Biological Evidence
📋 What it is
Biological evidence like DNA can identify a person with extremely high certainty.
🗣️ Coach says
DNA is the ultimate identifier. Everyone’s DNA is unique (except identical twins), and it’s in almost every cell — a hair root, saliva, skin. A DNA match points to one person out of billions, which is why it’s so powerful.
🧠 Memory hook
DNA = a near-unique biological ID, found in almost every cell you leave behind.
😂 Giggle
Why was the handwriting sample nervous?
It knew it was about to be compared!
😲 Whoa!
DNA fingerprinting was invented in 1984 and freed its first WRONGLY-convicted person in 1989 — forensic DNA has both convicted the guilty and exonerated the innocent.
✅ Quick check: Why is a DNA match considered very strong evidence?
Say your answer out loud first — then reveal.
Because DNA is essentially unique to each person, so a match points to one individual out of billions.
Near-uniqueness makes DNA a powerful identifier.
🪄 Trick question: Can DNA evidence prove someone INNOCENT, not just guilty?
Careful — think it through, then reveal.
Yes — DNA that doesn’t match, or matches someone else, has freed many wrongly-convicted people.
Evidence cuts both ways: it can exonerate as well as implicate.
🧪 Try it! (2 minutes)
Every cell has DNA — gently rub the inside of your cheek; those cells all carry your unique code.