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middle school science

Your Tried and True Strategy to Teach and Troubleshoot Punnett Square Examples

punnett-square-examples-blog

As soon as I start my heredity unit with my middle school students, someone asks the question, “Why do I have blue eyes and both of my parents have brown eyes?” Without fail. It’s not a super simple answer when they’re just learning about heredity. Students have to learn how to complete a Punnett square. I am always so excited to show them Punnett square examples of how this eye color phenomena actually happens!

Some kids really get it and others looked at me like I am an alien. It took a couple years for me to realize teaching Punnett Squares can be tricky because they seem so simple. When I really took a look at why some kids were struggling, I realized Punnett squares are a little more complex that I originally thought.

So many things that can go right and wrong. Even kids who complete the Punnett square correctly don’t always know what the information is trying to tell them. So let me help walk through a few tips and tricks that have helped me! 

What Are Punnett Squares?

punnett-square-examples

Punnett squares are a diagram showing us all the possible genetic combinations of offspring created by two parents for a specific trait. In other words, it helps us predict the likelihood offspring will have specific traits. Can two parents with brown eyes really have offspring with blue eyes? Simply, yes. Getting kids to the place where they can answer this on their own takes a bit of work.

The Secret Sauce to Students Getting It

There’s a strategy to teaching Punnett squares in a way that makes sense to your students. The last thing you want to do is start by working through several Punnett square examples. Although this works in theory, there’s a lot of background students need to complete and collect information from Punnett squares.

Focus on Vocabulary!

Do not skip this! Kids need to know a lot of vocabulary to learn Punnett squares well. Strong vocabulary knowledge gives students the ability to set up simple and complex Punnett squares and the understanding they need to analyze the information they find. 

I’d suggest teaching the words trait, offspring, allele, dominant, recessive, homozygous, heterozygous, dominant, recessive, genotype, and phenotype. 

Spending time on this vocab will result in stronger science students who are ready for high school! 

Don’t be the teacher who moves right from vocabulary to Punnett square examples. There are so many small mistakes students can make that will really throw them off later, but being able to make sense of Punnett squares in their head before you actually teach it helps so much! Click here to find this investigation and more resources to teach Punnett squares!

Be intentional about Punnett Square Practice Problems

From setting up Punnett squares to analyzing what kind of information they’re telling us, be intentional about how you work through Punnett square examples. Scaffold each step and be sure your students are ready to move on before introducing the next skill. Don’t just give them Punnett Square practice worksheets. Guide them through every step.

Punnett Square Setup

I’m going really elementary here. Ready? Draw a square and then, starting in the middle and a little bit above the top, draw one line vertically separating the square into two equal rectangles. Next, starting a little to the left and in the middle, draw a line horizontally. This creates four smaller boxes and splits both the top and the left side into two sections as well. 

One set parent allele goes on the top; one letter above each box in the outside spaces. The other set of parent alleles goes on the left side; one to the left of each box in the outside spaces.

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How Do You Do Punnett Squares?

Each one of the parent alleles on the top of the Punnett square falls and is written into the two boxes below it. Then, each letter from the side scoots over and is written in the two boxes to the right. It’s kind of a drag and drop. 

Your capital letter is the dominant allele and the lowercase letter is the recessive allele.

Another great way to explain this is to tell students to think of it as the distributive property in math. When you have 2(4x+y), you distribute the 2 outside of the parentheses into the 4x and the y. This turns into 8x+4y. Students distribute the letter outside of the Punnett square, the parent allele, into each box. You can see this in the color coded GIF!

Be sure to tell students the capital letter always is first in an allele pair. No matter what. 

So, What Do Punnett Squares Actually Say?

Once we’ve ended up with two alleles, one from each parent, in each box and completed the Punnett square, we can answer the question: what are Punnett squares? These alleles are the possible allele combinations, or genotypes, the offspring can inherit from the parents. 

how-to-do-a-punnett-square

Genotypes are different from phenotypes. Genotypes are the allele combinations, while phenotypes are the physical expression of those alleles. While a Punnett square can have BB, Bb, and bb genotypes, it only shows physical expression of brown and blue eyes. 

The example we walked through shows you why vocab is so important! Students really need to know how all these words work together in order to complete and draw information from Punnett squares.

Kids Still Struggling? Here’s some troubleshooting help!

While students are working, pay attention to what they’re doing. It’s easy to sit and grade or answer emails. Don’t do it! Until your kids have a good understanding, walk around, check work, and correct as needed. I explain how why scaffolding is so important in my blog post Five Easy Tips To Teaching Heredity In Middle School.

These are some issues I’ve run into while teaching Punnett square examples and how to remedy them.

Punnett-square-practice-worksheets-bundle
Get seven full days of no-prep lessons to use in your middle school classroom so you can save time and energy planning your Punnett Square unit!

Students only put one allele inside of each box.

It’s possible that there was some miscommunication (or not listening) when students were learning where to place alleles on the Punnett square. If you see this with a few kids, pull them over and reteach or do a few more examples. If you see this a lot, reteach everyone. Do more examples together. Employ the I do, we do, you do strategy. Use whiteboards (maybe even in pairs) for quick checks. Make practice stations where struggling students can work with and listen to conversations their peers are having.

Students don’t know how to analyze a Punnett square.

For whatever reason, teaching how to read and analyze a Punnett square is overlooked. Be sure to scaffold your Punnett square instruction. Complete a few simple Punnett squares, then ask what genotypes and phenotypes a few Punnett square examples show. Next, ask something like, “what percentage are heterozygous?” Or, “What is the possibility that the offspring will have freckles?” and specifically teach students how to find answers to those questions. We often forget that we’ve been doing this so long it’s easy! Students are brand new to this. Give them the proper support to be successful.

Students are just lost.

Remediate vocabulary! Punnett squares are so vocabulary heavy and kids really, really need to have a good grip on it. If you find most of your students are struggling overall, reteach vocabulary. Give each word hand gestures or have them create a game. If most of your students are lost, don’t push it. Go back and reteach, starting with vocab.

I’m a huge proponent of student investigation in science. I think it’s so valuable. But there’s also value in direct instruction. If your students are struggling, sometimes the best thing to do is just tell them what to do. I can set up the coolest investigations for seasons, moon phases, and tides, but at the end of the day, there will always be a kid who tells me the earth is flat. And you can let kids investigate Punnett squares, but you’ll still have to follow up by teaching some of the information directly. It’s okay to tell kids the right answer. 

Back to our question, can two parents with brown eyes really have offspring with blue eyes? Absolutely, they can! Don’t tell students though. Be intentional as you work through Punnett square examples with them. Then they’ll be able to find the answer out for themselves!

Life Science, Middle School

How to Use Picture Books to Teach Food Chains

pond-circle-food-chain-artwork

I remember the transition from picture books to “real” books. Somewhere between The Magic Treehouse series and Hatchet, the pictures slowly disappeared from the books I was reading. And while this is a totally good and normal process, there’s something exciting about opening a book and seeing pictures. So why wouldn’t we as teachers harness that nostalgia and use picture books in our teaching? This is my all time favorite list of picture books to teach food chains and food webs!

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The Case for Using Picture Books in your Middle School Classroom

Picture books are pretty simple on the outside. What makes them a powerful tool in your classroom is that simplicity. They’re not intimidating. Whether your students are high achievers or struggling learners, they love being read to. 

What I think I love most about using picture books to teach middle school science is that it has the ability to break down, and even scaffold, content and vocabulary that can initially be tough for kids to get the hang of. But with a guided read aloud, these science concepts can easily be highlighted by the teacher and are usually emphasized by pictures. 

Without further ado, these are my personal favorite best picture books to teach food chains and food webs!

Who Eats What? 

Who eats what picture book about food chains

The name says it all. This is a picture book about food chains and food webs. I love how simple this book starts and slowly scaffolds into complex food webs. The author really focuses on the complexity of a marine food webs about halfway through, including producers and consumers. The end of the book shares about how humans can impact food webs, using the example of otters killed for their fur.

If you use this picture book to teach food chains and food webs, ask students to make a venn diagram showing the differences and similarities. You can also ask students to compare and contrast  land and marine food webs.

Pond Circle 

This is one of my favorite picture books to teach food chains. While simple, there are a lot of different directions you can go with this book in a science classroom. We open up to algae in a pond, that is eaten by a mayfly, that is eaten by a beetle, who is eaten by a frog. The food chain continues. This picture book about food chains follows one very long chain all the way up to a coyote. 

If this book is about a pond food chain, how can it be so versatile? First, and very simply, it is a basic food chain. Talk about the idea of where each organism gets their energy and how long the food chain is. The raccoon eats owl eggs. Is that the same as eating an owl? Why or why not? 

My favorite way to incorporate this book is after we’ve learned about trophic levels. I read the book once, we talk about it, and then I ask them to make a trophic level pyramid using all the organisms from the book. I love hanging their trophic level pyramids on bulletin boards because they look so good! 

What’s for Dinner? Quirky, Squirmy Poems about the Animal World

whats for dinner picture book about food chains

What’s for dinner? Is a different book than the others. There are 29 short poems about food chains and food webs. The poems are witty, funny, informative, and right on with your middle school student’s humor! Trust me, they will love it. And while these poems are entertaining, this picture book teaches about food chains and food webs with great accuracy. 

This book is fun to use in stations or a carousel type of activity. Copy the poems you want to use and hang them around the room or set up stations. Create quick questions or activities based on the poems you choose. Students will LOVE this activity and learn some stuff too! 

Check out this free food chains and food webs silly story activity designed for middle school students!

Hey Diddle Diddle: A Food Chain Tale

hey-diddle-diddle-food-chain-picture-book

I really like this book to teach about food chains because it is just a funny story. Each one of the animals has a small part and something clever to say. This picture book about food chains highlights a couple of very small food chains with great images and catchy rhymes. I also enjoy that it includes a few lines about each animal’s adaptations. It’s a very fun and clever book.

Everything You Need to Know About Middle School Science in One Big Notebook

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Okay, this one isn’t exactly about food chains and food webs, but it sure is great! I use this book all the time. You’ll find every topic you’d ever need to teach about in middle school science in plain english for you or your students! I love copying this text to scaffold or accommodate for students. Each topic is written in a way that defines every word a student may not know and includes so many pictures. There is a whole section in this picture book about Interdependence and the Cycling of Energy and Matter, which is exactly where you’ll find all your information on food chains and food webs. 

There you have it. My ultimate list of picture books about food chains and food webs. Here is my challenge to you. Incorporate more picture books into your middle school science lessons. You’d be surprised at the engagement you get when you pull out a picture book instead of a text book.

Looking for a free Food Chains and Food Web activity for your science class? Check out this silly story!

food-web-activity-silly-story
Life Science, Reading & Writing in Science