Haplosclerids are distributed worldwide, even in freshwater. They stand out as sponges that can tolerate an unstable home environment. You find them in places like estuaries that suffer regular changes in salinity and water levels, tropical marshes that dry up in summer, and high elevation lakes that freeze in winter. How can a sponge survive these fluctuating environments Haploscerids usually alternate between sexual and asexual reproduction, and can go asexual when conditions are bad. They produce buds made of cells and a food supply called gemmules, which are little miracle packets that can survive freezing and drying. If it gets too dry, gemmules go into a torpid state called estivation and, if it gets too cold, they hibernate. The adult sponge may die, but leave behind a bunch of gemmules that can wait and begin to grow again when conditions improve.

Because sponges contain a variety of chemicals that affect living organisms (bioactive compounds), they have become the subject of research to find drugs to treat human diseases. Haplosclerida sponges have been especially fruitful for bioactive compounds. The upwards of 30 compounds called 3-APs found in haplosclerids have properties such as keeping bacteria from growing and stopping cells from dividing. Not only might they be valuable for human medicines, but they also help the sponge stay healthy. A greasy coating of 3-AP compounds on the surface of a haplosclerid sponge is like a repellant for bacteria and other organisms that could contaminate it. The trick for our using these compounds is how to get large enough amounts without hurting wild populations of sponges. Scientists are working to synthesize (make copies of) compounds like the 3-APs rather than take them directly from sponges.