What are they?

Phylum Porifera (sponges) are probably not the first thing that comes to mind when thinking about ocean life, but they are among the oldest and most widespread animals in the ocean. Porifera, meaning "pore-bearers," are mostly found in marine environments, inhabiting the deep ocean floor and shallow reefs. 

Despite having no true tissues or organs, they have persisted for over 500 million years, revealing some of the earliest innovations in animals, and continue to shape ecosystems. Unlike most animals, they have unique specialized cells that develop into gametes. They capture food particles through filter feeding and exchange gases, helping maintain water quality and supporting other marine organisms