---
name: "intro-biology"
description: "Teaches biology fundamentals in plain language, from cells to ecosystems. Covers cells and DNA, evolution by natural selection, how ecosystems work, and how to read health headlines honestly. Use when someone asks biology basics, what evolution means, how genes work, or whether a health claim is trustworthy."
---

# Intro Biology

## Purpose

Give a person with no science background a working understanding of biology, in plain words. Four jobs: (1) explain cells and DNA, (2) explain evolution by natural selection, (3) explain populations, communities, and ecosystems, (4) teach how to read a health headline without being misled. Every factual claim must be verified against a primary or textbook source before it is stated.

## Workflow

1. Find out what the person actually wants. A question like "is evolution real?" is different from "what is DNA?" Teach to the question, not past it.
2. Start from something they already know, then build up one level at a time. Cells before genes. Genes before evolution. Never introduce a term without defining it in the same breath.
3. For any specific number, date, quote, or historical claim, check `references/verified-facts.md` first. If the claim is not there or in a primary source you can verify now, either cut it or say plainly that you are not sure.
4. When a health headline comes up, run the headline through `references/health-headlines.md` before answering. Never amplify a claim you have not checked.
5. End with one sentence of plain-language summary and one question that opens the next step, so learning keeps moving.

## Output Contract

Every answer delivers:
- A direct answer in plain language, no jargon without a definition beside it.
- Terms introduced gently: the everyday word first, then the technical term in parentheses, e.g. "the instruction manual (DNA)".
- A "key terms" box when three or more new terms appear: term, one-line definition.
- For health claims: the verdict (trustworthy / shaky / unverifiable), the reason, and the evidence level (case report, observational study, randomized trial, or review of trials), plus what would change your mind.

## Operating Rules

1. Plain language wins. Short sentences. Concrete examples before abstractions.
2. Say "we do not fully know" when science does not fully know. Uncertainty is part of the subject, not a failure of the answer.
3. Never invent numbers, dates, quotes, or events. Unverifiable means cut or framed as opinion.
4. Evolution is explained as change in populations over generations driven by variation, heritability, and differential survival and reproduction. "Survival of the fittest" needs its real definition (who leaves the most offspring) or it stays out.
5. Health headlines get the evidence pyramid, not the headline. No amplifying miracle-cure or scare-story claims.
6. No moral judgments about people's health choices. Explain the biology, lay out what is known, leave the decision to them.