Think about invertebrates for a minute. Do arthropods come to mind? The phylum Arthropoda is the most diverse of the invertebrates, spanning from horseshoe crabs to lobsters to insects. These organisms have in common their exoskeletons, segmented bodies, and jointed limbs. This lesson takes advantage of the phylum’s diversity to spark students’ creativity and problem-solving skills during a review and application activity in which students build their own arthropods and predict the traits of their imaginary offspring.