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Rodents, Frogs & Worms...Oh My!

Porter Swentzell Science Poster


Northern's Sixth Annual Student Research Conference wrapped up spring semester. The poster session showed off students' scientific interests and research skills.

You never know what College students will discover when given an assignment to research a topic of interest to them. At Northern’s Student Research Conference on May 5th, it was easy to see that if given the opportunity and encouragement, students will exercise their intellectual curiosity and produce substantive and engaging research reports.

Reporting on a wide variety of topics within each discipline, all of the students’ posters were both informative and entertaining. And some of them were beautifully designed. It was clear, upon speaking with them, that the student investigators knew their topics and were not afraid to answer questions related to their research.



One of the more intriguing topics centered on a revisit to the famous Clark Doll Study (Clark & Clark, 1939). In the original study, Kenneth and Mamie Clark showed four dolls to a group of children. Participants were asked to  identify which dolls were “nice, mean,” or “bad.” The children identified the lighter-skinned dolls as having positive attributes and preferred to play with them, while the dark-skinned dolls were labeled as “bad” or “mean.”

Ethnic DollsIn an update to the original well-known Clark Doll Test, student researcher Kayla Montoya replicated the Clarks’ methods using black, white, Asian, and Hispanic Dolls. The Northern study participants were Hispanic girls 4-5 years of age. Unfortunately, the results show that the modern-day participants were not any more self-aware or empowered than those in the original experiment.  Montoya found results consistent with the Clark test results. When asked “Which Baby is the Hispanic Baby?” the majority of participants chose either the white or Asian doll. When asked “Which baby looks like you?” all participants chose either the white or Asian doll. When asked “Which baby is the mean baby,” or “Which baby is the bad baby,” four of the six participants chose the black dolls. When asked “Which baby is the nice baby,” all but one chose the white doll, and that one chose the Hispanic doll.



Student researcher Felicia Jimenez is pursuing a Bachelor of Science in Biology with a minor in Chemistry. Her poster clearly illustrated her research comparing behaviors and habits of two distinct species of tree frog. To make the comparison, Jimenez ordered a male and a female Peacock Tree Frog and a pair of Red-eyed Tree Frogs. When asked whether at the end of the study these animals had become pets, she replied yes, and added that she in fact had named them Meredith, Derek, Yang, and Owen.

Both species are nocturnal. The Red-eyed Tree Frog (Agalychnis Callidryas) is native to Central America, while the Peacock Tree Frog (Leptopelis Argentius) is native to Tanzania and the African Savannah.

Their habitats differ: The habitat for Peacock Tree is a 20 gallon aquarium, and they have a habit of burrowing. The habitat for the Red-Eyed Tree Frog is a medium-sized Terrarium. They have suction toes which enable them to do a lot of climbing and clinging. Both species are nocturnal.

Jimenez and her faculty sponsor, Dr. Virginia Salas, explained that activities measured differed in the two species in that they were active at completely opposite times of day and night.
Their defense mechanisms differ as well: Peacock frogs have one set of eyelids and do not cover their eyes when threatened, but the eyes change colors when they perceive a threat. The red-eyed frog exhibits “startle colorization” and turns “completely Technicolor.” This mechanism is used to startle and discourage predators.



Student investigator Tracy Lujan measured the effects of pesticides on earthworms using two pesticides: Sevin-5 and Diazion.

She obtained soil from nearby apple orchards that had been sprayed in the past but to which no pesticide was added recently. Lujan placed earthworms into habitats made of coffee cans filled with this control dirt (no added pesticides). She then used 3 containers, put control mix in each, and placed 3 worms in each can.

Adding Sevin-5 to one container/habitat, Diazion to another, and both chemicals to the third container, Lujan created three pesticide-laced environments for her subjects. The earthworms lived in these habitats for one week, after which they were weighed and tested for mobility and travel distance. Some weight loss was measured in the worms that were exposed to pesticides, as was some mobility loss.

After four weeks in the pesticide-laden soil, the worms suffered a few fatalities and a zero reproduction rate. When asked whether her research results could be connected to the effects of pesticides on humans, Lujan replied in the affirmative.



In a beautifully designed poster, Joshua de Aguero and faculty sponsor Dr. Ulises Ricoy showed the results of methamphetamine dialysis on rodents’ hippocampi. Injecting Ringer’s vehicle (saline solution)  alone, and Ringer’s vehicle to which he had added either methamphetamine or morphine, Dr. Ricoy measured the rodents’ activity using a photobeam.

De Aguero analyzed differences in rodents' activity levels depending on both the delivery location of the solutions and on the mixture and quantity of solutions delivered.The principal discovery was that methamphetamine in Ringer’s vehicle delivered to rodents’ hippocampi resulted in higher levels of measured locomotor activity in the rodents. De Aguero mentioned that one reason for testing the effects of delivery of methamphetamine directly to the hippocampus was because this part of the brain has been linked to addictive tendencies in humans.

There were many equally impressive posters; Northern students proved to be not only exacting researchers, but also—and perhaps more important—effective communicators of research results.


Story by Lisa Powell