How does a sponge reproduce?

Sponges can reproduce sexually and asexually. If a sponge reproduces asexually it does not need a, er, partner. It either buds (a small bud is formed on a sponge before it drops from the sponge and becomes its own new sponge.) or regenerates. When a sponge regenerates you should picture a starfish. Most people know that if you cut off a starfish's leg, another will grow in its place, and the cut off leg will become a new starfish. Well, that's pretty much what happens here. A sponge loses (whether purposely or not) a limb of some sort, and then the limb grows into yet another sponge. Some sponges have sexes, but most are hermaphrodites, or are sexless.

However, most sponges reproduce sexually by releasing sperm cells into the water to fertilize ova. The fertilized eggs form larvae that swim away in search of places to settle.