meters long. The likely reason for this layout is that the nerve originally routed to the gills, which were on the height of the heart until the neck extended and the heart moved lower in the body.