What is an invertebrate?

An invertebrate is defined as an animal that lacks a backbone or vertebral column. This classification encompasses a vast range of organisms, including insects, arachnids, mollusks, and crustaceans. Invertebrates make up the majority of animal diversity on Earth, showcasing a wide variety of forms and adaptations that thrive in numerous environments.

In contrast, plants are classified separately and do not fall under the animal kingdom. Chemical compounds refer to substances composed of two or more elements and do not relate to biological classifications, while structures in vertebrates pertain specifically to animals with backbones. Understanding that invertebrates are crucial to ecosystems can illuminate their roles in various biological processes, including pollination, nutrient cycling, and as a food source for vertebrate species.