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History and Evolution of the Earth

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CATEGORY: Academics
TYPE: Articles
RELATED PROGRAMS: Geology

By | Andrea Wilhelmi ’13 

“The coolest thing I’ve learned is probably that 500 million years ago, Minnesota was an ocean floor,” says Lydia Craig 15.

Most of us learn that Earth’s continents were not always arranged as they are now. But not many think about where they will head next. Macalester professor Raymond Rogers teaches his students in first-year course History and Evolution of the Earth that marine fossils in Alaska came from the tropics and the Baja Peninsula is sliding toward Oregon.  
 
“Before this class I didn't look at rocks at all and just thought they were normal, boring, everyday objects,” says first-year student Naomi Becker (Washington, D.C.). Taking the class, she says, has helped her look at the world in new ways. “A rock I find on the sidewalk could be 3.5 billion years old.”  
 
Geology can reveal trends over the Earth’s lifespan and foster speculation about its future. This includes paleobiogeography, or the use of geological evidence to explore past distributions of life. A field trip to Whitewater State Park in southeastern Minnesota helped students understand how ancient terrestrial features were related to the life forms that inhabited them. “Fossils are not haphazardly scattered,” Rogers told his class, insisting that they tell more than “loving little dinosaur stories.”  
 
Students were encouraged to draw conclusions about ancient ecosystems based on the abundance of different fossils. Becker saw evidence of geologic history in ordinary places. “The coolest thing I've learned is probably that 500 million years ago, Minnesota was an ocean floor. The class found tiny trilobites, fossilized coral, and evidence of burrowing organisms, she says, “in what looked like a pile of dirt and rocks on the side of the highway.” Lydia Craig (Suttons Bay, Mich.) says the trip, which included camping in the park, “was a good opportunity to bond with classmates and connect what we were learning in class to the field.”  
 
Geology 165 is also a residential course, which means that all the students live together on one residence hall floor—in this case the third floor of Turck. “Our hall is really close, and we do a lot of stuff together outside of class,” says Rachel Seidner (San Antonio, Texas). “Having a residential course has definitely helped to foster these relationships.”

Becker likes the ease with which she and her classmates can form study groups, as it can be hard to “keep track of events in the context of overall geological time.” Despite the help of fellow students, says Craig, “Studying for the first test was nerve-wracking.”  
 
What these students learn together is relevant beyond the classroom. They’ll leave the course equipped to enter an urgent discussion about Earth’s evolution. Scientists must gather what information they can before global speciation changes, as it has throughout time. Rogers says that 8 to 9 million species inhabit the planet today. Of these, we’ve named only about 1.4 million. “What’s the race right now?” he asked the class in a lecture. “To name things before they disappear. And they’re disappearing fast.”

PUBLISHED: 06/03/2013