Have students begin a unit on heredity by discussing family resemblance. Then show them this animated video about Gregor Mendel and his work on traits that were either dominant or recessive.
Let students get hands-on with DNA by creating creatures in DNA Play. This will give them a chance to practice some of the vocabulary they need for their genetics lesson, like genotype and phenotype.
Toothpick Chromosomes
If you ask students what distinguishes a daisy, a fish, a person, and even themselves from a snail or tree, they’ll most likely say that all living things are made of cells. But a person’s uniqueness is due to DNA, the genetic code stored in chromosomes, a group of genes found in every cell.
This free STEM lesson introduces the double helix structure of DNA, the chemical base pairs that make up DNA molecules, and how traits are inherited in the offspring of two parents.
Students also learn what it means for a trait to be recessive or dominant and how alleles, genotypes, and phenotypes work together.
While learning about DNA can be difficult to understand without the aid of a lab, you can help your students visualize it by having them construct toothpick chromosomes.
The lesson is simple to set up and includes instructions for how to use toothpicks to create chromosomes of different lengths and the number of bases in each strand. Then, students can compare their results with those of their classmates.
Another fun way to learn about DNA is by using candy to model the genetic sequence of an organism.
This free STEM activity from the Wellcome Genome Campus uses gummy bears to represent the four nucleotides in a DNA molecule: adenine (A), guanine (G), thymine (T), and cytosine (C).
Twizzlers or other long, soft candy can be used to make the side of a DNA ladder. In this lesson, students build a DNA sequence of an organism and identify complementary base pairing.
Other fun STEM lessons that teach genetics include the Design Y’er Genes lesson from the Genetic Science Learning Center. Students build a small portion of a strawberry chromosome and then use it to model a natural mutation.
Students also get hands-on experience extracting DNA from various types of fruits and vegetables.
Another free genetics resource is the Punnett Squares activity from Basic Genetics STEM. This lesson allows middle school students to determine which family traits will be passed down by analyzing the combinations of alleles a hypothetical person receives from each parent.
Jelly Bean Traits
Genetics is a difficult topic for many students.
As with any new subject, it helps to spend time before attempting to teach it to familiarize yourself with the content and vocabulary. This is especially important for genetics and heredity, which use a lot of unique terms that may not be used anywhere else in the curriculum.
If you don’t understand the material, your students won’t either.
A DNA chain is a useful way to help students visualize the connection between genes and traits. In this activity, students make a DNA chain using jelly beans and toothpicks and then use it to describe how inherited characteristics are passed down from parent to offspring.
Students can also use this hands-on activity to learn about dominant and recessive alleles.
To begin, have each student select a color of jelly bean to represent two alleles, such as Rr or rrr. Each student then writes down their genotype and phenotype (or “trait”) on a worksheet. Then, they work in pairs and combine their alleles to breed (imaginary) babies.
The offspring babies then have their phenotypes recorded.
The simulated breeding of offspring is a great way to illustrate Mendel’s laws of inheritance. Students can also create their own genetics lab to examine a hypothetical natural disaster that has affected the combination of alleles in a population.
For a more advanced look at genetics, have students compare the genotypes of identical and fraternal twins. They can also use Legos to explore how genes pass down through a family trait exchange.
This lesson is an excellent way to introduce students to gene mutations and how they can cause certain diseases, such as cystic fibrosis. Students use the NCBI gene database to identify a mutation in a particular gene that causes Cystic Fibrosis.
Then they investigate how the mutation affects an individual’s ability to taste phenylthiocarbamide (PTC) on a test strip.
Introducing students to DNA is an important first step in teaching genetics. The DNA Play app by Avokiddo provides a fun, interactive way for students to explore the building blocks of life.
After they have explored DNA Play, students can respond to questions on the worksheet and watch a TED-Ed video about Gregor Mendel’s contributions to the study of heredity.
DNA Strands
A DNA model is a great way for students to understand how different genes can contribute to different traits.
This is especially useful for students who have trouble making connections between concepts that are too abstract to grasp. Using an app like DNA Play can also help students connect their hands-on experience with the DNA model to domain-specific vocabulary related to genetics.
DNA is the blueprint that encodes all of the information that determines a living organism’s characteristics. It is a double helix that consists of two complementary strands. One strand contains the genetic code, while the other carries the amino acids needed to make proteins.
Both strands need to be present in order for replication to occur. This is why Gregor Mendel’s pea plant experiment is so important shows that both parents must contribute a copy of each gene in order for offspring to inherit the trait.
To reinforce this concept, have students watch this short video clip explaining how dominant and recessive genes work. Then, students can apply their understanding by creating a Punnett Square based on a celebrity family or a cartoon character.
Another online activity that uses a familiar setting to teach the basics of genetics is Sponge Bob Genetics (see Online Connections).
For younger students, let them take a closer look at their own DNA by giving each student a set of strips of paper that represent DNA. They then need to decode these pieces of paper to determine what traits their parents will pass down to them.
This activity also teaches students that heritable traits can change over time. It is a fun, interactive activity that can be completed in about 50 minutes and will reinforce heritable traits, dominant and recessive genes, segregation, independent assortment, and crossing over.
A final way to connect students with their own DNA is by having them create a family tree that includes both heritable and learned traits. This is a good activity to use with students from grades K-3.
They can interview their parents and siblings to identify these traits, and then draw a picture of their family’s makeup.
Monster Babies
Genetics and heredity are tough topics for kids to understand. The content is so new and different from other science concepts that they have learned that students need lots of practice with hands-on activities before grasping the material.
It is also important for teachers to learn and refresh their understanding of the content before they try to teach it to their students.
Many free, fun, engaging, and interactive resources are available online that can help teach genetics and heredity. Some of these resources are virtual labs that allow students to simulate real-world experiments.
These simulations are a great way to engage students in learning and are often more exciting than simply reading or watching videos. For example, one popular genetics simulation from Labster is Cytogenetics: Perform a Prenatal Diagnosis.
In this simulation, students help a mother-to-be who is worried about her fetus’ condition. Students use a virtual laboratory to simulate amniocentesis and array comparative genomic hybridization, which are two real-world procedures used to diagnose fetal conditions.
This fun, engaging, and interactive activity helps students understand the concept of dominant and recessive genes. It is a great way for students to understand the importance of Mendel’s work and how genetic inheritance works.
This resource includes the Student Worksheet, Teacher Guide, and video topics.
Another way to explore the concept of genetics is through the use of Punnett squares. This lesson is a fun way to introduce the topic to middle school students and allows them to see how simple Mendelian inheritance works.
Students roll the dice to determine their mother’s four traits and then the father’s four traits. They then place the alleles (the characteristics that a person receives from his or her parents) into each box of the Punnett square. Then they draw the baby based on this information.
This is a great way to reinforce the concept of simple Mendelian inheritance and can even be repeated for each generation.
Another fun way to explore genetics is through the use of the mobile app DNA Play. This app is an excellent way for students to build creatures and watch them evolve through a series of mutations.
In this app, students can move the genes around to change the creature’s characteristics and can even tap on the creature to trigger mutations. This is a great way to get students excited about evolution and genetics while also giving them a chance to show off their creativity.