National Agricultural Literacy Curriculum Matrix
A Recipe for Genetics: Selective Breeding and Transgenics
6 - 8
Students will identify technologies that have changed the way humans affect the inheritance of desired traits in organisms; compare and contrast selective breeding methods to genetic engineering techniques; and analyze data to determine the best solution for cultivating selected desired traits in organisms.
- Then and Now PowerPoint
- Recipe cards (1 recipe per group)
- A Recipe for DNA image
- Natural Selection vs Artificial Selection video
- Selective Breeding station cards (1-2 sets)
- Selective Breeding handout (1 per student)
- GMO Issues cards (1 set per group of 4 students)
- GMO Solutions cards (1 set per group of 4 students)
- GMO Results cards (1 set per group of 4 students)
Concept Elaboration and Evaluation
- Venn Diagram Prompts
Essential Files (maps, charts, pictures, or documents)
- Venn Diagram Prompts
- Selective Breeding Handout
- Selective Breeding Station Cards
- Recipe Cards
- GMO Solution Cards
- GMO Results Cards
- GMO Issue Cards
- Then and Now PowerPoint
- A Recipe for DNA
agriculture: the science or occupation of cultivating the soil, producing crops, and raising livestock
animal husbandry: the science of breeding and caring for farm animals
artificial selection: the intentional breeding of plants and animals to produce specific, desirable traits
domestication: to breed and select animals and plants so they are adapted to living with human beings and serving their purposes
gene: a section of DNA that contains the encoded instructions for making proteins
genetically engineered (GE): process of directly modifying an organism’s genes using biotechnology to produce desired traits
genetically modified organism (GMO): an organism or crop that contains genetic material that has been artificially altered so as to produce a desired characteristic
selective breeding: a process by which humans use animal or plant breeding to selectively develop particular traits in an offspring; also known as artificial selection
transgenic: containing a gene that has been transferred from one organism to another and acts as a synonym for genetically modified
Did you know? (Ag Facts)
- Even though the process of artificial selection had been in use for centuries to create livestock and crops with desirable characteristics, Charles Darwin is credited with coining the term "artificial selection" in his book that he wrote upon returning from the Galapagos Islands.15
- There is no substantiated evidence of a difference in risk to human health between current commercially available genetically modified (GM) crops and conventionally bred crops.5
- Genetically modified (GM) crops in the United States are regulated by the Environmental Protection Agency (EPA), the Food and Drug Administration (FDA), and the United States Department of Agriculture (USDA).6
Background Agricultural Connections
Interest Approach – Engagement
- Begin by asking students to think about the food they eat.
- Has our food always looked the same?
- How has food changed over the years?
- Why has food changed?
- Project the Then and Now PowerPoint on the board.
- Show slides 2-9 to the students. Allow students to look at the ancient/wild varieties of food and guess what it is. (e.g. wild banana, wild watermelon, ancient carrot and corn).
- When students compare the older foods to today’s foods, ask them to point out visible differences including size, shape, color, and the amount of edible flesh. Ask them how they think the taste would compare.
- Project slide 10 on the board and ask students, “What has caused these traits to change?” Lead students to use their existing knowledge to explain what they can about how humans have influenced the look and taste of bananas, carrots, corn, and watermelon? (Through selective breeding.)
- Project slide 11 on the board. Ask students to think about animal traits. Have humans influenced animal traits and genetics? (Yes, by selecting plants and animals with desired traits and breeding those animals to produce offspring with the desired traits.)
- Explain to students that they will discover two methods used by agriculturists and scientists to improve the genetics and traits of the food we eat.
Activity 1: A Recipe for DNA
- Divide the class into six groups.
- Pass out a recipe card to each group.
- Note: The class can also be divided into smaller groups and two copies of each recipe can be distributed if smaller groups would be more ideal for your class.
- Instruct students to read through the ingredients and baking instructions on their recipe card. Ask, "If you were to follow the instructions on your recipe, what product will you end up with?" (Each recipe is for a type of cookie.)
- Allow each group to share their recipe guesses with the class.
- Show students the type of cookie each of their recipes make using the Cookie Key image.
- Ask students:
- Why would each of you end up with a different cookie?” (While each recipe has some similar ingredients, it also includes different ingredients and instructions for mixing and baking resulting in a different type of cookie.)
- Are there any improvements that could be made to your recipes? (Yes, depending on what kind of cookie you want.)
- Could you alter your recipes? (Yes, ingredients could be substituted with other baking alternatives, ingredients could be taken out due to food allergies or intolerance, or ingredients could be added to obtain a desired outcome of some sort.)
- Now ask the students to think about their cookie recipes and relate it to what they know about DNA. Ask:
- What is DNA?
- How can the DNA in living organisms relate to a cookie recipe? (DNA contains “ingredients” and a set of instructions for living organisms. DNA determines the genetic material and outcome of each living organism.)
- Can we improve or alter the DNA of plants and animals? (Yes, through selective breeding and genetic engineering.)
- Show students the image A Recipe for DNA and explain that our DNA is made of different “ingredients” including a sugar phosphate backbone, nitrogenous bases, and hydrogen bonds. Explain to students that adenine (A) always pairs with thymine (T) and cytosine (C) always pairs with guanine (G). The order in which these nitrogenous bases line up acts as a set of instructions for DNA that determines the characteristics and traits in all living organisms.
- Explain to students that our basic knowledge of DNA and genetic inheritance has allowed humans to influence the genetic traits of plants and animals.
Activity 2: Selective Breeding
- Show the video, Natural Selection vs Artificial Selection.
- Following the video, make a Venn Diagram with students to identify the similarities and differences between natural selection and artificial selection (also known as selective breeding). If helpful, display the Natural Selection vs Artificial Selection Venn Diagram.
- Tip: Be sure students recognize that the terms artificial selection and selective breeding are synonymous.
- Set up four different stations around the classroom using the Selective Breeding Station cards.
- Divide the class into four groups and assign each group a specific station around the classroom.
- Note: A second set of station cards can be printed so students are in smaller groups.
- Pass out one Selective Breeding handout to each student.
- Explain to students that they will be rotating through 4 stations. They will have approximately 5 minutes at each station to read the station card instructions, background information, and scenario.
- Set a timer. Consider projecting the timer in the classroom to allow students to gauge their time at each station. Adjust the time limit as necessary. After time is up, groups should rotate to the next station until all four stations have been visited.
- Bring the class back together to discuss each of the stations.
- Allow students to share their thoughts and answers for each of the stations.
- Which animals did they select for breeding purposes?
- How does selective breeding (artificial selection) benefit livestock producers?
- How do these selective breeding scenarios affect us?
- Discuss each of the following scenarios with students.
- Milk Production
- Which cows did you select and why? (Ideally, students should have selected the cows 6, 5, 2, and 3)
- How does selective breeding in the dairy industry affect us as consumers? (Dairy producers are not only selecting healthy livestock but breeding and improving traits that directly affect our food supply. The milk produced on dairies is used to make many products including cheese, yogurt, butter, sour cream, and ice cream.)
- Butterfat Content
- Which Jersey cows did students select to maintain a high butterfat content in the herd? (Ideally, students should have selected the cows 1, 4, 3, and 2)
- Birthweight and Weaning Weight
- Which Angus bull has a low birthweight for small cows, but high weaning weight? Will some students sacrifice a low birthweight to have a very high weaning weight? Remind students that when beef producers sell the calves in the fall, they are paid by the pound, so high weaning weights mean more money. However, calves born at 90-100 pounds can cause problems at birth for heifers and small cows. Ideally, bull 1 with an 80-pound birthweight will still give producers a large calf at weaning.)
- Horned and Polled Cattle
- Which cows should be selected to ensure no offspring have horns? (Cows 3, 4 and 5. When using a horned bull with a genotype (pp), cows with the genotype (PP) should be selected for breeding. (pp) x (PP) = (Pp) The bull will always pass on a recessive horned gene (p) to his offspring, so if you cross a horned bull (pp) with a heterozygous cow (Pp), there is a chance for horned offspring. Breeding the horned bull (pp) with the horned cow (pp) will give producers a 100% chance of having horned offspring.
- Milk Production
- Now ask students what other technologies or management practices can affect desired traits in livestock. Explain that proper care and animal husbandry can help maintain desired traits and genetics. Close monitoring of animal health, proper nutrition, shelter, and waste management all affect livestock production. A calf may be born with superior genetics, but if it is not taken care of properly or fed correctly, inherited traits may be negatively affected.
- To transition into Activity 3, ask students, “What does it mean if an organism is genetically modified?” Allow students to answer or brainstorm ideas.
Activity 3: GMO Issues, Solutions, and Results
- Divide the class into groups of four students.
- Start by passing out a set of GMO Issues cards to each group.
- Instruct groups to read through each of the cards. Explain that each card describes a challenge.
- Discuss each of the issues as a class. Consider asking students the following questions to lead a class discussion:
- Are you familiar with any of these issues related to the production of our food and fiber?
- What are the negative impacts of these issues? (food waste, malnutrition, inefficient use of natural resources like water and soil nutrients, reduced production of food and fiber that humans need.)
- Who is affected by these issues? (Farmers and consumers, so everyone.)
- Can any of the issues be resolved? (Yes.)
- Ask students to brainstorm possible solutions. Prompt students to think about what they have learned about selective breeding. What limitations would selective breeding present?
- Next, pass out a set of GMO Solutions cards to each group of students.
- Instruct students to read through the solutions and match each of the solutions to an issue.
- Pass out a set of GMO Results cards to each group of students. (This will be their third and final set of cards.)
- Instruct students to match each of the results to the issues and solutions cards. Each match should include one GMO issue, solution, and result.
- Discuss each of the GMO cards. Explain that there are currently 10 genetically modified crops available on the U.S. market.
- For a brief explanation of the process of creating a GMO, watch How Are GMOs Made? The Genetically Modified Hawaiian Papaya Case Study.
- Summarize by explaining that genetically modified organisms (GMOs) are created using a scientific process called transgenesis which refers to the process of transferring a gene from one organism to another with the intent of acquiring a new genetic trait.
Concept Elaboration and Evaluation
- After conducting these activities students should be able to identify similarities and differences between selective breeding and transgenesis. Draw a Venn Diagram on the board labeling one circle "Selective Breeding" and the other circle "Transgenesis."
- Pass out the Venn Diagram Prompts to various students in the class and have them add the strip of paper to the correct portion of the diagram. Discuss and provide clarification as needed.
- Review and summarize the following key concepts with your students:
- DNA makes up the instructions for all living things.
- Humans can influence the inheritance of traits by selecting only parents that have desired traits through a process called selective breeding (also known as artificial selection).
- Technology can increase our ability to select and perpetuate helpful genetic traits in the plants and animals that provide our food. Transgenics is one example.
We welcome your feedback! Please take a minute to tell us how to make this lesson better or to give us a few gold stars!
Selective breeding and transgenics are just two breeding techniques. Use the Crop Modification Techniques infographic to introduce more.
Suggested Companion Resources
- Selectively Breeding Sheep: Punnet Square Practice (Activity)
- Crop Modification Techniques (Poster, Map, Infographic)
- Genetically Modified Food: Good, Bad, Ugly (Multimedia)
- How Mendel's Pea Plants Helped Us Understand Genetics (Multimedia)
- Learn GMO (Multimedia)
- Natural GMO? Sweet Potato Genetically Modified 8,000 Years Ago (Multimedia)
- Why are GMOs Bad? (Multimedia)
- GMO Answers (Website)
- Genetic Science Learning Center (Website)
Agricultural Literacy Outcomes
Science, Technology, Engineering & Math
- Describe how biological processes influence and are leveraged in agricultural production and processing (e.g., photosynthesis, fermentation, cell division, heredity/genetics, nitrogen fixation) (T4.6-8.b)
- Describe the process of development from hunting and gathering to farming (T4.6-8.c)
- Discuss how technology has changed over time to help farmers/ranchers provide more food to more people (T4.6-8.d)
- Provide examples of science and technology used in agricultural systems (e.g., GPS, artificial insemination, biotechnology, soil testing, ethanol production, etc.); explain how they meet our basic needs, and detail their social, economic, and environmental impacts (T4.6-8.i)
Education Content Standards
MS-LS4 Biological Evolution: Unity and Diversity
MS-LS4-5Gather and synthesize information about technologies that have changed the way humans influence the inheritance of desired traits in organisms.
Common Core Connections
Reading: Anchor Standards
CCSS.ELA-LITERACY.CCRA.R.1Read closely to determine what the text says explicitly and to make logical inferences from it; cite specific textual evidence when writing or speaking to support conclusions drawn from the text.
CCSS.ELA-LITERACY.CCRA.R.7Integrate and evaluate content presented in diverse media and formats, including visually and quantitatively, as well as in words.
Speaking and Listening: Anchor Standards
CCSS.ELA-LITERACY.CCRA.SL.2Integrate and evaluate information presented in diverse media and formats, including visually, quantitatively, and orally.
CCSS.ELA-LITERACY.CCRA.SL.3Evaluate a speaker’s point of view, reasoning, and use of evidence and rhetoric.