Sponges

• Sponges are the simplest of the multicellular animals. • They have no organ systems• They are assymetrical• They have no nervous system• They are characterized by numerous canals and chambers that open to the

outside by way of pores – Pores - tiny openings giving this phylum its name.

Most sponges are marine

Body Plan of sponges

• Water (carrying suspended plankton) enters small pores called ostia (singular, ostium).

• water flows directly into an open chamber called the spongocoel (coel - open space or body cavity in an animal).

• Water leaves the spongocoel by a larger opening (the osculum).

Body Plan of A Typical Sponge

part of a colony

Collar cells

Simple Organisms without complex organ systems or nervous systems

• The interior of the spongocoel is lined with flagellated cells called choanocytes .

• A flagellum extends from the center of this collar, the movement of which creates currents that force water through the sponge's "plumbing system".

How do sponges feed?

Sponges are Filter Feeders

Elephant Ear Sponge

There are about 10,000 species of sponges

Amoebocytes

• responsible for producing the sponge's skeleton – a network of fibers, spongin (flexible protein) and

needle-like spicules• spicules are usually made of calcium carbonate

or of silica

Protection

Some sponges produce toxinsThe purpose of these toxins is to ward off predators that would feed on the sponges.

Reproduction in Sponges

Asexual - budding and fragmentationSexual reproduction is timed to environmental

cues such as water temperature, tides, and the phase of the moon.

Reproduction • Most sea sponges are hermaphroditic (having both

sexes in one), but produce only one type of gamete per spawn.

• The sperm is released into the water column by the "male" sponge and finds its way to the "female" sponges, where fertilization occurs internally.

• The planktonic larvae are released from the female sponge and float around in the water column as plankton for only a few days.

• They then settle down (become sessile) and start growing.

Characteristics of Porifera1)No definite symmetry. 2)Body multicellular, no tissues, no organs. 3)Cells surround a water filled space but there is no true body cavity. 4)All are sessile, (live attached to something as an adult). 5)Reproduce sexually or asexually. 6)Has no nervous system. 7)Has a larval stage which is planktonic. 8)Lives in aquatic environments, mostly marine. 9)All are filter feeders. 10)Often have a skeleton of spicules.

Medical Research

The World Health Organization (WHO) estimates that 300 million to 500 million cases of malaria occur annually, mostly in developing countries near the equator, and that the disease claims a million lives a year. Tuberculosis infects about a third of the world's population and kills an estimated 3 million people each year.

Several sponge species of sponges produce compounds that show great promise as a drug to combat malaria, tuberculosis and other infectious diseases.

Many compounds extracted from sponges have also anti-viral and anti-cancer properties. Back in the 1950s, chemists found compounds in a sponge in the waters off the coast of Florida that wound up as antiviral drugs Acyclovir (Zovirax®), to treat herpes, and Cytarabine (Cytosar®), to treat non-Hodgkin's lymphoma.

In 1998 a deep-sea sponge discovered in the waters off the Bahamas is being studied as treatment of cancers

A Japanese sponge has shown promise as a treatment for melanoma and leukemia and is currently in pre-clinical trials

A Palauan shallow-water sponge is easily synthesized and is being developed for treatment of osteoarthritis.