Invertebrates comprise over 90% of all animal life, and are found in every ecosystem on Earth. To this extent, invertebrates exhibit a diverse array of adaptations to enable functioning in various habitats. In this upper-level biology course, we will explore the cellular basis of these adaptations using a systems-level approach, with topics including nutrition & growth, osmoregulation & excretion, defense & integument, reproduction, immunity, and parasitism.