Sponge Dissection Lab:
Grantia sp, simple sponge
Procedure:
Ecology of the Porifera: Sponges have irregular shapes and many are large. Because of this, they provide habitats for marine animals like snails, sea stars, and shrimp. Sponges also form partnerships with bacteria, algae, and other plantlike protists. They provide oxygen and food for the sponge, and the sponge gives shelter and protection for the animals. Sponges usually live attached to the deep sea floor, where they receive low levels of sunlight. It is unknown to how the sponges receive sunlight to perform photosynthesis. It is guessed that the sponge has a sort of lens on the the antennae.
Groups of the Porifera: Sponges have three different groups: the calcareous sponges, the demosponges, and the glass sponges. The calcareous sponges are characterized by spicules made out of calcium carbonate in the form of calcite or aragonite. The demospongiae are the largest class in the phylum Porifera. In fact, the demosponges include 81% of all species of sponges with nearly 7,000 species worldwide. They are predominantly leuconoid in structure. Their "skeletons" are made of spicules consisting of fibers of the protein spongin, the mineral silica, or both. The glass sponge, aka the hexactinellid sponge, have a skeleton made of four to six pointed siliceous spicules, which are structures that provide support and ward off predators. They are the most uncommon kind of sponge. |