Invertebrates are creatures which do not have any form of backbone, the most common of which are the millions of species of insect which exist. However within the overall classification of invertebrates there are a number of lesser known creatures some of which are listed below.
- Sponges. Mainly an ocean dwelling invertebrate animal but occasionally found in fresh water environments. It has a porous skeleton composed of spongin, calcium carbonate, and silica. They often live in large colonies, and in terms of taxonomy occupy the Phylum Porifera.
They take in nutrition by trapping pieces of food from the sea in their body tissue since they do not posses any form of stomach or mouth.