A Phylum of Sponges

Produced by:Produced by:Harold Feyman Harold Feyman DurezaDurezaEla Marie Sofia CelizEla Marie Sofia Celiz

WHAT IS THE PHYLUM WHAT IS THE PHYLUM PORIFERA?PORIFERA?Etymology:Etymology: From the Latin From the Latin porusporus for ‘pore‘ and for ‘pore‘ and ferreferre for ‘to bear’. for ‘to bear’. Hence, Hence, poriferaporifera for ‘an animal with pores’ for ‘an animal with pores’Etymology:Etymology: From the Latin From the Latin porusporus for ‘pore‘ and for ‘pore‘ and ferreferre for ‘to bear’. for ‘to bear’. Hence, Hence, poriferaporifera for ‘an animal with pores’ for ‘an animal with pores’

This phylum, under the kingdom Animalia, is mostly This phylum, under the kingdom Animalia, is mostly consisted of sessile sponges living in the oceans and seas.consisted of sessile sponges living in the oceans and seas.

Sponges are one of the better known groups of Sponges are one of the better known groups of invertebrates.invertebrates.

Carnivorous sponges live in fresh water while Carnivorous sponges live in fresh water while detritivore sponges are marine animals.detritivore sponges are marine animals.

They lived in the waters for more than 600 million They lived in the waters for more than 600 million years.years.

They are believed to have covered up half of the They are believed to have covered up half of the marine coral reefs during the Paleozoic.marine coral reefs during the Paleozoic.

They are considered as sedentary, filter-feeding They are considered as sedentary, filter-feeding metazoans.metazoans.

Some basic characteristics...Some basic characteristics...

• It has no definite symmetry.It has no definite symmetry.

• The body is multicellular, has few tissues and no organs.The body is multicellular, has few tissues and no organs.

• The cells and tissues and surround a water filled space but there is no The cells and tissues and surround a water filled space but there is no true body cavity.true body cavity.

• All are sessile. Some attach themselves to something as an adult.All are sessile. Some attach themselves to something as an adult.

• Reproduces sexually or asexually. The sexual reproduction can either be Reproduces sexually or asexually. The sexual reproduction can either be gonochoristic or hermaphroditic.gonochoristic or hermaphroditic.

• It has no nervous system.It has no nervous system.

• It has a distinct larval stage which is planktonic.It has a distinct larval stage which is planktonic.

• All are filter feeders.All are filter feeders.

• It often has a skeleton of spicules.It often has a skeleton of spicules.

The body of a sponge is a collection of a few different types of cells that are closely arranged in a gelatinous matrix called a mesohyl, mesoglea, or a mesenchyme.

WHAT IS THIS MESOHYL?WHAT IS THIS MESOHYL?

A mesohyl is a connective tissue of a sponge body wherein A mesohyl is a connective tissue of a sponge body wherein it is supported by skeletal elements. It functions as an it is supported by skeletal elements. It functions as an endoskeleton (internal skeleton of an animal) in most sponges, endoskeleton (internal skeleton of an animal) in most sponges, and is the only skeleton in soft sponges that encrust hard surfaces and is the only skeleton in soft sponges that encrust hard surfaces as rocks.as rocks.

There are two kinds of skeletons that the poriferans have: There are two kinds of skeletons that the poriferans have: exoskeletonexoskeleton and and endoskeletonendoskeleton..EndoskeletonEndoskeleton

Like vertebrates, sponges also have endoskeletons. Like vertebrates, sponges also have endoskeletons. Endoskeletons, as said from the previous slide, is the internal skeletal Endoskeletons, as said from the previous slide, is the internal skeletal system. In sponges, it is actually a layer of covering cells. The layer that system. In sponges, it is actually a layer of covering cells. The layer that these cells form is called a these cells form is called a mesohylmesohyl. This mesohyl is usually stiffened by . This mesohyl is usually stiffened by mineral spicules, spongins fibers or both. mineral spicules, spongins fibers or both. ExoskeletonExoskeleton

Some sponges also excrete exoskeletons. These exoskeletons are Some sponges also excrete exoskeletons. These exoskeletons are layers of flagellated cells. They lie completely outside their organic layers of flagellated cells. They lie completely outside their organic components. For example, sclerosponges or “hard sponges” have massive components. For example, sclerosponges or “hard sponges” have massive calcium carbonate exoskeletons. Pinacocytes from the animal’s skin calcium carbonate exoskeletons. Pinacocytes from the animal’s skin excrete the exoskeletons.excrete the exoskeletons.

WHAT ARE THESE SO-CALLED SPICULES?

• They are hard, crystal-like spines that support skeletal-like structures.

• Normally, they work in conjunction with spongins which are protein that forms a tough fibrous network throughout the sponge.

• They are also non-living aggregates of a chemical nature that are made from either silica, or calcium carbonite.

• They are important in the classification of sponges.

CLASS CALCAREACLASS CALCAREA

•The calcareous sponges of phylum Porifera is identified to have 2 to 4 The calcareous sponges of phylum Porifera is identified to have 2 to 4 points on the spicule.points on the spicule.

• All species are marine dwellers.All species are marine dwellers.

• All sponge body plans are represented by this class: asconoid, All sponge body plans are represented by this class: asconoid, syconoid, leuconoid.syconoid, leuconoid.

• They are very small, usually 3-4 inches in height.They are very small, usually 3-4 inches in height.

• There are 400 species existing of this class.There are 400 species existing of this class.

• Generally lack hollow canals.Generally lack hollow canals.

• They are sedentary filter feeders.They are sedentary filter feeders.

• Their body type can either be radially symmetrical or irregular.Their body type can either be radially symmetrical or irregular.

CLASS DEMOSPONGIAECLASS DEMOSPONGIAE

• The largest class in phylum Porifera.The largest class in phylum Porifera.

• They contain 90% of all species of sponges.They contain 90% of all species of sponges.

• Predominantly, their structures are Predominantly, their structures are leuconoid.leuconoid.

• Most are marine dwellers but several live in Most are marine dwellers but several live in freshwater areas.freshwater areas.

• They reproduce both sexually and asexually.They reproduce both sexually and asexually.

CLASS HEXACTINELLIDACLASS HEXACTINELLIDA

• These are sponges with a skeleton made of four or six pointed silaceous spicules.

• They are often referred to as glass sponges.

• They are relatively uncommon and most are found at substantial depths.

• They are usually cup-shaped animals with sturdy endoskeletons made up of fused spicules.

• They have a unique system for rapidly conducting electrical impulses through their bodies, making them easy to respond to external stimuli.

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