Unit Plan 16 (Grade 3 Science): Trait Variation & Survival

Focus: Explain how differences in traits (size, color, body coverings, behaviors) affect an organism’s chances of survival, finding mates, and reproducing.

Grade Level: 3

Subject Area: Science (Life Science)

Total Unit Duration: 5 sessions (one week), 45–60 minutes per session

I. Introduction

In this unit, students explore how variation in traits within a species (e.g., different beak shapes, fur thickness, camouflage patterns) can change how well organisms survive in their environments. Through stories, data sets, models, and simple simulations, they see that some trait combinations offer advantages in certain conditions while others do not. Students then use evidence from investigations and data to construct explanations for why some individuals survive and reproduce more successfully than others.

Essential Questions

• How are organisms of the same kind similar to and different from each other?
• How can trait differences (color, size, body covering, behavior) affect an organism’s ability to find food, stay safe, or have babies?
• How can evidence from models and data help us explain why some traits are more helpful in certain environments?
• Why is it important for scientists to study variation and survival in living things?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Identify and describe observable trait variations within a single species (e.g., different fur colors, beak shapes, plant heights).
2. Use models and simple simulations to show how certain trait variations can help or hurt an organism’s chances of survival in a particular environment.
3. Analyze and interpret data tables or graphs showing how many individuals with certain traits survive in different conditions.
4. Construct a written or oral explanation, using evidence, that connects trait variation to survival success (e.g., camouflaged animals are harder for predators to see).
5. Create a Trait & Survival Case Study (poster, booklet, or slide) that explains how one trait variation affects survival for a chosen organism.

Standards Alignment — 3rd Grade (NGSS-Aligned)

• 3-LS4-2 — Use evidence to construct explanations for how variations in traits affect ability to survive.
  • Example: Compare how many light vs. dark colored insects remain after a “predator search” on different backgrounds.

Success Criteria — Student Language

• I can name and describe at least two different traits in the same kind of plant or animal.
• I can use a model or game to show how a trait (like color or beak shape) can help an organism survive in its environment.
• I can read a simple chart or graph and tell which trait seems to help more organisms survive.
• I can explain my thinking with evidence: “Because of this trait, more organisms survived, so it helped them live and have babies.”
• I can create a Trait & Survival Case Study that clearly connects variations in traits to survival chances.