1. Genetics and Environmental Influences
Katherine M. Hartman, M.Ed., and Erin S. Kelleher, Ph.D.
University of Houston
Dissemination of this activity provided by Baylor College of Medicine.
Drosophila melanogaster (fruit fly) © Roblan.
GENETICS AND ENVIRONMENTAL INFLUENCES
Overview
Students will test two alternative hypotheses to explain observable differences fruit fly eye color: 1) Eye color differences are caused by environmental differences in diet. 2) Eye color differences are caused by genetic differences. To this end, the student will allow the offspring of fruit flies (Drosophila melanogaster) with different eye colors to develop on different colors of food, and observe the eye color at the adult stage. The following science concepts are addressed in this activity.
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Image Reference
Photo © Roblan. Licensed for use.
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.

2. Observable Traits
What are some of the observable traits of these organisms?
What traits do all the members of the populations have in common? Different?
Which traits are inherited or influenced from their environment?
Flamingos
OBSERVABLE TRAITS
PROCEDURE
Class Period 1: Discussion and Observing Fruit Flies
Project Slide 2. Ask students to make observations of the images. Guide them with information about the organisms. Ask, What are some of the observable traits? What traits do all the members of the populations have in common? Different? Where traits are inherited vs. influenced from the environment? Solicit hypotheses from the students, then discuss each proposed factor together as a group.
Lead students in a discussion of how different factors: environmental (diet, UV light, temperature; students may have other ideas) developmental (age) and genetics all contribute to variation in observable characteristics as you work through the remaining slides.
(continued)
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Image References
Photos courtesy of Pixabay, CC-BY
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.
People

3. Environmental Effects: Diet
Flamingos
Wild caught tuna
ENVIRONMENTAL EFFECTS: DIET
Explain to your students that diet is known to influence pigmentation. For example, flamingos and tuna eat a diet that is rich in pigmented foods, which causes their feathers and flesh to be bright pink.
(continued)
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Image References
Photos courtesy of Pixabay, CC-BY
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.
Shrimp
Farm-raised tuna

4. Environmental Effects: UV Light
Discuss with your students how UV light alters traits, for example by darkening skin color and lightening hair color.
(continued)
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Image Reference
Photo courtesy of Pixabay, CC-BY
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.
How might UV light alter traits? Shown above is skin that has been darkened by the sun. What other traits might be altered by UV light?

5. Age Effects: Environmental or Genetic?
Discuss with your students how aging affects physical traits. What sorts of traits in family members have changed with age? Height, weight, freckles, hair turning gray, and eye color. These are traits that change with age. Are the changes environmental or genetic?
(continued)
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Image References
Photos courtesy of Pixabay, CC-BY
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.

6. Environmental Effects: Temperature
Describe to your students how temperature can affect traits. For example, Siamese cats raised in cooler climates (left photo) exhibit darker pigmentation than those raised in warmer climates (right photo).
(continued)
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Image References
Photos courtesy of Pixabay, CC-BY
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.
Siamese cat raised in a cool climate.
Siamese cat raised in a warm climate.
Which traits changed because of temperature?

7. What About Genetics? Number of fingers Hairline Eye color
Explain to students that variation in genes are known to influence many observable characteristics in humans, such as hairline (straight or peaked), eye color, hairline and the number of fingers and toes. Ask if they’ve noticed unusual traits that run in their families.
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Image References
Photo of Afro North-American female with preaxial polydactyly courtesy of Cplbeaudoin, Wikipedia, CC-SA
Photo of Gary Cooper (widow’s peak) is in the Public domain.
Remaining photos courtesy of Pixabay, CC-BY
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.
Eye color

8. Fruit Flies (Drosophila melanogaster)
What are some of the observable traits?
What traits do all the members of the population have in common? Which are different?
Which traits are inherited or influenced from the environment?
FRUIT FLIES (DROSOPHILA MELANOGASTER)
PROCEDURE (continued)
Project the image of fruit flies with different traits on the front board. Lead students in a discussion by asking questions like those on the slide. [Image: Eye colors (clockwise) are brown, cinnabar, sepia, vermilion, white, wild. Also, the wild red-eyed fly has a yellow body, the sepia-eyed fly has an ebony body, and the brown-eyed fly has a black body.]
Optional: Before continuing with the lab portion of this lesson, you may wish to discuss laboratory safety considerations. The following slide may assist you. Otherwise, proceed to the lab portion of this lesson.
Reference
Hartman K., and Kelleher, E. (2018). Genetics and Environmental Influences on Physical Traits. University of Houston. BioEd Online:
Images Reference
Photo of fruit flies is in the Public domain.
Key Words
lesson, genetic, life science, science, experiment, gene, chromosome, trait, mutation, heredity, offspring, Drosophila melanogaster, fruit fly, fruit-fly, fruit flies, environment, population, middle school, teacher, student,
This activity was funded by NSF Grant to Erin S. Kelleher © University of Houston. Dissemination provided by Baylor College of Medicine via its BioEd Online Website.

9. Science Safety Considerations
Follow all instructions.
Begin investigation only when instructed.
Report accidents.
Do not eat or drink during the experiment.
Wash hands thoroughly after the investigation.
Science Safety Considerations
Students always must think about safety when conducting science investigations. This slide may be used to review safety with your class prior to beginning the activity.
Safety first!
• Always school district and school science laboratory safety guidelines.
• Have a clear understanding of the investigation in advance. Practice any investigation with which you are not familiar before conducting it with the class.
• Make sure appropriate safety equipment, such as safety goggles, is available.
• Continually monitor the area where the investigation is being conducted.
References
Dean R., M. Dean, and L. Motz. (2003). Safety in the Elementary Science Classroom. National Science Teachers Association.
Moreno N., and B. Tharp (2011). The Science of Food Teacher’s Guide. Fourth edition. Baylor College of Medicine.
Key Words
science, classroom, safety, lab, laboratory, rules, safety signs,
© Baylor College of Medicine. 9