Marine invertebrates are animals that inhabit the ocean and lack a backbone. They are diverse and play critical ecological roles in marine ecosystems. Synonyms for marine invertebrates include sea creatures, ocean invertebrates, marine fauna, and aquatic invertebrates. They are vital components of the food chain and provide a significant source of protein for human consumption. Some examples of marine invertebrates are sea stars, crabs, jellyfish, squids, and octopuses. These creatures have unique adaptations that allow them to survive in their respective marine environments, whether it is in intertidal zones, coral reefs, or deep-sea habitats. The study of marine invertebrates, called marine invertebrate zoology, is essential for understanding the biodiversity and ecological processes in the ocean.