|  Invertebrates are a group of animals that have no backbone  Over 95% of all animals on the earth are invertebrates of one form or another  Invertebrates are found just about everywhere in both terrestrial and aquatic habitats  Over 80% of all invertebrates are grouped into the single phylum Arthropoda that includes spiders, crustaceans, centipedes, millipedes and insects  Insects are a group of invertebrates and are the largest Class of organisms in the world  Insects accounting for over 75% of all animal species   |