Environmental Influence on Genotypes and Phenotypes

Contributor
Victor Sampson and Sharon Schleigh
Type Category
Instructional Materials
Types
Lesson/Lesson Plan
Note
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.

Reviews

Description

This is one of 30 lessons from the NSTA Press book Scientific Argumentation in Biology. The lesson engages students in an argumentation cycle by posing a question on the influence of the environment (light) on the genotype or phenotype of the tobacco plant. The lesson provides three possible answers to the question and students design and conduct controlled experiments using tobacco seeds to determine the most valid explanation. Students are challenged to collect evidence needed to construct an argument defending their claim of environmental influence on tobacco plants. Students need prior knowledge of Mendelian genetics to construct a valid argument. Students develop a whiteboard presentation to justify their claims and share their work using a round-robin format. Teachers are encouraged to refer to the preface, introduction,  assessment samples, and appendix provided in the full book for important background on the practice of argumentation and resources for classroom implementation. The standards addressed in the lesson are also included in the teacher’s notes.

Intended Audience

Educator and learner
Educational Level
  • Grade 12
  • Grade 11
  • Grade 10
  • Grade 9
Language
English
Access Restrictions

Available for purchase - The right to view, keep, and/or download material upon payment of a one-time fee.

Performance Expectations

HS-LS3-2 Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

Clarification Statement: Emphasis is on using data to support arguments for the way variation occurs.] [Assessment Boundary: Assessment does not include the phases of meiosis or the biochemical mechanism of specific steps in the process.

Assessment Boundary: Assessment does not include the phases of meiosis or the biochemical mechanism of specific steps in the process.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
This collection of lessons was published before the final release of the Next Generation Science Standards. However, the lessons are explicitly aligned to the Disciplinary Core Ideas, Crosscutting Concepts, and Science and Engineering Practices from the Framework for K-12 Science Education. Students need prior knowledge of experimental design or the teacher needs to provide instruction on designing a controlled experiment. Exposing one group of seeds to light and not exposing one group to light should be a part of the experimental design. Students use collected data to develop an argument that supports one of three possible claims about the influence of the environment on the genotypes and phenotypes of an organism. A data collection tool is not included in the lesson. The teacher will need to provide a collection tool or have students create their own tool. Additional evidence of environmental influence can be shown by asking students to expose the plants grown in the dark to light. The plants turn green. Teacher-led questions and discussion help students understand the plants would not have been able to turn green if their genotype changed. The activity is designed for high school students and takes between 100 and 150 minutes to complete. An additional week is needed to allow the seeds to germinate. Suggestions for implementation are included in the teacher’s notes.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Students use mathematical and computational thinking to predict the genotypic and phenotypic ratios of offspring in the F1 generation of tobacco plants. They design a controlled experiment and use observational evidence data to make a claim about which of the three possible explanations is the most valid about the influence of the environment on genotypes and phenotypes of tobacco plants. After deciding on which answer supports their data, student develop a written argument to support their claim and share their argument with their peers. Teachers need to provide instructional time for students to critique each argument. Students use the peer reviews to revise and create a final written argument to support their claim. Teachers should close the lesson with an explicit discussion on the ways that the environment can influence a phenotype.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
To develop a conceptual understanding of the role of the environment on genotypes and phenotypes and write an effective argument, students will need prior knowledge about genes, the law of segregation, and different modes of inheritance. Teachers will need to provide instruction on how to use Punnett squares to predict genotypic and phenotypic ratios and analyze data collected from an experiment. The authors suggest this activity should be used as part of a unit on genetics. It should be used to introduce students to the role of the environment on traits. In this activity the 200 seeds grown by the students should produce offspring with a 1:2:1 genotypic ratio and a 3:1 phenotypic ratio if there is no environmental influence. Phenotype can be influenced by the amount of light or the intensity of light. Plants not exposed to light after they germinate will appear white regardless of the genotype.

Crosscutting Concepts

This resource is explicitly designed to build towards this crosscutting concept.

Comments about Including the Crosscutting Concept
Students use the nature of science, prior knowledge of Mendelian genetics and computational and mathematical skills to design and analyze experimental data that suggest tobacco plants grown in the light display an expected phenotypic ratio but not those grown in the dark. Thus, supporting the claim (cause and effect) that the environment has an influence on the phenotype of these plants. When plants grown in the dark were exposed to light they displayed the expected phenotype. This supports the idea that environment does not affect the expected genotype of these plants. Teachers can extend the lesson with a “nature versus nurture” lesson using an activity from Discovery Education (http://www.discoveryeducation.com/teachers/free-lesson-plans/nature-versus-nurture.cfm).

Resource Quality

  • Alignment to the Dimensions of the NGSS: This lab activity involves students in all three dimensions of the Next Generation Science Standards, as they observe genetics variations in the offspring of two heterozygous tobacco plants, use evidence to make a claim about how the environment influences the phenotypes of the offspring, and develop an explanation to support one of the three answers provided in the activity. This and the other lessons in this book were designed explicitly to address the three dimensions of the Framework for K-12 Education. Teachers are advised to familiarize themselves with Sampson and Scheigh’s argumentation framework, suggested teacher behaviors, and assessment approaches before implementing the lesson.

  • Instructional Supports: Students are engaged in doing science by designing and conducting a controlled experiment. They collect and analyzed data to make sense of the nature versus nurture phenomena. Students use their findings to create and justify an argument on the influence of the environment on genotypes and phenotypes in tobacco plants. This activity supports students in developing a deeper understanding of the principle of dominance, law of segregation, and specific modes of inheritance such as incomplete dominance and codominance. Teachers can extend the lesson by discussing how scientific explanations must be consistent with observational evidence about nature and how mathematics plays an important role in scientific inquiry. The preface, introduction, assessment chapter, and appendix of the full book provide content support information for teachers who wish to use this lesson.

  • Monitoring Student Progress: Constant monitoring and feedback are built in to the Sampson and Schleigh’s argumentation framework, but they rely on skillful teacher interactions with students. Supportive questioning is critical to student success in this and similar lessons. Teachers should monitor and provide feedback to students as they construct initial arguments, present and critique arguments, and draft final written arguments. Teachers can also model and guide students in providing constructive peer feedback. Teachers should also consider allowing students to revise and improve final written arguments based on teacher and peer feedback.

  • Quality of Technological Interactivity: This lesson does not have technology component.