FOSSIL DETECTIVES: AN INTERACTIVE LESSON PLAN ON HORSESHOE CRAB PALEONTOLOGY

A key aspect of geoscience education initiatives is creating engaging programs that inspire future generations to care about the past, present, and future of our planet. Here, we present a lesson plan designed for 6^th -12^th grade students that uses horseshoe crab (Xiphosura) paleobiology as a tool to teach students about paleoecology, phylogenetics, and the scientific process.

Framed as a criminal investigation, students are placed in groups and briefed as “fossil detectives”, who are tasked with identifying horseshoe crabs and determining their evolutionary and ecological affinities. Students are provided with a guidebook, evidence bags, and a phylogenetic poster with missing blanks for five horseshoe crabs, ranging in age from Ordovician to modern. Students use the fossil evidence bags of associated biota and guidebooks to determine the locality, age, identity, and paleoenvironmental affinity of each xiphosuran suspect. With this newfound data, paired with morphological observations, students then place each of the five horseshoe crab suspects within a time-scaled phylogeny poster. Afterwards, students are prompted to use logical reasoning skills to determine the minimum number of times horseshoe crabs have explored non-marine environments and which common ancestors likely made this transition on the phylogenetic tree. A pre- and post-test are also being developed to measure the outcomes of this lesson plan.