Unit Overview

Fossils are millions—even billions—of years old. New fossil discoveries can provide cutting-edge evidence about the history of life on Earth. In fact, in addition to fossils of other early species, paleontologists discover about 14 full dinosaur specimens every year.

In the Evolutionary History unit, students will take on the role of student paleontologists investigating a Mystery Fossil, which serves as the anchor phenomenon for the unit. This fossil is based on a real cetacean (whale) fossil excavated in Pakistan in 2000. The students’ task is to determine the Mystery Fossil’s evolutionary history so that they can accurately place the specimen in a museum exhibit. To gain an understanding of how paleontologists determine relationships between species, students use the Evolutionary History Simulation to analyze real fossil evidence and explore relationships on an interactive evolutionary tree. With a fossil collection at their fingertips, students identify similarities and differences among the skeletal structures of both extinct and living species. Students also use the Natural Selection Simulation to revisit principles of natural selection, applying this concept to understanding how one species becomes two. They read several articles about evolution, speciation, and natural selection, and they create models to show their thinking. By the end of the unit, students can use their analysis of skeletal structures to determine where they should place the Mystery Fossil in the museum, according to what type of organism the evidence shows it to be most closely related to—whales or wolves.