Invertebrates - marine

Of the world’s c. 1.8 million described species, around 97 percent are invertebrates. Invertebrates were the first animals to evolve on earth, and exhibit a staggering level of diversity, from the relatively simple, such as the common jellyfish, to the much more complex arthropods and molluscs, such as the giant octopus. Besides the lack of a backbone, members of this large, informal group do not have bony skeletons or true jaws. Invertebrates are particularly abundant in the world’s oceans, where they are subject to an increasing variety of threats, including pollution, climate change, over-collection, habitat degradation and competition with invasive species.

Explore ARKive for videos and images of endangered invertebrates, and learn about invertebrate conservation, biology and more in our species fact-files.