Although the FOSSIL project primarily had an out-of-school (“lifelong learning”) focus, we also had many K-12 teachers participate in this program (e.g., Pirlo et al., 2017). Thus, thirty-three (33) lesson plans were uploaded on myfossil.org, originally between 2015-2019. Of those, two core lessons are included below, along with other relevant units that resulted from the FOSSIL and related projects (e.g., SharkAI, NSF 2147625).