Explain Chromosomal Abnormalities and Crossing Over for High School Biology

Grade Levels
9th - 12th, Higher Education
Resource Type
Formats Included
  • PDF
7 pages
Share this resource


In your high school biology class, do you want to explain how cells get chromosome genetic abnormalities like deletion, duplication, inversion, and translocation? Do you want your students to be active in their learning and discover for themselves how crossing over during meiosis can go wrong? This is the lesson for you!

It is hard to visually explain how chromosomal abnormalities are formed and crossing over is also difficult to visualize for students. I normally use this lesson at the end of a mitosis/meiosis unit, after my students understand what the product cells form meiosis normally are, what homologous chromosomes are, and what the chromosomal abnormalities are (deletion, duplication, inversion, translocation).

In this lesson, your students will use colored pencils to trace over chromosomes and chromosomes with crossing over between them to let them separate out the meiotic products. My students love this lesson because it is a lesson where they can see for themselves how to produce the chromosomal abnormalities that cause so many human genetic disorders.

In this packet, I include a way to differentiate this lesson. For pages 4 and 5, the Mistakes in Crossing Over pages, I include 2 options. You can print pages 4a and 5a, which are easier and have the students analyze the diagram. Or you can print pages 4b and 5b (really pages 6 and 7) which require the students to produce part of the diagram and analyze it. In my college prep/lower level classes, I use pages 4a and 5a. In my honors or AP, I use pages 4b and 5b.


Page 1: Meiosis 1 and 2 Products

Page 2: Single Crossovers

Page 3: Double Crossovers

Page 4: Mistakes in Crossing Over #1 (deletions, duplications, chromosomes without centromeres or with 2)

Page 5: Mistakes in Crossing Over #2 (inversions, translocations)

Page 6: Optional Harder Page 4b

Page 7: Optional Harder Page 5b.

Page 8: Teacher Instructions

Page 9: Terms of Use

I designed this lesson to address Next Generation Science Standard*

HS-LS3-2: Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

Check out my Color-Your-Own Karyotype: An Independent Assortment Lesson!

If you would like colorful (or black and white) detailed karyotypes for quiz, poster, or PowerPoint diagrams, check out my Karyotype Clip Art Set!

Contact Us

If you have any questions or concerns, please reach out to us on the question and answer section of my store and we will get back to you quickly!

Terms of Use:

Purchasing my teaching resources allows you to:

* make copies for your own classes only.

* place this file on your own password-protected class page or server (Blackboard, Google Drive, etc) AS LONG AS no other teacher has access to that class webpage. This resource is for you, the purchaser, alone.

You are not allowed to distribute this digital resource to other teachers or post this resource on any webpage or server that is available for public view. If you and a team of teachers would like to use this resource together, please purchase additional licenses on the resource purchase page.

Failure to comply with these terms of use is a copyright infringement and a violation of the Digital Millennium Copyright Act (DMCA). Clipart and elements found in this PDF are copyrighted and cannot be extracted and used outside of this file without permission or license.

Files are partially or fully non-editable to protect the images that are copyrighted and purchased through licenses. Thanks for understanding!

© Bethany Lau 

All Rights Reserved.

*Next Generation Science Standards is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards was involved in the production of, and does not endorse, this product. (Disclaimer written and required by Next Generation Science Standards for all lessons sold that reference their name)

Total Pages
7 pages
Answer Key
Teaching Duration
45 minutes
Report this Resource to TpT
Reported resources will be reviewed by our team. Report this resource to let us know if this resource violates TpT’s content guidelines.


Questions & Answers

Teachers Pay Teachers is an online marketplace where teachers buy and sell original educational materials.

More About Us

Keep in Touch!

Sign Up