Question

Proterospongia is the link between ______.
(A)Sponges and Coelenterates
(B)Coelenterates and aschelminthes
(C)Protozoa and Porifera
(D)None of the above

Answer 1

Hint Proterospongia is an organism that forms colonies which helps to distinguish between each species as every species forms a different type of colony. They belong to the class choanoflagellates and family codonosigidae.

Complete answer:
Proterospongia is the link between the two phyla- protozoa and Porifera. It belongs to the class choanoflagellates and is a single-celled aquatic colony-forming organism. As its name suggests, some features of the genus represent that of the poriferans whereas some represent that of protozoans.

Additional Information:
Below are the characteristics of the genus Proterospongia:
-Body is of choanoflagellate cell structure 5-10 micrometer in diameter and has an apical flagellum surrounded by the collar of microvilli.
-Flagella helps in swimming and microvilli helps in creating water current to capture food.
- Arrangement of organelles characterized by an anterior dictyosome under the flagellar base with a central nucleus, peripheral mitochondria, and posterior food vacuole.
-They are characterized by colony morphology that varies from species to species and can be simple chains of cells to astral assemblages
-Colonies contain extracellular mucilage.
-The life cycle of these organisms alternates between colonial and swimming and adherent solitary states.

So, the correct answer is "Protozoa and Porifera".

Note: According to Kent as he stated in the Infusoria, there are six different species of Proterospongia but only one species i.e. P. choanojuncta has a described life history. It is very interesting that colony structure varies from each species to species. The scientists that study mechanisms of Intercellular signaling and adhesion, hold a special interest in Proterospongia as it forms colonies.