Unit Plan 11 (Grade 3 Science): Diverse Life Cycles

Focus: Compare amphibian, insect, mammal, bird, and plant life cycles to show that all organisms move through birth, growth, reproduction, and death, but with unique patterns (e.g., metamorphosis).

Grade Level: 3

Subject Area: Science (Life Science)

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

I. Introduction

Students zoom in on diverse life cycles by studying frogs, butterflies, birds, mammals, and flowering plants. Through diagrams, videos, and card sorts, they notice which organisms have metamorphosis, which do not, and how each still follows the same overall pattern: birth → growth → reproduction → death. By the end of the week, they create a comparison model that shows both similarities and differences among these life cycles.

Essential Questions

• How are life cycles of frogs, butterflies, birds, mammals, and plants similar?
• How are their life cycles different, especially in how they grow and change?
• What does metamorphosis mean, and which organisms go through it?
• Why is it important for scientists and citizens to understand life cycles of living things?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Identify key life cycle stages (birth, growth, reproduction, death) for at least four different organisms (frog, butterfly, plant, bird, mammal).
2. Use diagrams and models to show how some organisms undergo metamorphosis (e.g., egg → larva → pupa → adult) while others grow more gradually.
3. Compare and contrast two life cycles using a Venn diagram or table, naming at least one similarity and one difference.
4. Explain in their own words that life cycles are diverse but patterned, and all organisms must grow and reproduce to keep their kind going.
5. Create a Diverse Life Cycles Comparison Poster that accurately models multiple life cycles and uses clear labels and explanations.

Standards Alignment — 3rd Grade (NGSS-Aligned)

• 3-LS1-1 — Develop models to describe that organisms have unique and diverse life cycles, but all have birth, growth, reproduction, and death.
  • Example: Draw and label life cycle diagrams for a frog, butterfly, and bean plant, then explain how they are alike and different.

Success Criteria — Student Language

• I can name and draw the main life cycle stages of frogs, butterflies, plants, birds, and mammals.
• I can explain what metamorphosis means and give at least one example of an animal that has it.
• I can use a chart or Venn diagram to show how two life cycles are alike and different.
• I can create a poster or model that correctly shows more than one life cycle with clear labels.
• I can explain that all living things have birth, growth, reproduction, and death, even if their life cycles look different.