All About Sponges


The scientific name of a sponge is Porifera, which means pore-bearing.

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Porifera. © 2004 Dlloyd

What are Sponges?

Sponges are the simplest form of multi-cellular animals. They are very diverse and come in a large variety of colours, shapes and structural complexities. They range in heights of 1-200cm and in diameters of 1-150cm. They have partially differentiated tissues, and not true tissues. Sponges don’t have internal organs. They don’t have muscles, a nervous system, or a circulatory system. Their walls are lined with many small pores called ostia that allow water flow into the sponge.   

The structure of a sponge is simple. One end is attached to a solid such as a rock while the other end, called the osculum, is open to the environment. Sponges are able to get microorganisms such as algae and bacteria for food through openings. Some sponges are carnivorous and use their spicules to capture small crustaceans. 

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Structure of a sponge. © spongejk1

What are Sponges Made of?

Sponges are made of four simple and independent cells. The first are the collar cells, which line the canals in the interior of the sponge. Flagella are attached to the ends of the cells and they help pump water through the sponge’s body. By pumping water, they help bring oxygen and nutrients to the sponge while also removing waste and carbon dioxide. The second cells are the porocytes, which are cells that make up the pores of the sponge. Epidermal cells form the skin on the outside of the sponge. Finally, the amoebocytes exist between the epidermal and collar cells in an area called the mesohyl. They carry out functions of the sponge and help transport nutrients. They also form spicules, which are the sponge’s skeletal fibers. They work together with the collar cells to digest the food for the sponge and produce gametes for sexual reproduction.

What are Some Types of Sponge?

There are four different types of sponges from different classes: Calcarea, Hexactinellida, Demospongiae, and Sclerospongiae. They are split into the classes based on the type of spicules they have. For example, spicules may be made of calcium carbonate or a spongin fiber.

Where Do Sponges Live?

Sponges live in all types of regions all over the region. They are able to thrive in most environments. 99% of all sponges live in marine water, but some sponges made of spongin fiber live in freshwater. Sponges can be attached to surfaces anywhere as deep as 8km in the ocean on the bottom of the ocean floor. There are a higher number of sponge individuals and sponge species in the tropics of all regions because the water is warmer. They like to live in clearer waters over murky waters formed by currents. The murky waters may often clog the pores on the sponges so the sponge cannot get its nutrition and oxygen to survive.

What is their Importance to the Ecosystem?

Sponges are important in nutrient cycles in coral reef systems. Scientists believe they may be important factors to changes in water quality, whether good or bad. Scientists analyze how fast sponges breathe and the amount of nitrogen they release while doing so. Sponges collect bacteria when they filter the water around them. These bacteria are believed to be able to do many things. First, these bacteria may be able to create forms of nitrogen from the nitrogen gas in the water that may be nutritional for the sponge. They may also be able to turn ammonium from the sponge’s breathing into nitrogen gas that is then released into the atmosphere. This process would lower excess nitrogen levels in coral reefs, also preventing harmful ecosystem changes. Scientists believe that the conversion of nitrogen gas into useful nitrogen is also beneficial to the survival of other organisms in the area. They are hoping to have discovered a pathway for the removal of excess nitrogen from coral reefs.

What are Some Adaptations They Have to their Environment?

Sponges are strong animals with dense skeletons that are well adapted to their environments. As they may live almost everywhere, they adapt to the regions and surfaces they grow in. Certain sponge species are adapted to freshwater environments. Their skeleton types allow them to live in either hard or soft sediments. Their pores allow them to filter the water around them for food. Inside the sponge, there are flagella that create currents so their collar cells may trap the food. Sponges may have adapted to these feeding habits from a long time ago when food sources may have been scarce. 

Sponges have strong structures that are able to handle the high volume of water that flows through them each day. By constricting certain of their openings, sponges are able to control the amount of water that flows through them. Scientists believe that sponges are colourful because the colours act as a protection from the sun’s harmful UV rays.

Sponges have been around for a very long time.  This is because although the world is constantly changing, sponges are still able to respond to these changes through adapting to their environment. Sponges are also able to release toxic substances into the environment around them to make sure they have a good place to grow in.

How Do Sponges Reproduce?

Sponges may reproduce sexually and asexually. This helps keep them alive in their habitats. Most sponges are both male and female. In sexual reproduction, they may play either role. The ‘male’ sponge would release sperm into the water, which would travel and then enter a ‘female’ sponge. After fertilization in the sponge, a larva is released into the water. It floats around for a few days and then sticks to a solid to begin its growth into an adult sponge. 

Sponges are also able to reproduce asexually through budding. This is when a small piece of sponge is broken off but is still able to survive and grow into another sponge. Sponges are also able to repair damages to their bodies. These characteristics of sponges are ideal because even small parts of sponges may survive in the water. Diversity is created when different sponges reproduce with other different sponges.     

Information on the Internet


1. Campbell, Neil A. and Jane B. Reece. Biology. 6th ed. Toronto: Pearson Education Inc as Benjamin Cummings, 2002. pg 636-637, 647-648.

2. “Sponge”. Columbia Encyclopedia. 6th ed. 2005

3. David, Seonaid. Class Notes - Lab Manual. “SBI3U - Diversity of Living Things”. Pg. 17-19, 30-31

Learning Information

About This Page

Ms. Ianni

Author: spongejk1
Classroom Project: sponge
Havergal College
Toronto, Ontario Canada

License: Tree of Life & Partners uses only - Version 1.0

Correspondence regarding this page should be directed to , Havergal College

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