{
  "schema": "evo-edu.notebook.reasoning_scaffold.v1",
  "id": "notebook.concepts.genetic-drift",
  "title": "Genetic Drift",
  "created": "2026-05-14",
  "updated": "2026-05-14",
  "status": "pilot-reviewed-scaffold",
  "concept_targets": [
    "genetic drift",
    "allele frequency",
    "population size",
    "fixation",
    "loss",
    "sampling error",
    "neutral change",
    "selection contrast"
  ],
  "site_links": [
    {
      "kind": "concept",
      "title": "Allele Frequency Change",
      "url": "/notebook/concepts/allele-frequency-change.html"
    },
    {
      "kind": "pack",
      "title": "Population Change",
      "url": "/evo/packs/population-change/"
    },
    {
      "kind": "app",
      "title": "Allele Tracker",
      "url": "/apps/allele-tracker/"
    },
    {
      "kind": "research_tool",
      "title": "Literature Explorer",
      "url": "/apps/literature-explorer/"
    }
  ],
  "records": [
    {
      "id": "gd-001",
      "type": "mechanism-contrast",
      "question": "What makes drift different from selection?",
      "answer_summary": "Drift changes allele frequencies by random sampling. Selection changes frequencies because heritable variants differ in survival or reproduction.",
      "verification_prompt": "Ask whether the evidence shows consistent directional advantage or strong variation among repeated runs.",
      "misconception_guard": "Do not treat any increase in frequency as proof of selective advantage.",
      "didactopus_prompt_seed": "State one observation that fits drift and one that would make selection more plausible."
    },
    {
      "id": "gd-002",
      "type": "scale-check",
      "question": "Why is drift easier to see in small populations?",
      "answer_summary": "Sampling error has a larger effect when fewer individuals contribute to the next generation, so allele frequencies can swing more sharply.",
      "verification_prompt": "Compare repeated small-population and large-population runs from the same starting frequency.",
      "misconception_guard": "Do not describe drift as weak selection; chance sampling is a different mechanism.",
      "didactopus_prompt_seed": "Explain why two small-population runs with the same starting settings can end differently."
    },
    {
      "id": "gd-003",
      "type": "definition-check",
      "question": "What does fixation mean?",
      "answer_summary": "Fixation means one allele reaches frequency 1.0 in the population, while alternatives are lost.",
      "verification_prompt": "Identify the final population frequency and whether competing alleles remain.",
      "misconception_guard": "Do not assume fixation proves the fixed allele was better adapted.",
      "didactopus_prompt_seed": "Describe a drift-only path to fixation without using the language of benefit or design."
    },
    {
      "id": "gd-004",
      "type": "evidence-check",
      "question": "Why compare repeated runs?",
      "answer_summary": "Repeated runs show whether a result is consistently directional or varies strongly, which helps distinguish more stable selective pressure from drift-dominated change.",
      "verification_prompt": "Compare multiple runs under the same settings before naming the mechanism.",
      "misconception_guard": "A single dramatic run is not enough to settle the mechanism.",
      "didactopus_prompt_seed": "Rewrite the first explanation after seeing four more runs under the same conditions."
    },
    {
      "id": "gd-005",
      "type": "mixed-mechanism",
      "question": "Can drift and selection both matter?",
      "answer_summary": "Yes. Small populations can show noisy outcomes even when selection is present, and weak selection can be hard to distinguish from drift without more evidence.",
      "verification_prompt": "Ask whether the pattern remains after repeated runs or stronger evidence of fitness differences is added.",
      "misconception_guard": "Do not force every case into a drift-only or selection-only explanation when mixed mechanisms are plausible.",
      "didactopus_prompt_seed": "Name what extra evidence would help sort out a mixed drift-selection explanation."
    }
  ],
  "citegeist_source_slots": [
    {
      "slot": "drift-foundations",
      "needed_for": "Foundational treatments of drift, sampling, and population size",
      "candidate_queries": [
        "Wright 1931 evolution in Mendelian populations genetic drift",
        "Sewall Wright genetic drift population size fixation"
      ],
      "review_status": "pending"
    },
    {
      "slot": "neutral-theory-context",
      "needed_for": "Neutral or near-neutral explanations relevant to drift interpretation",
      "candidate_queries": [
        "Kimura 1968 evolutionary rate at molecular level neutral mutation",
        "neutral theory drift fixation molecular evolution"
      ],
      "review_status": "pending"
    }
  ],
  "doclift_use": "Use this JSON as a fixture for extracting or validating scaffold-backed concept pages about population-genetic mechanisms.",
  "groundrecall_use": "Store rationale, pending source-slot work, and later revisions as durable notes so related Notebook concepts can reuse the distinction between drift and selection.",
  "next_review_steps": [
    "Backfill reviewed sources for Wright and later drift or neutral-theory explanations.",
    "Add one paired small-population versus large-population worked run with fixed parameter values.",
    "Link this page into later Notebook pages on adaptation and population genetics."
  ]
}