SPONGES

by N.G.

A sponge is any of a phylum (Porifera) of simple, aquatic, sessile animals having a porous structure and a tough, often siliceous skeleton.
Sponges are different kinds of animals that live in water. They don’t have most body parts that other animals usually have. They stay still. Sponges stay attached to an underwater rock or coral reef. People thought sponges were plants for a long time. Scientists decided that sponges were animals only after watching them eat food by swallowing it into their bodies.
There are about 5,000 different species of sponges. Most sponges live in oceans, but some live in freshwater. Sponges could be flat like spreading moss. They can also look like trees with branching arms. Some sponges could be as small as a bean, while others could be as tall as a person. Sponges can have all types of roughness or softness. They can be smooth and mushy, or they can be rough, hard, and prickly. Some are old and dull, but others can be brightly colored.
A sponge’s body is a soft mass of cells supported by a skeleton. Holes in sponge’s skin let water flow inside. They take food and oxygen from the water.

Sponges can be useful to people.  Some people collect sponges. They dry, clean, and trim themselves. The fleshy parts of the sponge are thrown away, and only the skeleton is used. Ancient Greeks and Romans used sponges to pad their war helmets and armor. People today still use sponges for many things such as for bathing, mopping, and painting. However, most of the sponges we use today do not come from animals. They are products that are made in factories.

 “Sponges”,     www.school.eb.com        Encyclopedia Britannica Online School   published in 2010