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Phylum Porifera Sponge Lyrics and Vocal: Shin Kubota, Music: Gouki Okabe, Arrangement: Toshio Nakagita |
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In the Mediterranean Sea area, a naturally-made body washing sponge (Spongia) has been used since the Roman era. This species has a soft body because it lacks geometrically structured hard spicules that are unique to sponges. Moreover, it has high capacity for regeneration. If you cut sponge into pieces and hang them in the sea, eventually they will grow to many natural sponges. In contrast, coral-like hard sponges have dwelled in underwater caves as a survivor from the Paleozoic era. Animals which belong to the porifera have existed for six hundred million years and have kept their primitive body structure. Unlike other multi-cellular animals whose cells are tightly connected, sponge cells are loosely aggregated. Thus, amazing ability of the sponge can easily be demonstrated in laboratory. If you place a sponge in a bowl, grind them down into tiny pieces, strain them through a fine sieve, place them in a petri dish filled with clean seawater, and leave them quietly for a while. The scattered tiny cells will start gathering to form an aggregate and become small sponges. If two sponges of different colors were grind together, they do not form a mixed sponge, but each kind of sponge fragments crawl separately on the bottom of the petri dish to regenerate the sponge bodies that are visibly different with the naked eye. In fact, the sponges can recognize self and non-self and become sessile without muscles, nerves nor sensory organs. There are approximately nine thousand species of sponges in the world. A large majority of them lives in the sea from the bottom of the deep sea to coastal areas and from tropical waters to polar seas. Only about 150 species of sponges live in freshwater. If you look closely at ropes on floating piers, tires, and buoys, you may find many colorful sponges covering the surface like mosses. The Venus' flower basket, which looks like a cone shaped base or a long narrow glass sculpture, may be found inside a fishing gear abandoned at the bay. Halichondria okadai (dark gray coastal sponge) or H. japonica (orange coastal sponge) can easily be found on the reefs of rocky coasts during low tide. If you dive in the tropical sea, you may find a gigantic barrel sponge which is large enough for an adult human to fit inside. Large holes looking like craters sparsely appeared in the sponge’s surface are excurrent openings (osculum) used for spewing out inhaled water. Each sponge has several excurrent openings and numerous incurrent openings (ostium) which are too small to see with the naked eye. It has a network of elaborate waterways and collar cells (choanocytes) which surround many choanocyte chambers in mid stream. Fllagela on the collar cells generate water flow and catch organic debris and microbes. In recent years, a unique species of sponge has been discovered from an underwater cave about 20 meters deep in the Mediterranean Sea. It is a carnivorous species which captures small shrimps with hooks on the body surface like an insectivorous plant. This species does not have collar cells, incurrent and excurrent openings that are unique to the Porifera. In contrast, mobile Sea Orange (Tethya aurantium) is an orange, ball-shaped sponge about 3 cm in diameter. It spreads string-like extensions from the body surface and attaches the tip of the extensions to a hard surface while creating clones as the parental body moves. Life cycles of only a few species of sponges are known and most of them are hermaphroditic. Free swimming sperms from other individuals are captured by collar cells. The sperms are, thorough such cells, transported into where the eggs are located, and then fertilization takes place. A ciliated gastrula stage larva grows and swims out in the sea, and eventually it attaches to a hard surface to become a mature sponge. |
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We are the sponges, Phylum Porifera |
I am sorry.
A song is only Japanese.
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