Bibliography

"Sponges." http://www.reef.edu.au/asp_pages/secb.asp?FormNo=147

Michael McDarby. "An Online Introduction to the Biology of Animals and Plants." 2001. <http://faculty.fmcc.suny.edu/mcdarby/Animals&PlantsBook/Animals/02-Sponges&Cnidaria.htm>

"Sponges - Phylum Porifera." 2006. <http://www.geocities.com/sciencejanetc/7th_8th_grade/animal_kingdom/sponges.html>

"Sponges - The Real World." <http://library.thinkquest.org/26502/level2/Process/index-process.htm>

Myers, P. 2001. "Porifera" (On-line), Animal Diversity Web. Accessed February 25, 2007 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Porifera.html.

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Interesting Facts

• Sponges do not have a brain.
• Many years ago, in Roman times, sponges were used as an early form of toliet paper.
• In modern day, sponges are used for everyday cleaning as their pores absorb stains and dirt.
• Factories now create "fake" sponges since it is easier than harvesting them.
• In ancient times, sponges were used to create art in Greece.
• In Egypt, sponges were used for bathing and cleaning.
• When sponges are harvested, they are dyed for commerical appeal.

Relationships

Sponges have different relationships with the marine and freshwater life around them. In some cases, other animals are protected by the sponge and live inside them, hiding from preditors. Some sponges attach themselves to corals and reside there until they die. This relationship though, is detrimental to the coral reef as the toxins and chemicals released injure and kill the coral. The sponges however, cannot determine where they land as they are at the mercy of the ocean currents.

Reproduction and Movement

Sponges are neither male or female and do not have any specialized reproductive organs. They reproduce both sexually and asexually. Asexual reproduction needs only one parent and one sponge does not need to come into contact with another. This form is called budding. A piece of a sponge breaks off and forms an entirely new one identical to it's parent.

During sexual reproduction the sperm is released by the "male" sponge and enters the "female" sponge. The sperm cells enter the sponge through the outer pores, where the sperm will fertilize the egg. The egg will turn into little larvae that will eventually attach itself to the ocean floor and grow into an adult sponge. Sponges must be adult to produce another sponge. An adult sponge is considered to be 3 years old.

In terms of movement, sponges are immobile. Their travel depends entirely on the moving water currents. Once a sponge finds a suitable home, it will attach itself and continue to grow and reproduce.

Respiration and Digestion

Each cell in a sponge 'breathes' independently and as a result, sponges can maintain about 68% to 99% of the useful matter that they intake. In terms of oxygen, 75% of oxygen is maintained from the water that passes through them. Essentially, sponges breathe in a number of steps:

1. Water comes into contacts with the sponge.
2. The water is absorbed through the pores on the outer layer of the sponge.
3. Flagellated structures absorb the oxygen and then pass it over to the archaoecytes which function as any type of cell.
4. The archaoecytes transport the oxygen to other areas of the sponge through canals; the rest is immediately absorbed through the cell membranes.
5. Water and gases that are no longer needed are pumped through the atrial cavity and out the osculum.

The type of respiration that a sponge utilizes is also known as osmosis.

Water enters by the sponge's pores and flows through chambers called flagellated chambers. The chambers are named this because every cell that lines them have a flagellum, a long thread that whips around to help the water flow. As no. 5 states, when water and such has served it's purpose, it leaves the sponge through the osculum.

Feeding

Sponges obtain nourishment by the filter feeding mode of life. They feed by 'filtering' tiny particles (sometimes bacteria) out of the water which is pumped through their body by their collar cells. Throughout a day, a huge amount of water is processed. For example, a 10 cm Leucandra, a type of sponge, pumps up to 22.5 litres per day. The sponge's body shape is made so that the water passes directly over the cells which are responsible for the gathering of food and gas exchange. As the small particles of food are being captured, waste and reproductive products are being removed. The collar cells digest the food and pass them into the body by specialized cells.

Because of the toxins and chemicals sponges are able to produce, they are protected by many preditors. Nudibranchs are a remarkable type of animal which has become immune towards the sponges toxins and are also able to use the chemicals in their own defense.
Many virus's and bacteria have the power to cause disease to sponges and in the 1930's a disease caused by fungi attacked commerical bath sponges and almost killed them all.

Useful Vocabulary

acelluar - without cells
spongin fibres -flexible skeletal material made up of protein
spicules - supportive needles made up of calcium carbonate
invertebrates - an animal that lacks a backbone
Porifera - the phylum in which sponges are classified in (the Hexactinellida (glass sponges), the Demospongia, and the Calcarea (calcareous sponges))
collar cell - cells that line the interior of the sponge
osculum - a large hole through which water leaves the central cavity of a sponge
amebocyte - the sponge cell that builds spicules from calcium carbonate or silica
spongin - protein that makes up the skeleton of some sponges
gemmule - sphere-shaped collection of amebocytes surrounded by spicules which can grow into a new sponge
budding - asexual reproduction in sponges

Habitat (Where they live, adaptations)

Sponges can be found in almost all water habitats. Although most reside in marine bodies of water, up to 150 different species of sponges have adapted to freshwater climates. Many sponges contain a toxic substance to discourage predators and so other marine animals protect themselves by attatching a sponge to their body where it can grow.

Sponges keep their personal space by releasing the chemicals which avoids competition. Sponges also provide a protective home for many small marine plants, which reside around the sponges pore systems. Some attach themselves to certain corals and molluscs although this is detrimental to the reefs and molluscs. Both degrade and eventually die due to the chemicals and toxins released by the sponge.

Defining Characteristics

Although there are over 5000 different types of sponges residing in the world, they each share similar characteristics. Sponges have a system of pores (also known as ostia) and canals which allows water to pass through freely. This water carries nutrients and oxygen which is vital for the sponge to live. Water also helps waste products to flow out. The movement of the water is initiated by flagellae which are found on special cells known as collar cells.

Sponges can be radially symmetrical or asymmetrical depending on simply their shape. They are held up by a skeleton made up of the protein collagen and spicules. Skeletal elements, choanocytes, and other cells can be found in a jelly like matrix called mesohyl (also known as mesoglea). Sponges have the least complex kind of cellular organization found within parazoans.

General Anatomy

A sponge, although not seeming complex has it's very own complicated body and life style. The anatomy of a sponge is composed of two outer body layers which are thinnly seperated by a gel layer, also called the mesohyl, which is acellular. Spicules or spongin fibers make up the gel layer. Different classes of sponges appear as different shapes but the life functions remain the same as sponges lack both organs and tissues. Sponges are invertebrates and their size ranges from a few milimeters up to two meters tall!






Some examples of spongin shapes:

• tubes
• fans
• cups
• cones
• blobs
• barrels
• crusts