Martin Hacala Jr., age 11, of Toronto, Ontario, Canada, for his question:
HOW DOES A SPONGE DEVELOP?
Most of the so called sponges you buy in stores today are not true sponges. Instead, they are synthetic materials made to look and to clean like true animal sponges. True sponges, however, are available commercially. These sponges can absorb large amounts of water and have qualities that make them excellent cleaning tools.
At one time it was believed that sponges were plants because they are attached to the bottom of the ocean and do not move around. Actually, a sponge is a water animal.
Sponges form an animal phylum called Porifera, which means pore bearers. The surface of a sponge's body is covered with lots of tiny pores.
Sponges can be found in all seas and in either shallow or deep water. More kinds and numbers of sponges live in the warm temperate and tropical waters than anywhere else.
A sponge will start life as a single cell, an egg.
This egg divides inside the body of the parent and keeps dividing until it forms a tiny larva or undeveloped animal form. It is covered with flagellated cells.
Then water circulating through the parent's body sweeps the larva outside the body. The tiny larva is then on its own. Its beating, lashing flagella move the larva through the water until it finally settles to the bottom of the ocean where it attaches itself to a hard surface. The larva develops into an adult sponge there.
Some sponges reproduce asexually, or without eggs. They do this by growing buds and branches that eventually break away from the parent sponge and grow into new sponges of their own.
Sponges have powers of regeneration, meaning they can regrow body parts. Even if much of the body breaks or is cut away, the sponge can replace the broken parts.
To test the regeneration powers, zoologists have pressed sponges through fine cloths so that all the cells of the sponge separate or divide into small groups. When the zoologists put the cells back into the water, the cells rearranged themselves to form a new sponge.
Many sponges come from Tarpon Springs off Florida's west coast and from the waters off Key West, the Bahamas and Cuba. Lots also come from the Mediterranean Sea off the coasts of Egypt, Greece, Tunisia and Turkey.
Sponge fishermen in the deeper waters of the Mediterranean Sea and the Gulf of Mexico use diving suits to harvest their crops. In the shallow waters off the coast of Florida they use a hooking method that involves a glass¬bottom boat and a long pole with a pronged hook.
Sponges are spread out until the flesh decays. After all the decaying substances are removed, the fishermen hang the skeletons to dry.