Unit Plan 21 (Grade 7 Science): Genetic Variation
Grade 7 unit comparing genetic variation in asexual and sexual reproduction—students model cloning vs. mixed gene combinations to explain identical vs. varied offspring.
Focus: Compare genetic variation in individuals produced by asexual vs. sexual reproduction, using models to show why asexual reproduction leads to identical genetic information while sexual reproduction leads to variation.
Grade Level: 7
Subject Area: Science (Life Science — Inheritance & Variation)
Total Unit Duration: 5 sessions (one week), 50–60 minutes per session
I. Introduction
In this unit, students zoom out from individual genes to look at variation within populations. They explore how offspring from asexual reproduction tend to be genetically identical to the parent (and one another), while offspring from sexual reproduction show a range of differences in traits. Through models, data tables, and simple simulations, students compare “cloned” populations (asexual) with “sibling” populations (sexual) and explain how differences in reproduction lead to differences in genetic variation, aligned with MS-LS3-2.
Essential Questions
- How does asexual reproduction affect variation among offspring compared to sexual reproduction?
- Why do many asexually produced individuals look almost identical, while sexually produced offspring show more variation?
- How can models and simulations help us compare patterns of variation in asexual vs. sexual populations?
- Why does genetic variation matter for populations over time?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Define genetic variation and identify examples of variation in observable traits within a population.
- Use models to describe why asexual reproduction produces offspring with identical genetic information (barring rare mutations) and therefore lower variation.
- Use models to describe why sexual reproduction mixes genes from two parents, producing offspring with different combinations of genetic information and therefore greater variation.
- Collect and analyze class data from asexual vs. sexual reproduction simulations to compare patterns of variation (e.g., number of trait combinations, frequency of each type).
- Create a final Genetic Variation Comparison Model & Explanation that clearly compares asexual vs. sexual reproduction and explains why one leads to identical genetic information while the other leads to variation, aligned to MS-LS3-2.
Standards Alignment — 7th Grade (NGSS-based custom)
- MS-LS3-2 — Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information while sexual reproduction results in offspring with genetic variation.
- Students build and analyze models for asexual “clones” vs. sexual “siblings” in simulated populations.
Success Criteria — Student Language
- I can define genetic variation and point out examples of variation in traits.
- I can use a model to show how asexual reproduction copies identical genetic information into offspring.
- I can use a model to show how sexual reproduction mixes genetic information from two parents, creating different gene combinations.
- I can use data from our simulations to show that asexual populations tend to have less variation and sexual populations have more variation.
- I can create a final explanation that clearly states why asexual reproduction leads to identical genetic information and sexual reproduction leads to variation, using correct vocabulary.