Sponges are scientifically classified in the phylum Porifera, composed of four distinct classes: Demospongiae, Hexactinellida, Calcarea, and Homoscleromorpha.

Sponges are fascinating invertebrates with incredible filtering power and dense and porous body structures that are greatly adaptive to their aquatic habitats. There are two basic types of sponges—encrusting and free-standing. The encrusting sponges are known to cover the rock's surface, similar to how moss covers a rock on land, while free-standing sponges have more volume inside compared to their exterior surface area.

Notably, not much is known about the lifespan of sponges, but some massive species found in shallow waters are estimated to live up to thousands of years.

Fun Facts:

• Sponges have strong skeletal structures which help them wade through high volumes of water.
• Sponges eat food by passing water through their bodies through a process called filter-feeding.
• Sponges are inhabitants of coral reef ecosystems, where they are known to affect the quality of water as they filter it, collect bacteria, and process carbon, nitrogen, and phosphorus.
• Sponges are often mistaken for plants. They are one of the simplest multicellular organisms, and due to their appearance and characteristics of the Porifera phylum, they are often mistaken for plants. In addition, sponges are sessile. Like plants, they do not move. Instead, they attach in one place at the bottom of oceans and rivers or on the seabed.
• Unlike most animals, sponges do not have a nervous system or organs. As such, they do not have eyes, ears, or the ability to move or feel anything.
• Sea sponges are often eaten by sea fish, hawksbill sea turtles, and nudibranchs
• According to a study published in the journal Science, humans and sponges had a common ancestor more than 700 million years ago.