Monday, April 13, 2015

Nature vs. Nurture - 7th graders visit CSU

Today I hosted 22 7th graders from Mapleton Expeditionary School of the Arts (MESA) in Thornton, CO (over an hour from here).  Their teacher, Ashley Luythe, asked those of us in the biology department if we could help her teach a unit on heredity and genetics.  I thought the guppy work was perfect since much of our work uses common-garden style experiments to test whether phenotypes are driven by genetic or environmental influences.  So I helped them arrange a trip up to CSU to learn about what we do.

We started the day by talking about genotypes and phenotypes, environmental and genetic influences (with an example using handedness), and why we use guppies to address our questions.  Then we had a lot of fun modeling the effects of color on predation risk using skittles as our prey.  We put them on colored backgroundsto see how many of which colors were "captured".  Once the students generated histograms of their data, we found out that the skittles that matched the background were "captured" less often!

Preparing to "capture" skittles

Making histograms

Discussing the role of color in survival

We also looked at 4 guppies and compared their color.  Two guppies were low predation brothers that were raised in two environments, and the other two were high predation brothers raised in two environments.  By knowing the genetic background as well as the rearing history, we determined that color brightness in guppies was primarily determined by environmental changes!  The students also had a chance to tour our guppy rearing facility at the end of their visit.

Examining guppy coloration

Comparing guppies raised in different environments

Discussing genetic and environmental influences

After talking about guppies, they also heard from Molly Womack, who talked about her research on earless toads!  She brought cleared and stained toads, a fish embedded for histological sectioning, and live eared and earless toads for everyone to see!  She also gave the students a chance to ask those burning questions about her life as a graduate student.  They had great questions!

Examining two species of toads

This looks like a fishing story..."it was THIS big!"

A cleared and stained toad

Thanks to several graduate and undergraduate students for helping with this activity: Rachel Bockrath, Dale Broder, Francis Commercon, Travis Klee, Mitchell Leroy, and Molly Womack!  Hopefully their trip to CSU inspired the 7th graders to learn more about genetics and heredity.

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