Unit Summary At the beginning of this unit, students hear about the surprising fossil of an ancient penguin (nicknamed “Pedro”) in a podcast from the researchers who found and identified the fossil. Students analyze data about modern penguins and Pedro to develop initial explanations for how these penguins could be connected. They brainstorm about 1) Where did all the ancient penguins go? 2) Where did all the different species of modern penguins come from? and 3) What other organisms alive today might also be connected to organisms that lived long ago? After exploring variations in body structures and behaviors in modern penguins and ancient penguins, they also analyze data from ancient and modern species of horses, whales, and horseshoe crabs to see whether these organisms have similar patterns. Then, to figure out the cause of the changes they have observed in populations, students explore more recent cases of changing heritable trait distribution in populations and explain them by developing a model for natural selection. In the last part of the unit, students use their model for natural selection to explain how some body structure variations in different species of modern penguins could result from natural selection and how they could descend from a common ancient ancestor penguin population. They analyze embryological data to their argument supporting how different species may be connected. Finally, students take stock of all the questions they answered in this unit and previous OpenSciEd units and identify questions they look forward to figuring out in high school. Most supplies are included with this kit. Please refer to the link below for instructions and printable materials. https://www.openscied.org/instructional-materials/8-6-natural-selection-common-ancestry/.