Phylum Porifera MCQ Questions With Answers

The name Porifera means "pore bearer". This is because Porifera is the scientific name for sponges, which are multicellular organisms that have many tiny pores or openings on their bodies. These pores allow water to flow through the sponge, enabling them to filter out food particles and oxygen. Therefore, "pore bearer" accurately describes the characteristic feature of sponges.

Sponges reproduce both sexually and asexually. They can reproduce asexually through a process called budding, where a small part of the sponge grows and eventually detaches to form a new individual. They can also reproduce sexually by releasing eggs and sperm into the water, where fertilization occurs externally. This allows for genetic diversity and the production of offspring with different traits.

Porifera, or sponges, exhibit asymmetrical symmetry, lacking a specific symmetry plane. Their bodies lack a consistent arrangement of body parts, and they don't display radial or bilateral symmetry. Instead, their structure is irregular and varied, making them an example of asymmetry in the animal kingdom.

Most of the members of phylum Porifera are marine animals, but there are also a few that are found in freshwater environments.

Spicules are the hard "skeletal" structures found in sponges. These structures provide support and structure to the sponge's body. Spicules are typically made of calcium carbonate or silica and vary in shape and size depending on the species of sponge. They help to maintain the sponge's shape and provide protection against predators.

The flagellum is responsible for setting up a water current in a choanocyte. Coanocytes are specialized cells found in sponges that have flagella, which are whip-like structures that can beat and create a flow of water. The movement of the flagellum creates a current that brings in oxygen and small molecules, while also carrying away carbon dioxide and ammonia. This allows for the efficient exchange of gasses and nutrients within the sponge's body.

The outer layer of a sponge is composed of pinacocytes. Pinacocytes are flat cells that form a protective covering over the sponge's body. They are responsible for maintaining the structure and integrity of the sponge, as well as regulating water flow and gas exchange. These cells are tightly packed together, forming a barrier that helps to prevent the entry of foreign particles or organisms into the sponge's internal cavity.

Sponges have innumerable mouths, meaning they have multiple openings through which they can take in water and filter out nutrients. However, they only have one exit through which waste and filtered water are expelled. This unique characteristic allows sponges to efficiently capture food particles and remove waste from their bodies.

Sponges are filter feeders that obtain their food by filtering water through their bodies. They primarily feed on detritus, which includes dead organic matter and waste particles. Sponges also consume plankton, which are microscopic organisms drifting in the water. Additionally, some sponges are capable of ingesting viruses, which they can digest and obtain nutrients from. Therefore, the correct answer is "all of the above" as sponges have the ability to eat detritus, plankton, and viruses.

Poriferas, also known as sponges, are multicellular organisms that lack true tissues and organs. They have a unique body structure characterized by a system of pores and canals, a perforated body, and choanocytes, which are specialized cells involved in filter feeding. However, not all Poriferas possess spongin fibers. Spongin fibers are a type of protein that provide structural support to some sponge species, but they are not present in all Poriferas. Therefore, the presence of spongin fibers is not typical to all Poriferas.