Part I—Disappearing Marine Iguanas
Liz sat at a table in the student union enjoying a cup of coffee and flipping nonchalantly through her vertebrate biology textbook. She had a paper due in two weeks and still had not decided on a topic. Her instructor focused mainly on taxonomy and anatomy in class, but Liz was more interested in ecology. Her friend Abby, carrying a tray with an enormous cinnamon roll, sat down across the table.
“Still trying to figure out a topic for your paper, Liz? Why not follow up on those antifreeze mechanisms in Antarctic fishes?”
“I thought of that but I don’t want to get into all that cell biology and chemistry. I’m more interested in whole organisms that I can see; like, maybe those marine iguanas in the Galápagos. Dr. Parisi had some pictures of them from a trip she took in 1999. She said that there were a whole lot less of them than she expected, and the guides told her that most of the islands had 40–90% mortality in the previous year.”
“What could have killed the iguanas that fast?” exclaimed Abby as she pulled her laptop out of her backpack. “Just a minute while I Google the Galápagos.” Abby quickly found a map of the Galápagos archipelago.
Questions
- Using the map and the minimal knowledge that Liz has at this point, propose three different hypotheses regarding the sudden high mortality of marine iguanas. Wait for a class discussion before proceeding to the next question.
- After seeing hypotheses from all groups, choose the hypothesis that seems most likely to your group and determine what evidence you would need to support (or refute) it.
Date Posted: 10/22/07.
Image credit: Photo of marine iguanas ©Roman Shiyanov—Fotolia.com.
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