Unit Plan 19 (Grade 4 Science): Plant & Animal Structures

Focus: Identify and explain how internal and external structures of plants and animals support survival, growth, behavior, and reproduction.

Grade Level: 4

Subject Area: Science (Life Science • Structure & Function)

Total Unit Duration: 5 sessions (one week), 50–60 minutes per session

I. Introduction

In this unit, students explore how living things are built for survival and growth. They observe and compare external structures (leaves, roots, teeth, claws, beaks, fur, shells) and internal structures (heart, lungs, stomach, skeleton) in plants and animals. Using pictures, models, and short texts, students connect each structure to a function, then use evidence to construct arguments about how structures help organisms get what they need, stay safe, and have offspring.

Essential Questions

• How do external structures (like roots, leaves, beaks, and fur) help plants and animals survive and grow?
• How do internal structures (like skeletons, hearts, and stomachs) support movement, protection, and getting energy?
• How can we use evidence from observations, diagrams, and reading to argue that structures help survival, behavior, and reproduction?
• Why is it useful for scientists, engineers, and doctors to understand how structure and function are related in living things?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Identify and describe external structures of plants and animals (e.g., roots, stems, leaves, beaks, claws, fur, shells) and explain how they support survival or growth.
2. Identify and describe internal structures of animals (e.g., skeleton, heart, lungs, stomach, brain) and connect each to its function.
3. Compare at least two different organisms, explaining how differences in structures relate to different habitats, behaviors, or diets.
4. Use observations, diagrams, and short texts as evidence to support a written or oral argument that structures support survival, growth, behavior, or reproduction.
5. Create a Structure & Function Evidence Poster or booklet that shows several structures and clearly argues how they help an organism survive.

Standards Alignment — 4th Grade (NGSS-Aligned)

• 4-LS1-1 — Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.
  • Example: Use evidence from diagrams and observations to argue how a cactus’s thick stem and spines help it live in a dry desert.

Success Criteria — Student Language

• I can point to and name important external structures on plants and animals and tell what each part does.
• I can describe internal structures (like heart, lungs, skeleton, stomach) and explain how they help the body move, breathe, or get energy.
• I can compare two organisms and explain how their structures fit their habitat and lifestyle.
• I can use pictures, models, and texts as evidence in my explanation or argument.
• I can create a clear poster or booklet that shows structures and explains how they help an organism survive and grow.