Plants in the Dark (Audrey Benson)

Research Question and Hypothesis

Are the plants' appearances influenced by their genes or their environment?

Standards

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.

HS-LS3-3: Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population.

Experimental Design

One plate of tobacco seeds will be grown in the dark and one plate of tobacco seeds will be grown in the light. After one week, the dark plants will be placed into the light and observed. What parts about the plants change once brought into the light?

Independent variable

Light plants are grown in.

Dependent variables

Color of plants, height of plants.

Series

Study the height and colors of plants (dependent variable) as a function of how much light they are exposed to (independent variable) at various times (series).

Constants and Controls

Constant factors are the petri dishes, growth medium, position of the plates, and number of seeds on a plate. Control plants are grown in the light.

Materials

• Albino Tobacco Seeds

• Petri dishes

• Paper towels

• Water

• Grow lights

Procedures

Take two petri dishes and place a paper towel cut to fit into the bottom. Lightly moisten the paper towel. Place 50 tobacco seeds into each petri dish. Label one dish Light and one dish Dark. Place one petri dish under a grow light and cover the other with foil and place elsewhere in the room. Examine the plants after 5 days, then place both into the light and observe the changes each day.

Sample data and graphs

Student Photos

Student Data

Analysis & Conclusions

The conclusion that students should draw from examining the plants is that both environment and genetics have an effect on the phenotype of the plants. The green to white ratio of these plants is 3:1, so some plants will remain white even though they are brought from the dark into the light.

Photos & Movies

References

Science Activity: Albino Plants