About this resource
In most elephant herds, only about 2–6 of every 100 females never grow tusks. In Mozambique’s Gorongosa National Park, more than half of the older females have no tusks. Why are so many Gorongosa elephants tuskless? Natural selection is a numbers game: helpful inherited traits become a bigger share of a population — and less helpful ones shrink — generation after generation. In this one-week, 5-level Natural Selection Math & Population Traits unit for middle school science (NGSS MS-LS4-6), students investigate a real mystery, then use their evidence to crack the case.
The Tuskless Mystery is part of Science Unlocked, a series of mystery-driven lesson sets. Every set opens with a real, surprising phenomenon, builds the science one level at a time, and ends with students solving the mystery in a claim-evidence-reasoning (CER) write-up.
Topics: natural selection, adaptations, claim evidence reasoning (CER), science phenomenon, review games.
What's included
- Teacher Deck (88 slides, PowerPoint). Answers are highlighted on the slides. Speaker notes tell you what to say and do, what to watch for, and how to support students or push GT students further. Prep slides and answer keys are hidden, so they skip during a slideshow.
- Interactive Student Deck (55 slides, PowerPoint + PDF). Students type in boxes, drag cards and check marks, and rate their confidence. Assign one copy per student in Google Classroom or your LMS.
- Google Slides versions of both decks. Click a button in the Google Slides Links PDF to make your own copy in Google Drive.
- Teacher Guide (22-page PDF). The standard, a week at a glance, a materials list, misconceptions to watch for, a run-of-show for every level, answer keys and sources.
- Student Printable (19-page PDF + a low-ink greyscale copy). The same tasks on paper in 12 pt type, for students without devices, sub days, or anyone who learns better with a pencil. Slide numbers match the Student Deck.
- Self-grading digital activity. SCORM 2004 and SCORM 1.2 packages for an LMS that accepts SCORM uploads, a web package, and a single HTML file that opens in any browser. Notes, sorts, matches, tables and multiple-choice items grade themselves, and students get a copy-and-paste backup of their work. A 2-page teacher quick start is included.
- Two whole-class review games that open in any browser: a Jeopardy-style game (6 categories, 30 clues) and Trashketball, where teams answer on whiteboards and then shoot for points.
- Kahoot! and Blooket import files. 48 review questions, one file per level plus an all-levels file, with a printable answer key.
- Start Here guide, HTML & SCORM how-to guide and Terms of Use, so you know which file to open first.
The 5 levels (about one 45–50 minute class each)
- Counting Tusks. Traits, variation, populations, inherited vs. acquired, percents. Key activities: Tuskless mystery, inherited/acquired sort, herd percent table.
- Survive and Pass It On. Natural selection, probability (more likely, not certain). Key activities: War clues, moth order, beetle survival math, fact/myth sort.
- Moth Hunt Lab. Simulation over 8 generations, % tables, line graph. Key activities: Moth Hunt (sooty bark leads to clean bark), graph, Lab Conclusion CER.
- Rise and Fall. Real data: peppered moths and Darwin’s finches — traits up AND down. Key activities: Moth story, real graph, finch math, more/less common sort, daughters clue.
- Crack the Case. Stretch HS-LS4-3: shifting distributions, the tusk case. Key activities: Distribution graph, Stretch CER, case-file graph, final CER.
Built for real classrooms
- Every level follows the same routine: "I can" targets with a confidence check, a warm-up, copy-it notes with a word bank, hands-on practice, a checkpoint students must pass to unlock the next step, and an exit ticket. A 10-item Mini Quiz wraps up the week.
- Level 1 opens with a Power-Up on the earlier-grade ideas this standard builds on (3-LS3-1, 3-LS4-2, 3-LS4-3).
- The last level includes a high school Stretch (HS-LS4-3) that every student tries and advanced students can take further.
- Hands-on lab (Moth Hunt: The Investigation). Student materials list: Black construction paper (sooty bark), a newspaper sheet (clean bark); 20 starting moths: 10 light (newspaper), 10 dark (black paper) dots; Supply cups of extra light and dark dots, an “eaten” cup; Data table (deck or paper). Safety notes are on the slides and in the Teacher Guide.
- Support is built in: word banks, sentence starters and support notes on the slides, plus GT extensions.
Standards
- NGSS MS-LS4-6: Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time. (Kentucky 8-LS4-6 uses the same wording.)
- SEP: Using Mathematics and Computational Thinking · DCI: LS4.C · CCC: Cause and Effect
- Stretch: HS-LS4-3
- CCSS connections: 6.RP.A.1, 6.SP.B.5, 7.RP.A.2, MP.4
Try the digital activity first
- Not sure the self-grading activity will work in your LMS? Download the FREE HTML & SCORM Sample and test it with your students before you buy.
Save with a bundle
- Genetics & Adaptation (5 sets)
- Middle School Life Science (21 sets)
- Science Unlocked Mega Bundle (all 89 sets)
Teach next
- The Bodybuilder Dog (MS-LS3-1)
- The Banana Clones (MS-LS3-2)
- Hurricane Survivors (MS-LS4-4)
- The Neon Fish (MS-LS4-5)
More from Mystery Lab Learning
- See every Science Unlocked set, and follow to hear when new ones are added, at Mystery Lab Learning.
Good to know
- The illustrations in this resource were created with AI image tools, and AI tools helped draft the lesson text. Every slide, answer key and lab step was then fact-checked against the sources listed in the Teacher Guide and proofread.
- Kahoot!, Blooket, Jeopardy!, Google Slides and PowerPoint are trademarks of their owners. This resource is not affiliated with or endorsed by them.
- License: one teacher, for use with their own students. Please buy an additional license for each colleague who uses it.
