Animal Science: Unit 3 Genetics and Breeding
Lesson: Genotype, Phenotype, Purebred Breeding, and Crossbreeding
Frameworks: 3.4, 3.5
Material List:
Situation:
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Students are studying about the differences between genotype and phenotype; and
purebred breeding and crossbreeding.
Objectives:
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Define genotype and phenotype and know the differences with 100% accuracy.
Define purebred breeding and crossbreeding and know the differences with 100%
accuracy.
Identify examples of genotype and phenotype in animals with 80% accuracy.
Identify purebred and crossbred animals with 80% accuracy.
Key Terms:
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Genotype: Genetic makeup of an animal.
Phenotype: The outward expression of a gene.
Purebred Breeding: The breeding of animals within the same breed.
Crossbreeding: The breeding of two different pure breeds.
Interest Approach:
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Show students pictures of animals that are purebred and crossbred and ask them if they
know the difference. Also ask the students if they know what the genotype and phenotype
of the animals are.
Reasons to Learn:
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Why should we know the difference between genotype and phenotype?
Why should we know the difference between purebred and crossbred animals?
Why should we know how to identify animals that are purebred or crossbred?
Questions to Answer:
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What is the difference between genotype and phenotype?
What is the difference between purebred and crossbred?
What are examples of animals that are purebred and crossbred?
Answers to Questions:
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What is the difference between genotype and phenotype?
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Genotype: Genetic makeup of an animal.
o Genotype is in the gene. It is something that we cannot directly see.
Phenotype: The outward expression of a gene.
o Phenotype is the characteristic of the animal that we can see. Ex, Holsteins are
black and white.
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What is the difference between purebred and crossbred?
o Purebred Breeding: The breeding of animals within the same breed.
 Ex, Angus breeds with Angus not with Red Angus
o Crossbreeding: The breeding of two different pure breeds.
 Ex, Angus can breed with Red Angus
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What are examples of animals that are purebred and crossbred?
o Animals are considered pure bred when they meet all the characteristics of the
breed.
o Owners of the animal will be able to track the lineage of the animal to ensure
heritage.
o Many ranches will have a purebred stud.
 This can bring in a lot of money due to other owners wanting their females
to breed with a purebred.
Activity: (100 points)
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Students have already learned about punnett squares from a previous lesson. After they
learned about phenotype/genotype and purebred/crossbred they will make their breed of
animal.
o Students will get in groups of 2-3 and make up their own breed of animal.
o They can mix whatever breeds they want together, or they can have two of the
same breeds.
o Students will work on this project at the end of class until the bell and then will be
given 5-10 minutes to finish during the next class period where they will then
present their animal to the class.
 Students will discuss the name of the animal and how they came up with
the new breed.
o Students will be graded on: correct use of punnett squares, creativity, and
presentation.
o
Review:
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Ask students the questions to ask and get them to respond to you what they learned.
o What is the difference between genotype and phenotype?
o What is the difference between purebred and crossbred?
o What are examples of animals that are purebred and crossbred?