L07 — The Big Picture

Module: M07 — The Arms Race Periods: 1 NGSS: HS-LS4-1, HS-LS4-2, HS-LS4-4, HS-LS4-5 Lesson Type: Evaluate

Learning Objective

By the end of this lesson, students will be able to apply the natural selection framework (variation, inheritance, selection pressure, differential reproduction) to a novel organism and environment they have not previously studied, demonstrating transfer of the core mechanism across contexts.

Phenomenon / Hook

“Over the past 6 lessons, we’ve seen natural selection in bacteria, moths, finches, swallows, and in our own simulations. Today, you get a new organism you’ve never seen before. Your job: figure out how natural selection shaped it.”

Display 3–4 images of unfamiliar organisms with unusual adaptations: the star-nosed mole, the axolotl, the bombardier beetle, the tardigrade. “Which of these evolved through natural selection? All of them. But how?”

Materials

Novel organism cards (one per group): [[handouts/L07-novel-organism-cards]] — each card describes an organism, its environment, and a key trait
Four Conditions framework sheet (blank — students fill in)
Chart paper and markers for presentations
Module self-assessment rubric

Agenda

Opening (5 min)

Display novel organism images (2 min)
Quick review: “Without looking at your notes — what are the four conditions of natural selection? Shout them out.” (1 min)
Set expectations: “Today you apply everything you’ve learned to something new. No notes during the main activity. This is your chance to prove you own this concept.” (2 min)

Explore (18 min)

Novel Organism Challenge (groups of 3–4)
- Each group receives a card describing an organism they haven’t studied:
  - Organism A: Rock pocket mouse — lives on dark lava flows in New Mexico. Most are light-colored, but populations on dark rock are nearly black. Owls are the main predator.
  - Organism B: Ethiopian wolf — lives in high-altitude grasslands. Has a narrow, elongated snout. Preys on rodents that live in deep tunnels.
  - Organism C: Arctic fox — changes coat color from white (winter) to brown (summer). Lives in tundra where snow cover changes seasonally.
  - Organism D: Caribbean anole lizards — on different islands, have evolved different toe pad sizes to grip different surface types (smooth leaves vs. rough bark).
- For their organism, groups must:
  1. Identify the four conditions of natural selection (fill in framework sheet)
  2. Describe the selection pressure
  3. Explain why the trait is adaptive in this specific environment
  4. Predict: what would happen if the environment changed? (e.g., lava flow cools and turns gray; climate warms and snow melts earlier)
  5. Connect: how is this the same as one case we studied in L01–L06?
- Groups prepare a 2-minute presentation on chart paper

Explain (12 min)

Group Presentations: Each group presents their organism (2 min each, 4 groups)
After each presentation, class gives a thumbs up/down: “Did they correctly apply all four conditions?”
Teacher fills gaps with targeted feedback:
- Common errors: confusing inheritance with “learning,” describing selection pressure vaguely, forgetting differential reproduction
- Strong connections: “Group C connected the Arctic fox to the peppered moth — both change color to match their environment. Great transfer.”
Module Synthesis: On the board, draw a concept map linking all 7 lessons:
- L01: Mechanism (four conditions)
- L02: MRSA (antibiotic resistance)
- L03: Peppered moths (camouflage + pollution)
- L04: Finches (beak shape + food)
- L05: Arms race (predator-prey speed)
- L06: Cliff swallows (human infrastructure)
- L07: Novel organisms (transfer)
- Arrow connecting all: SAME MECHANISM, DIFFERENT CONTEXTS

Elaborate (8 min)

Module Reflection: Individual written reflection (5 min):
1. Which example from this module was most surprising to you? Why?
2. What is one misconception you had at the start of this module that you’ve corrected?
3. How does natural selection connect to genetics (M05) and gene editing (M06)?
Transfer Task Preview: Introduce the Pick Your Path transfer task. Students choose Write/Design/Debate and begin brainstorming (3 min).

Closing (3 min)

Exit Ticket: [[exit-tickets/L07-exit-ticket]]
1. You discover a population of frogs in a polluted pond. Over 10 years, the frogs develop thicker skin. Is this natural selection? Explain using the four conditions.
2. Why is it important that evolution has no “goal”? What would be different if organisms could choose their adaptations?

Differentiation

Support	Extension
Provide a partially completed framework sheet with the organism and trait pre-filled — students identify selection pressure and differential reproduction	Ask: Choose any organism you’re curious about. Research one adaptation and explain it using the four conditions. Present to class tomorrow for extra credit.
Allow groups to use notes for the first 5 minutes of the Explore phase, then close them	Challenge: Create a “misconception buster” poster for natural selection — list 5 common misconceptions and the correct explanations.

Assessment

Formative: Group presentations — assess accurate application of four conditions to novel organism
Exit Ticket: Novel scenario application + conceptual reflection
Summative: Transfer task (due next class or as homework)

Teacher Notes

The “no notes” rule during the main activity is intentional — it forces retrieval practice. If students panic, allow 2 minutes of note review at the start, then close them.
The novel organisms are chosen to be unfamiliar but not obscure. If students happen to know one, swap it out — the point is transfer to new contexts.
The module synthesis concept map is powerful for visual learners. Keep it on the board through the transfer task due date.
The reflection questions connect M07 back to M05 (genetics) and M06 (CRISPR) — this is intentional continuity. Students should see evolution as the consequence of genetics: mutations create variation, inheritance passes it on, natural selection shapes populations.
If time allows, the “misconception buster” extension makes a great hallway display.