The Great Candy Creature Evolution Challenge

Materials Needed:

• For the Creature:
  • A variety of candies and craft materials (e.g., gummy bears for the body, mini marshmallows for feet, toothpicks for legs/arms, licorice strings for tails, M&Ms or sprinkles for eyes, gumdrops for heads).
  • Paper plates or a clean workspace to build on.
• For Simulation & Recording:
  • Notebook or paper for recording data.
  • Pencil or pen.
  • One six-sided die.
  • A small bowl or cup.
• Optional (for Extension):
  • Graph paper.
  • Calculator.

Lesson Details

Subject: Science (Biology, Genetics, Evolution)

Grade Level: Middle School (Ages 11-13)

Time Allotment: 90 minutes

Learning Objectives

By the end of this lesson, the student will be able to:

1. Model how a structural change to a "gene" (a candy part) can alter a "protein" (the creature's structure) and result in a beneficial, harmful, or neutral trait.
2. Explain how a mutation can affect an organism's ability to survive and reproduce in a specific environment.
3. Use simple mathematical representations (counts and percentages) to track and explain how natural selection causes the frequency of a specific trait to increase in a population over several generations.
4. Apply concepts of probability (using a die roll) to explain how variation is introduced into a population.

Standards Addressed (NGSS)

• LS3.B (Variation of Traits): Develop and use a model to describe why structural changes to genes (mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.
• LS4.B (Natural Selection): Use mathematical representations to support explanations of how natural selection may lead to increases and decreases of specific traits in populations over time.
• LS4.C (Adaptation): Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population.

Lesson Sequence & Instructional Activities

Part 1: The Spark - Introduction (10 minutes)

Goal: Activate prior knowledge and set the stage for the activity.

Instructions:

1. Begin with a conversation. Ask questions like:
   • "Think about a recipe for a cake. What happens if you change one ingredient—like using salt instead of sugar? The recipe is like an organism's genes, and the final cake is like the organism."
   • "What are some traits that help animals survive in the wild? (e.g., camouflage, speed, sharp claws)."
   • "Today, you are going to be a scientist who discovers a new species of 'Candy Creature.' You will get to see what happens when its 'recipe' or genes change, and how it survives in a changing world."

Part 2: Build-A-Creature - Modeling Genes and Traits (15 minutes)

Goal: Create a physical model of an organism with distinct traits determined by "genes."

Instructions:

1. Lay out all the candy and craft supplies.
2. Task: Build your "founder" Candy Creature. This is Generation 1.
   • Use one type of candy for each body part (e.g., gumdrop head, gummy bear body, toothpick legs, licorice tail).
3. In your notebook, create a "Creature Profile" chart. Record the "gene" (the candy part) and the "trait" (what the part does).
   Example Chart:

   Gene (Candy Part)	Trait (Structure & Function)
   Gumdrop	Head - Round, for 360-degree vision.
   Toothpick	Legs - Short, makes the creature stable but slow.
   Mini Marshmallow	Feet - Soft, for silent movement.

Part 3: The Mutation Station - Modeling Gene Mutations (15 minutes)

Goal: Model how random mutations can change an organism's traits and evaluate the effect.

Instructions:

1. Task: Let's see if your creature has a mutation! Roll the six-sided die.
   • Roll a 1 or 2: A mutation occurs! Go to the next step.
   • Roll a 3, 4, 5, or 6: No mutation. The creature is a perfect copy of its parent. (This demonstrates that mutations are relatively rare).
2. If a mutation occurred, roll the die again to determine which "gene" is affected. Assign a number to each body part on your Creature Profile (e.g., 1=Head, 2=Legs, etc.). Swap the original candy part for a different one.
3. Analyze the Mutation: In your notebook, describe the change. Then, decide if the mutation is beneficial, harmful, or neutral in a "normal" environment. Justify your answer.
   • Example: "My creature's toothpick legs (short) mutated into licorice legs (long and wobbly). This is harmful because now the creature is unstable and might fall over easily."

Part 4: Survival of the Sweetest - Simulating Natural Selection (35 minutes)

Goal: Use a simulation and simple math to show how natural selection drives changes in a population over time.

Instructions:

1. Create the Population: Start with a population of 10 Candy Creatures. For this simulation, let's focus on one trait: leg length. Make 8 creatures with short toothpick legs and 2 with long licorice legs. This is your Generation 1 population.
2. Introduce Environmental Pressure: Announce the new environmental condition: "A terrible flood has occurred! The ground is now covered in 1 inch of water. Only creatures with long legs can keep their bodies dry and survive to reproduce."
3. Apply Natural Selection:
   • Which creatures survive? (The ones with long licorice legs).
   • The creatures with short toothpick legs are "eliminated" (you can eat them!).
4. Track the Data: In your notebook, create a data table to track the population over generations.
   Example Data Table:

   Generation	Total Population	# with Short Legs	# with Long Legs	% with Long Legs
   1	10	8	2	20%
   2
   3

5. Reproduce and Introduce Variation: The surviving creatures reproduce. For each survivor, add 4 new offspring to the population. These offspring will have the same traits as the parent (long legs). However, for each new offspring, roll the die to see if a random mutation occurs (a roll of 1 = mutation to short legs). This keeps variation in the population.
6. Repeat for Generations 2 & 3: Repeat the process—apply the "flood" pressure, eliminate those that don't survive, reproduce, and record your data. Calculate the percentage of the population with long legs each time.

Part 5: Wrap-Up & Assessment (15 minutes)

Goal: Synthesize learning through creative application and discussion.

Instructions:

1. Discussion: Look at your data table. Ask:
   • "What happened to the percentage of creatures with long legs over time? Why did this happen?"
   • "What do you think would happen if the environment changed again, and being short was now an advantage (e.g., a new predator that can only see tall things)?"
   • "Was the long-leg mutation 'good'? (Guide the student to understand it was only 'good' or 'beneficial' in that specific environment)."
2. Creative Assessment: Naturalist's Journal Entry
   • Prompt: Write a one-paragraph journal entry from the perspective of a scientist discovering the Candy Creature. Describe your original creature, the mutation that occurred in its offspring, why that mutation was so important for survival during the "great flood," and how the entire species looked different after just a few generations.
   • This assesses all the learning objectives in a creative, low-pressure format.

Differentiation & Extension

• For Support:
  • Provide a pre-printed data table and Creature Profile chart.
  • Work together to calculate the percentages.
  • Provide sentence starters for the journal entry, such as: "My first observation was of a creature with... A mutation caused... When the environment changed, this trait was beneficial because..."
• For Challenge:
  • Introduce a second environmental pressure that affects a different trait simultaneously (e.g., "the flood" and "only creatures with M&M eyes can see the food").
  • Have the student create a line graph showing the change in the percentage of the long-leg trait over generations.
  • Ask the student to calculate the probability of a specific double mutation occurring (e.g., long legs AND a new mouth type).