Mass Extinctions — And Then What?

It is a good story. Dinosaurs roamed the earth, an asteroid hit, the age of dinosaurs ended. But that’s not the end of the story.

Mass extinction is a phenomenon that intrigues and alarms. Students are drawn to the idea like they would be to any good horror story. It is a problematic story, though, as we make comparisons between the planetary conditions that led to the dinosaurs’ extinction and the changing planetary conditions of the Anthropocene. Where will our changes lead? Is there hope?

In my classroom, the story starts with EarthViewer and its accompanying resources. I ask students to spend time scrolling back in time in the EarthViewer app, exploring the changes that they see in Earth’s atmosphere and on the land. Students are fascinated by tectonic plate movement and changes in day length, both of which they can explore in the app. I ask students to generate a list of questions on a whiteboard, share questions in a group, narrow down their collection of questions to three “great” questions, and then post them in the classroom (real or virtual). The “Student Worksheet - Mass Extinctions” download found on the EarthViewer webpage is a great way to get students to then focus on finding patterns in changes they see through time and link those patterns to mass extinction events. At this point, students begin to see where we are going with this and start to question the current rate of atmospheric change and global extinction. Students are fully invested in finding some answers now.

So what happened to the dinosaurs? This next part of our story is told in The Day the Mesozoic Died, an engaging, fact-filled video that chronicles the events that led to the mass extinction at the end of the Mesozoic and explains the science behind the story. It isn’t just a story of destruction; it is a mystery and the tale of how scientists solved it. Students are provided with an experience that lets them observe scientists at work solving that mystery. The K-T boundary is explained, and the cryptic clues leading to the location of the asteroid impact are unraveled. Even better, though, is that students are prepared to solve the mystery of finding the crater caused by the asteroid in the classroom and are held accountable for what they are learning through resources, such as the activity that accompanies the film, that stimulate discussion and analysis and are closely matched to the event introduced in the film.

To get students to engage in analysis and problem solving, have them find the crater described in the film themselves. In my classroom, solving the mystery of the crater’s location is the best part. To find the crater, students must learn about the events that follow an asteroid impact. This is outlined for them (and the teacher) in a presentation included in the Finding the Crater resources, which also provide an activity, a mystery, and some problem-solving opportunities. The presentation really breaks down what is thrown into the atmosphere after an enormous impact event; how far the pieces of earth, asteroid, and space dust travel; and how these clues can be used millions of years after the impact to determine exactly where the impact occurred. Students use the information from the presentation and the first part of the video and visit 10 K-T boundary sites, which can be downloaded as a PDF from the “Finding the Crater” webpage. These sites are information stations that I’ve posted around the room or school before the activity begins. I printed my set in color and laminated them for future use.

Using the information at each station, students mark the location of the K-T boundary site and the proximity to the impact on a world map (also found on the “Finding the Crater” webpage) until they’ve got all 10 sites mapped. At that point, they have enough information to solve the mystery and can pinpoint where the asteroid hit the planet.

Students are ready to know the rest of the Mesozoic story now, so it is time to go back to The Day the Mesozoic Died and finish up the video (and accompanying activity, if you like). They are also ready to revisit those initial questions they generated from using EarthViewer that helped direct the story they have explored.

Students’ questions generally include thoughts like “Is this the end of the world?” so I don’t like to just end the lesson here. The last bit of The Day the Mesozoic Died sets the stage for the sequel to the extinction story. The end of the Mesozoic was the beginning of a whole new stage of life on Earth. New niches became available, and mammals evolved to fill them. Extend the lesson and keep the story going by delving into a bit of natural selection by using the Great Transitions: Origin of Birds resources. Check out the video educator tip for these resources to hear more suggestions.

It is important to me that students are engaged and enthusiastic about science. Asking them to question leads them to more ownership of their learning. Letting them frame their lessons through inquiry lets me learn how they think and what is important to them. The next generation of scientists won’t be students who learned science through memorization but students who have learned a process of solving problems. My mass extinction lessons start with student inquiry and continue by modeling how scientists solve problems. My experience has been that once students feel powerful enough and fearless enough in the classroom to ask the questions they value, a mindset of problem solving is fostered and new inquiries in the classroom are pursued with enthusiasm and focus. My hope is that that enthusiasm will help them tackle the scientific problems of their generation.