what are the general life cycles of porifera?

Answer 1

Phylum Porifera includes the sponges.

Sponges produce eggs and sperms in a single organism. They are hermaphrodites. The eggs usually stay in the body of the sponge while the sperms are released into the water. Sperms enter another sponge through the incurrent pores and fertilize the eggs.

The fertlized eggs develop into the larvae which are free-swimming. This is a really good plan for organisms that are sessile, that don't move around. The larvae can move off to some area that is away from the parents so they don't have to compete as much for resources. The larvae settle to a surface and grow into adult sponges.