Weighing the Evidence for a Mass Extinction: On Land

Topic

Resource Type

Level

Saved By

13 Users

Description

This activity supports concepts covered in the short film The Day the Mesozoic Died. Students analyze graphs and data on pollen grains and fern spores to form a picture of the living landscape before and after the mass extinction that marked the end of the age of the dinosaurs.

Pollen is produced by both gymnosperms and angiosperms. Ferns, on the other hand, reproduce by spores. By analyzing samples of fossil pollen and spores, scientists have found striking differences in the kinds of plants that were present in the upper Cretaceous and the lower Paleogene (formerly referred to as Tertiary periods) — in other words, before and after the K-Pg (or K-T) mass extinction.

In this activity, students first analyze graphs that show the abundance of pollen and fern spore fossils isolated above and below the K-T boundary at a site in New Zealand. They then examine a figure that shows leaf fossils found in rock layers from the Raton Basin formation of Colorado and New Mexico.

A related activity, “Weighing the Evidence for a Mass Extinction: In the Ocean,” provides data on fossils of foraminifera, microorganisms that are abundant in the ocean.

Student Learning Targets

Provide evidence to support the claim that the K-T boundary marks a mass extinction event.
Analyze information contained in various types of graphs and figures.
Draw a representative geological landscape that places data in context.

Estimated Time

One 50-minute class period.

Key Terms

angiosperm, Cretaceous Period, dinosaur, fossil, geologic time scale, Paleogene Period, plant, succession, Tertiary Period

Primary Literature

Vajda, V., J. Ian Raine, and Christopher J. Hollis. “Indication of Global Deforestation at the Cretaceous-Tertiary Boundary by New Zealand Fern Spike.” Science 294, 5547 (2001): 1700–1702. https://doi.org/10.1126/science.1064706.

To access this article, set up a free AAAS account.