This course is an introduction to the vast world of invertebrate organisms. Three major aspects will be presented for each group of invertebrates: 1) ontogeny and phylogeny will look into evolutionary history, diversity, and relationships among groups, with a strong emphasis on genetics of these organisms: 2) functional morphology will provide an understanding of the role of the myriads of morphological adaptations found among invertebrates: and 3) ecological roles of invertebrates in specific habitats.