Breeding Critters (Peter Sadorian)
Title: Breeding Critters - Traits
Principle(s) Investigated: Students model the diversity of offspring possible from two parents and discover patterns of inheritance other than strict dominant/recessive traits.
Standards : MS-LS1-5: Construct A Scientific Explanation Based On Evidence For How Environmental And Genetic Factors Influence The Growth Of Organisms. LS.1.B: Growth And Development Of Organisms, LS3.A: Inheritance of Traits, LS3.B: Variation of Traits, Science and Engineering Practices: Asking Questions And Defining Problems, Planning And Carrying Out Investigations, Developing And Using Models, Analyzing And Interpreting Data, Using Mathematics And Computational Thinking, Engaging In Argument From Evidence, Obtaining, Evaluating And Communicating Information. Crosscutting concepts: Patterns, Cause and Effect. MP.4 Model With Mathematics.
Materials: 9 plastic cups, 56 1 1/2 inch foam balls (for critter body segments), 16 1-inch foam balls (for critter heads), 16 blue pipe cleaners, 16 orange pipe cleaners, 100 round head brass fasteners, 40 red straws, 50 green straws, 60 blue straws, 50 yellow paper clips, 40 blue thumbtacks, 100 toothpicks, 67 Critter Breeding Worksheet, 100 Pennies
Procedure: Introduce the investigation of critter traits to learn about variations in the pattern of inheritance discovered by Mendel. Students conduct the critter-breeding simulation and build the offspring critters.Students observe one another's results and answer the Analysis questions.
Student prior knowledge: Genes contain hereditary information. Sexual reproduction involves the union of two sex cells and produces unique individuals that show a combinations of traits inherited from both parents. DNA is the molecule in the genes that carries the hereditary information. Mutations are the results of random errors that occur when DNA is copied before cell division.
Explanation:
Questions & Answers: 1. Which characteristics show a simple dominant/recessive pattern like tail color? 2. For which characteristic do some offspring have traits in between Skye and Poppy's traits? 3. For which characteristic do some offspring have both Skye and Poppy's traits?
Applications to Everyday Life: Alleles apply to all animals who reproduce sexually.
Photographs: Photos and videos on iPad if time permits.
Procedure:
Work in pairs.
Grab 1 worksheet per pair and 2 pennies per group
Place student sheet 65.1 "Critter breeding Worksheet" between you and your partner. The person on the left side will toss a penny for Ocean, while the person on the right will toss a penny for Lucy.
For each toss, each partner should:
- Hold a penny in cupped hands
- Shake it to the count of ten
- Allow it to drop from a height of 20-40cm (8-16 inches) onto the desk.
The partner on the left tosses a penny to determine which allele for number of body segment Ocean gives to his offspring and vise versa for Lucy.
Use the critter code Table 2 below to record the correct alleles under "offspring's trait" on your worksheet.
Continue tossing and filling in Student Sheet 65.1 until you have completed the table.
Find out if your critter is male or female by determining its sex chromosomes as follows:
Ocean is an XY male. The partner representing Ocean tosses a penny. If it shows heads, Ocean donates an X chromosome to the offspring. If the penny shows tails, Ocean donates a Y chromosome to the offspring.
Lucy is an XX female. The partner representing Lucy does not need to toss a penny. Lucy can donate only an X chromosome to the offspring.
After you finish worksheet, use the following materials referenced by Table 1 provided by your teacher to make your critter:
Table 1: Critter parts
Table 2: Critter Code
Analysis Questions:
- What does your critter look like?
- Which characteristics show a simple dominant/recessive pattern like tail color?
- For which characteristic do some offspring have traits in between Skye and Poppy's traits?
- For which characteristic do some offspring have both Skye and Poppy's traits?