How do living things pass traits to their offspring?
Misconception V Each parent contributes genetic information for certain characteristics and not others (e.g. a child has his father’s nose and his mother’s eyes).
Learning Targets
Learning Experiences
Learning Targets
Learning Experiences
97 I can use a model to determine potential gametes from parental genotype and develop a Punnett square to predict inheritance outcomes. (11, 11b) 98 I can annotate a Punnett square, identifying maternal and paternal gametes, and use mathematics to explain the predicted outcomes. (11, 11a) 99 I can observe traits in offspring and use knowledge of inheritance patterns and Punnett squares to infer parental genotypes. (11, 11a) 100 I can use probability to predict the likelihood of spe- cific offspring given parent traits and inheritance pattern. (11, 11a)
Physical models of chromosomes are used to illustrate the concepts behind a Punnett square. Specific allele combinations are created to represent two parental genotypes. These are placed along the top and left side of the Punnett square and moved into the various boxes to demonstrate offspring genotypes. With this background, students create Punnett squares from practice scenarios to predict offspring (genotypic and phenotypic) ratios. Multiple classroom activities that provide this type of practice are in the resource list. As students become comfortable with single allele crosses, they are challenged to construct dihybrid or trihybrid crosses to determine genotypic and phenotypic ratios at two and three loci. Similarly, students use trait data from a population of offspring to infer the genetic makeup of the parents. Students can obtain offspring phenotypes through direct observation or from simulated data. The significance of the variation between expected and observed results can be analyzed using standard statistical techniques such as chi-square or T test. Students are challenged to propose a genetic cross to identify an the genotype of an organism that displays a dominant trait (but could be homozygous or heterozygous for the dominant allele). Students share their proposed method with classmates and compare their suggestion to standard “test crosses.”
95 I can use models, dia- grams, and/or text to connect Mendel’s laws of inheritance to the biological processes of meiosis. (11, 11b) 96 I can distinguish between homozygous and heterozygous allele pairs and relate these to phenotype. (11, 11b)
Students are first assessed for prior knowledge and misconceptions related to Mendelian inheritance patterns (see resource list for knowledge probes). Students use various print and online resources to review Mendel’s laws of segregation and independent assortment. To connect these laws to the process of meiosis, students return to the physical models of chromosomes used for learning targets #83-90. Models may
need to be modified in order to illustrate different alleles present at a given locus. Students differentiate between homozygous and heterozygous allele pairings and explain the relationship between the inherited genotype and the visible trait phenotype. Chromosome models are manipulated to physically demonstrate the points in meiosis where Mendel’s laws of segregation and independent assortment are observed.
Teacher Tip In this learning progression, it is assumed that students mastered meiosis content. If not, review and scaffolding instruction may be needed.
Teacher Resources
Probe Strategy Option List 10: Number paper 1-10. Students list 10 facts about genetics they “know” prior to any instruction. Listed facts often reveal misconceptions.
Teacher Resources
Teacher Tip Both corn labs involve use of dihybrid crosses whereas the stickleback activity uses monohybrid crosses. Teachers select the activity that is best suited to their student’s ability. While there are not set learning targets for probability, it is a critical concept that cannot be overlooked in a biology classroom. Students may need additional scaffolding and practice with the mathematics behind probability calculations. Possible learning targets could include, “I can investigate probability by collecting and analyzing data from a variety of experiments.”
Uncovering Student Ideas in Life Sciences — by Page Keeley, available for purchase from NSTA press
ChromoSocks are used in previous instruction on chromosome movement during mitosis and meiosis. Using them again to scaffold Punnett square instruction grounds students in the biology and anchors their con- cept of “where the letters outside the box” come from. ChromoSocks — HudsonAlpha Institute for Biotechnology Kit uses socks as model chromosomes to model the movement of chromosomes during cell division. This kit, developed at HudsonAlpha, is available for purchase from Carolina Biology, from ASIM as C4 Chromo, and was distributed at GREAT: Cell Division workshops in 2015/16. Corn Lab — Alabama Science in Motion D7Corn Students compare expected outcomes to actual out- comes of a dihybrid cross. bit.ly/AMSTI-ASIM Amazing Maize — NMSI Laying the Foundation Lesson Students compare expected outcomes to actual outcomes of a dihybrid cross. Includes chi square calculation. Add prelab to Amazing Maize activity to emphasize the significance of the role of Mendel’s laws discussed in the introduction section of this activity.
GeneScreen App — Cold Spring Harbor The app includes four animations introducing the concepts of genetics and inheritance, population genetics, recessive genetic diseases, and genetic screening. bit.ly/CSH-genescreen ChromoSocks — HudsonAlpha Institute for Biotechnology Kit uses socks as model chromosomes to model the movement of chromosomes during cell division. This kit, developed at HudsonAlpha, is available for purchase from Carolina Biology, from ASIM as C4 Chromo, and was distributed at GREAT: Cell Division workshops in 2015/16. Dragon Genetics — Alabama Science in Motion P1DraGen Working in small groups, students determine the genotypes and phenotypes for two generations of dragons. Students employ Punnett squares and become familiar with vocabulary. Examples of complete dominance, incomplete dominance, and sex-linked traits are shown. Mendel’s laws are also illustrated. bit.ly/AMSTI-ASIM
Stickleback Evolution Howard Hughes Medical Institute Students analyze results of genetic crosses
between stickleback fish with different traits. The activity provides opportunities for students to use chi square calculations and experience with a test cross. bit.ly/stickleback-evolution
Dragon Genetics Alabama Science in Motion P1DraGen
Working in small groups, students determine the gen- otypes and phenotypes for two generations of dragons. Students employ Punnett squares and use appropriate vocabulary. Examples of complete dominance, incom- plete dominance, and sex-linked traits are shown. bit.ly/AMSTI-ASIM
Notes:_ _________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
63
A Field Guide to the Alabama Standards
62
The Biology Compendium
Made with FlippingBook - Online magazine maker