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AP Biology · Unit 3 · Evolution and Natural Selection · Lab

The Shmoigle Hunt

A blanket, a hippo, three colors of Shmoigle, and a utensil. Fifteen seconds a hunt. By the end of four generations you will have made a population evolve with your own hands, and you will have the numbers to prove it. Every rule in this game is one sentence from the Unit 3 strategy page turned into something you can touch.

Why this lab comes first in the unit

Most of the traps in Unit 3 are sentences that give an organism a goal: the moths turned dark, the bacteria learned to resist, each finch grew a deeper beak. Those sentences feel right because we are used to stories with characters who want things. The Shmoigle Hunt is a story with no characters. Nothing on the blanket wants anything. Nothing on the blanket changes. And the population evolves anyway, in four generations, on a timer.

Once you have watched that happen, the Lamarckian sentence stops sounding right. That is the point.

The simulation

Play the Shmoigle Hunt

Your progress saves in this browser between generations. If the game feels cramped, open it full screen. Open the game full screen ↗

Works with a mouse, a trackpad, or a finger. Press and hold on the blanket to pick up your utensil, drag over a Shmoigle to catch it, then carry it across the dashed line to the hippo before the clock runs out.

How to run it

The Procedure

Work in groups of two to four. Each group is one utensil population: everyone in your group hunts with the same utensil for the whole lab. Your teacher will assign utensils so the class has spoon groups, fork groups, and knife groups.

HunterTakes the timed turns. Rotate who goes first each generation so everyone hunts.

RecorderCopies the generation row into the shared sheet before the next generation starts.

CheckerReads the mathing out loud and confirms it matches the rules below before anyone clicks Next.

PredictorBefore each hunt, writes down which color will be caught most and least, and why.

Run it in this order

Set up. Pick your assigned utensil. Leave the blanket on white for your first run. Leave the starting counts at 15 black, 15 white, 15 red. Open Rules of the mathing and set Most hunters per group to the number of people in your group; leave every other rule at its default. Every group starts generation 1 with a single hunter. Your population grows only if you catch enough.
Predict. Predictor writes a prediction for generation 1. Which color is easiest to see on a white blanket? Which is hardest?
Hunt. Each living hunter gets one 15 second turn. Catch as many Shmoigles as you can and feed them to the hippo. In generation 1 that is one turn; as the utensil population grows, the game tells you when to hand off to the next person.
Do the mathing. Read the results panel with the Checker. Confirm: survivors doubled, hunters sustained or starved, carrying capacity applied if needed.
Record. Recorder opens the data panel and uses Copy table for the shared sheet, then pastes into your group's rows of the class data sheet. The columns match exactly.
Repeat for generations 2, 3, and 4. Rotate the hunter. Predict every time; your predictions should get better as the survivors get warier.
Second run (if time). Reset, switch the blanket to red, keep the same utensil, and run four more generations. Record these as a separate run.

What counts as data The only numbers that matter are in the log table: start counts, caught counts, and next generation counts for each color, plus hunters before and after. Everything you will be asked to explain comes from those columns. The verdict text is a summary, not the data.

Do not edit the rules on the first run The default rules (15 second hunts, 3 Shmoigles to sustain a hunter, 6 per new hunter, a blanket that holds 240, wariness up to level 3) are what make the class data comparable across groups. The one setting you do change is Most hunters per group, which is just your group size. If your group wants to test a rule change, do it as a separate run after the standard one and label it in the sheet.

The model, stated plainly

What the Game Actually Does

You should be able to reproduce every number the game shows you by hand. Here are the rules it follows between generations.

Every Shmoigle that is not caught survives. Survivors of each color are counted separately.
Survivors double. 10 white survivors become 20 white Shmoigles next generation. Offspring are the same color as the parent, always.
The blanket holds 240. If doubling would push the total past 240, every color is scaled down by the same fraction so the total fits. Proportions are preserved; only the total is capped.
Each hunter needs 3 to survive. Total caught ÷ 3, rounded down, is how many hunters survive (up to the number you have).
Every 6 caught makes a new hunter. Total caught ÷ 6, rounded down, is how many hunters are born. Survivors plus born is next generation's hunters, capped at the size of your group.
Survivors get warier. Generation 1 Shmoigles drift and do not run. From generation 2, Shmoigles scoot away from the utensil, one level stronger each generation up to level 3.

Check yourself: if your 2 hunters catch 11 Shmoigles in generation 2 and your group has 3 people, how many hunters are there in generation 3? (11 ÷ 3 = 3, but only 2 were hunting, so 2 survive; 11 ÷ 6 = 1 born; 2 + 1 = 3, which fits your group of 3.) If 14 of 30 white Shmoigles were left after the hunt, how many white are there next generation? (28.)

The connection

Every Rule Is a Unit 3 Concept

The numbers in the Unit 3 column point to the 15 concepts on the strategy page. When you can explain a game rule in the language of the concept, you can answer the exam question about it.

What the game does	What it is modeling	Unit 3
Three colors on the blanket from the start, before any hunting	Variation exists first. The population had black, white, and red before any utensil touched it. Selection did not create the colors; it could only act on the ones already there.	46
Survivors double every generation; the blanket holds 240	Overproduction and carrying capacity. Left alone, the population would grow without limit. Resources (blanket space) cap it. That gap between how many are born and how many can live is what makes selection inevitable: Darwin's second condition.	4
Some colors are easier to see on a white blanket than others	Differential survival. Red and black Shmoigles on a white blanket get caught more. Camouflaged Shmoigles survive more. Not because they are better in any general sense; because of this blanket, with this predator.	46
Offspring are always the same color as the parent	Heritability. The trait that affected survival is passed on. Without this rule, the next generation would reset to 15/15/15 and nothing could evolve. This is the condition Lamarck's blacksmith fails: the muscles were not heritable.	34
The fraction of white Shmoigles rises across four generations	Microevolution. Evolution is a change in the frequency of a heritable trait in a population over generations. Your log table is a direct measurement of it. Note what did not happen: no Shmoigle changed color. The population changed; individuals did not.	912
Switching the blanket from white to red flips which color survives	The environment decides what is adaptive. White was the best color on the white blanket and the worst on the red one. "Fit" is never a property of the trait by itself. The rock pocket mice on the lava flow are this rule with fur.	67
Hunters survive at 3 caught and reproduce at 6 caught	Fitness is reproductive success. The utensil populations are evolving too. A spoon group that catches 5 per hunter survives but does not grow; a fork group that catches 12 per hunter grows. Fitness is counted in new hunters, not in how hard anyone tried.	5
Spoon, fork, and knife groups get different results on the same blanket	Predator traits are under selection as well. Compare the class data by utensil. If knives consistently out reproduce spoons, that is directional selection on the predator population, and the prey population changes differently under each predator.	7
With only 15 of a color, one lucky or unlucky hunt swings the frequency a lot	Genetic drift in small populations. If a hunter happens to catch 6 red and 0 black, red's share drops hard whether or not red was easier to see. Small numbers make chance loud. Compare generation 1 (45 total) with generation 4 (up to 240) and notice which one jumps around.	11
A color can hit zero and never come back	Loss of variation, and local extinction. Once a color is gone, doubling cannot restore it and there is no mutation and no migration to bring it back. This is why Hardy Weinberg requires a large population: so chance cannot delete an allele.	111215
Survivors from generation 2 on scoot away from the utensil	A second trait under selection, and a model's shortcut. Wariness rising in survivors looks like a behavior being selected for. But in the game every survivor gets warier automatically, which is closer to Lamarck than Darwin. Real wariness would have to vary first, be heritable, and be selected. Say so in your analysis.	36

The sentence to practice After the lab, every student should be able to write this without help: "The frequency of white Shmoigles increased over four generations because white Shmoigles on a white blanket were caught less often, so a larger fraction of them survived to reproduce, and their offspring inherited their color. No individual Shmoigle changed color; the population's composition changed." That sentence has every clause an FRQ rubric looks for: variation, differential survival, a stated cause, heredity, and the population as the subject.

Be honest about the model

What the Shmoigle Hunt Gets Wrong on Purpose

The exam loves to ask what a model leaves out. This one leaves out plenty, and naming the gaps is worth more than pretending they are not there.

No mutation. No new color ever appears. In a real population, mutation is the ultimate source of new variation (Concept 10). The game can only lose alleles; it can never gain one.
No gene flow. Nothing arrives from another blanket. Real populations exchange migrants, which tends to make them more alike.
Reproduction is asexual and exact. Survivors double, offspring are clones. No meiosis, no crossing over, no independent assortment, no heterozygotes, no dominance. "White" here is a phenotype and an allele at the same time, which a real population never gives you. That is why your white fraction is not p or q; it is closer to a phenotype frequency with a one allele model.
Wariness is programmed, not inherited. Every survivor gets warier on schedule. Real behavior would vary among individuals and be selected like any other trait.
The predator never starves out the prey entirely, and the prey never fight back. No coevolution, no arms race beyond the scripted wariness.
Generations are instant and nonoverlapping. Real populations have parents and offspring alive at the same time, which smooths out the kind of swings you see in generation 2.

How to use this on the exam If a question asks you to "describe one limitation of the model" or "identify an assumption," any line above is a full credit answer, provided you say what the real process would do differently. "The model does not include mutation, so no new variation can arise; in a real population, mutation would eventually produce new color alleles" is the shape of the sentence.

Write it up

Analysis Questions

Answer from the class data sheet, not from memory of your own run. Use the strategy page's five moves: find the verb, decide what kind of answer it wants, and make the population the subject of your sentences.

1 · Describe For your group's first run, calculate the fraction of each color at the start of generation 1 and at the start of generation 4. State which color increased, which decreased, and by how much.

2 · Explain Explain the change you described in question 1 using all four conditions of natural selection. Each condition should be a separate sentence that names the game rule it corresponds to.

3 · Identify Did any individual Shmoigle change during your run? What, exactly, changed? Write one sentence that would be marked wrong on the AP exam about this lab, and then fix it.

4 · Compare Using the whole class's data, compare the white fraction at generation 4 across spoon, fork, and knife groups on the white blanket. Did the predator's utensil change how fast the prey population evolved? Propose a reason.

5 · Predict and justify If your group ran a fifth generation on the white blanket, predict the count of each color. Then predict what would happen to those counts if the blanket switched to red for generation 5 only, and justify using the idea that the environment determines which trait is adaptive.

6 · Evaluate Look at generation 1 to 2 in a group where one color fell to a small number. Was that change natural selection, genetic drift, or both? Describe what additional data would let you tell the difference.

7 · Hardy Weinberg A group reports 60 white and 40 nonwhite Shmoigles at the start of generation 4. A student says "so q = 0.40." Explain why that is not how Hardy Weinberg works, and what you would need to know about Shmoigle inheritance before you could use p and q at all.

8 · Hunters Plot hunters per generation for every group in the class. Which utensil populations grew, which held steady, which starved? Write a sentence about the fitness of each utensil that uses the word "fitness" correctly, meaning reproductive success and nothing else.

9 · Model limits Choose two of the limitations listed above. For each, describe one specific result in the class data that would probably look different if the model included that process.

10 · Extend Design a one rule change to the game that would let you test genetic drift separately from selection. State the rule, the prediction, and what result would support or refute the prediction.

Grading note Any answer whose subject is a Shmoigle (singular) and whose verb is "adapted," "evolved," "learned," or "became" loses the point. The subject is the population. The verb is "changed in frequency."

Now Read How the Exam Asks It

Every rule you just played is a sentence on the Unit 3 strategy page, and every trap on that page is a sentence this lab was built to make sound wrong.

Unit 3 strategy page Unit 3 practice quiz All units