Unit Plan 6 (Grade 7 Science): Growth & Cell Division
Grade 7 unit where students use data and models to show organisms grow through cell division, constructing evidence-based arguments aligned to MS-LS1-4.
Focus: Support claims that biological growth occurs through cell division, using data, models, and evidence from living organisms.
Grade Level: 7
Subject Area: Science (Life Science — Cells & Growth)
Total Unit Duration: 5 sessions (one week), 50–60 minutes per session
I. Introduction
In this unit, students connect their understanding of cells and body systems to the idea that organisms grow because cells divide, not because existing cells just get bigger and bigger. Through time-lapse images, simple growth investigations (e.g., plant seedlings, yeast, or brine shrimp), slides or diagrams of dividing cells, and data analysis, they gather empirical evidence and practice scientific reasoning. By the end of the week, students construct an argument aligned to MS-LS1-4 that biological growth is the result of cell division.
Essential Questions
- What does it really mean for a living thing to grow?
- How does cell division contribute to growth in plants and animals?
- What kinds of evidence can we collect to show that growth comes from more cells, not just bigger cells?
- How can we use data, models, and reasoning to support a scientific claim about growth?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Describe growth in living things at both the organism level (height, mass, size) and the cell level (increase in number of cells).
- Analyze data sets, images, or time-lapse sequences showing cell division (e.g., root tips, embryos, tissue growth) and connect them to overall growth.
- Develop and use models (diagrams, sequences, and simple bar graphs) to show how repeated cell division increases cell number.
- Distinguish between growth by cell enlargement and growth by cell division, using evidence to determine which explanation fits better.
- Construct a claim–evidence–reasoning (CER) argument, based on empirical evidence and scientific reasoning, that biological growth is the result of cell division, aligned to MS-LS1-4.
Standards Alignment — 7th Grade (NGSS-based custom)
- MS-LS1-4 — Use argument based on empirical evidence and scientific reasoning to support the claim that biological growth is the result of cell division.
- Students collect or analyze growth data, examine cell division evidence, and argue that growth involves increasing numbers of cells.
Success Criteria — Student Language
- I can describe growth in terms of more cells, not just bigger cells.
- I can interpret data and images that show cell division in growing organisms.
- I can create a model that shows how repeated cell division increases the number of cells.
- I can explain why cell division is a better explanation for growth than “cells just get huge.”
- I can write a CER that uses evidence and reasoning to support the claim that biological growth is the result of cell division.