{
  "export": {
    "source": "https://urth.darkrealm.vip/thread/urth/808",
    "note": "Exported from an unofficial mirror of a public mailing list. Copyright in each message remains with the person who wrote it.  Email addresses are obscured as `user at host`, the form the original archive published. This file was rebuilt from parsed fields rather than retained headers, so it is faithful in content but not byte-exact.",
    "addresses": "obscured as 'user at host'"
  },
  "archive": "urth",
  "thread": {
    "id": 808,
    "subject": "Digest urth.v013.n010",
    "messages": 1,
    "voices": 1,
    "first": "1998-06-16T07:30:01+00:00",
    "last": "1998-06-16T07:30:01+00:00"
  },
  "messages": [
    {
      "message_id": "<urth-v0014-0015@digest.urth.net>",
      "from": {
        "name": "Dan Parmenter",
        "address": "dan at lec.com"
      },
      "date": "1998-06-16T07:30:01+00:00",
      "subject": "(urth) Re: Digest urth.v013.n010",
      "in_reply_to": null,
      "reply_link": null,
      "blocks": [
        {
          "kind": "quote",
          "depth": 1,
          "text": "From: David_Lebling at avid.com\nI think the general explanation that is given in genetics textbooks is\nnot that the moths \"evolved\" a black color and then a white color.\nRather, there was (and is) a certain amount of genetic variation in the\nmoth population.  When pollution made the trees dark, there was\nselective pressure that favored darker colored moths (i.e., birds found\nand ate the light-colored ones).  So, after a while, the population was\nmostly dark-colored, but this didn't mean that the gene for\nlight-colored-ness disappeared: it just got less prevalent.  Eventually,\nthe pollution was cleaned up and the selective pressure went the other\nway, as the dark moths became more noticeable, so the occasional light\ncolored moth was able to reproduce, leaving more light colored moths,\nand so on."
        },
        {
          "kind": "text",
          "depth": 0,
          "text": "Yes, but as Mantis pointed out, it's often used as a \"textbook case\"\nof evolution.  I remember very well receiving just that explanation in\nmy eighth grade science class and I was being deliberately provocative\nin my post about it by taking the extreme position implied by Mantis'\npost."
        },
        {
          "kind": "quote",
          "depth": 1,
          "text": "If there is some representation of cayenne pepper genes in the moth\npopulation, then eventually dyeing the trees red will create selective\npressure favoring red moths.  Otherwise, you're in the position of\nwaiting for the moths to mutate at random into red.  This is roughly as\nlikely as turning a mouse's tail into a hand by slapping it against a\ntree."
        },
        {
          "kind": "text",
          "depth": 0,
          "text": "Yes, of course.  Mostly I just wanted to make that stupid pun;\nhowever, such an absurd statement could conceivably follow from an\nexplanation of evolution given in terms of Peppered Moths, which as\nyou've pointed out is something of a misconception, though it seems\nthat the same mechanisms are at work.  \n\nActually, we didn't get the part about the moths becoming white\nagain.  I heard about that later, in the context of a later discussion\nthat touched on the fact that the factories weren't putting out so\nmuch soot any more.  So perhaps my eighth grade teacher wasn't so\noff.\n\nDan"
        }
      ]
    }
  ]
}