In this unit about genetic variation, learners help Mosa solve the mystery of why some organisms have identical offspring and others have offspring that exhibit variation. Through the mystery as well as a hands-on modeling activity, learners will discover that organisms can reproduce sexually or asexually, leading to different amounts of genetic variation. After learners fully understand both reproductive processes and their results, they genetically engineer a solution to a hypothetical alien problem.
Learners help Mosa solve the mystery of why the algae siblings look identical while the frog sisters look so different. Students discover that unlike asexual reproduction, offspring derived from sexual reproduction receive half their DNA from mom and half their DNA from dad, which causes them to have genetically different traits from their parents and siblings. (80 minutes)
Learners engage in the hands-on modeling activity of creating two alien families: one that produces asexually and one that produces sexually. (150 minutes)
Building off the “Make,” learners genetically engineer a solution to a hypothetical alien problem. Learners use scientific reasoning to justify the ideal parent genetic combination for their chosen trait (150 minutes)
Next Generations Science Standards
- Develop and use a model to describe why asexual reproduction results in offspring with identical genetic information and sexual reproduction results in offspring with genetic variation.
- Gather and synthesize information about the technologies that have changed the way humans influence the inheritance of desired traits in organisms.
Science & Engineering Practices
- Developing and Using Models
- Obtaining, Evaluating, and Communicating Information (Oral Presentation)
Disciplinary Core Ideas
- Inheritance of Traits
- Natural Selection
- Variation of Traits
Cross Cutting Concepts
- Cause and Effect
- Connections to Engineering, Technology, and Applications of Science
- Connections to Nature of Science
- Interdependence of Science, Engineering, and Technology
- Science Addresses Questions About the Natural and Material World
- Each lesson in the unit has an Inquiry Scale that provides directions on how to implement the lesson at the level that works best for you and your students.
- “Level 1” is the most teacher-driven, and recommended for students in 4th-5th grades. “Level 4” is the most student-driven, and recommended for students in 7th-8th grades.
- For differentiation within the same grade or class, use different inquiry levels for different groups of students who may require additional support or an extra challenge.
- Learners can be confused by the idea of genes coding for proteins which determine traits because they have only heard the word protein in the context of food. Highlight that the protein in the food we eat is broken down into smaller parts called amino acids. Those amino acids are then used as building blocks for this process.
- Learners are initially uncertain about the difference between a gene and a trait, so take time to highlight this both in the episode and the vocabulary mind map before moving on to the “Make.”
- Learners at first believe that if the offspring have a physical trait in common with one parent, that trait comes wholly from one parent. Emphasize that offspring get half their DNA from mom and half from dad, and this applies to every trait. It is helpful to scaffold this during the “Make” by showing one allele coming from mom and one from dad to create the trait in the offspring.
- Asexual Reproduction
- Sexual Reproduction
- Bruce Grant, Ph.D
Professor of Biology Emeritus; College of William & Mary
- Powerpoints for Make and Design
- Vocabulary Cards
- Solve Student Handout
- Make Student Handout
- Design Student Handout
- Vocabulary Mind Map