MCQ Trivia On Phylum Porifera (Sponges)

Sponges are filter feeders as adults because they obtain their food by filtering water and extracting small particles, such as bacteria and plankton, from it. They have specialized cells called choanocytes that create a water current and trap food particles with their flagella. The trapped particles are then ingested by the sponge's cells for nutrition. This feeding method is essential for the survival and growth of adult sponges.

Poriferans are entirely aquatic and as adults sponges are sessile.

Spicules are small, needle-like structures that form the support structure of the skeleton in certain organisms such as sponges. They can be composed of either calcium (calcareous) or silicon (siliceous). These spicules provide rigidity and support to the organism's body, helping to maintain its shape and structure.

Scypha has a syconoid body form. The syconoid body form is characterized by a tubular body with numerous radial canals that branch out from a central cavity called the spongocoel. The walls of the canals are lined with choanocytes, specialized cells that create water currents and filter food particles. This body form is found in certain sponges and represents an intermediate stage between the simpler asconoid form and the more complex leuconoid form.

Leuconoid is the correct answer because it is a body form found in sponges. Sponges can have different body forms, including asconoid, syconoid, and leuconoid. The leuconoid body form is the most complex and efficient for filter feeding, as it has a highly branched canal system that allows for increased water flow and nutrient uptake. This body form is characterized by numerous small chambers and canals, providing a larger surface area for filtration and absorption of food particles.

Embedded in the skeleton are flagellated cells called choanocytes. Choanocytes are specialized cells found in sponges that have a collar of microvilli surrounding a single flagellum. They play a crucial role in filter feeding by creating water currents and capturing food particles. Choanocytes also have a role in reproduction and maintaining the overall health of the sponge.

Sponges can reproduce both sexually and asexually. While asexual reproduction is more common in sponges, they also have the ability to reproduce sexually through the release of eggs and sperm into the water. This allows for genetic diversity and the formation of new individuals. Therefore, the statement that sponges can only reproduce asexually is incorrect.

Scypha (Grantia) belongs to the class Calcarea.

Sponges are usually monoecious, meaning that they have both male and female reproductive organs in the same individual. This allows them to produce both eggs and sperm, increasing their chances of successful reproduction. Monoecious organisms have the ability to self-fertilize or cross-fertilize with other individuals, depending on environmental conditions. This trait is common in sponges and helps to ensure the survival and continuation of the species.

Asconoid forms have choanocytes lining the spongocoel. The spongocoel is the central cavity or chamber within a sponge where water is drawn in and expelled. Choanocytes are specialized cells that line the spongocoel and have flagella that create water currents, allowing the sponge to filter feed and obtain nutrients. Therefore, the correct answer is Spongocoel.

Leucoslenia belongs to the class Calcarea.

Euplectella belongs to the class Hexactinellida. This class is also known as glass sponges, characterized by their intricate skeletal structure made up of silica spicules. Euplectella, commonly known as the Venus' flower basket, is a type of glass sponge found in the deep sea. Its delicate and symmetrical lattice-like structure makes it a unique and beautiful organism.

Sponges are not eumetazoans. Eumetazoans are animals that have true tissues and organs, while sponges do not have these characteristics. Sponges are considered the simplest multicellular animals and belong to the phylum Porifera. They lack true tissues and organs, instead consisting of specialized cells that perform different functions. Therefore, the statement "Sponges are eumetazoans" is false.

Metazoans are multicellular animals. This means that they are organisms composed of multiple cells, which work together to form tissues and organs. Unlike unicellular animals, which are made up of a single cell, metazoans have specialized cells that perform different functions within the organism. This multicellular organization allows metazoans to have more complex structures and perform more specialized tasks, such as digestion, respiration, and reproduction. Therefore, the correct answer is that metazoans are a group of multicellular animals.

Spongin refers to a fibrous protein found in the skeletal structure of certain marine animals, particularly sponges. It provides support and structure to the sponge, acting as a framework for the sponge's cells. Spongin is flexible and elastic, allowing the sponge to withstand water currents and maintain its shape. It is different from the mineral-based spicules that some sponges possess.

Pinacocytes are the correct answer because they are the flattened cells that cover the skeleton of sponges. These cells form a protective layer over the sponge's skeleton and help maintain its structure. Choanocytes, on the other hand, are specialized cells involved in filter feeding, while archaeocytes are amoeba-like cells that play various roles in the sponge's physiology, such as digestion and regeneration. Therefore, pinacocytes are the most appropriate answer in this context.

The genus of this sponge is Euplectella.

Leuconoid sponges have choanocytes lining the choanocyte chambers. Choanocytes are specialized cells that have a collar of microvilli surrounding a flagellum, which helps create water currents and filter food particles. These choanocytes are found within the choanocyte chambers, which are interconnected chambers where water flows through. This arrangement allows for efficient water filtration and feeding in leuconoid sponges.

The correct answer is Spongia because the question asks for the genus of the sponge and Spongia is a genus of sponges.

Syconoid sponges have choanocytes lining the radial canals. Choanocytes are specialized cells that create water currents and filter food particles in sponges. In the syconoid sponge body plan, the radial canals are present, and these canals are lined with choanocytes. The choanocytes help in capturing food particles from the water that enters through the pores and channels of the sponge. Therefore, the correct answer is radial canals.

Spongia belongs to the class Demospongiae. This class is one of the largest and most diverse classes of sponges, comprising over 90% of all known sponge species. Demospongiae are characterized by their soft, spongy consistency and a skeleton made of a flexible protein called spongin or a combination of spongin and mineral spicules. They are found in a wide range of habitats, including freshwater and marine environments, and play important ecological roles as filter feeders and habitat providers.

Some sponges have the ability to produce environmentally resistant capsules called gemules. These gemules serve as a survival mechanism for the sponges, allowing them to withstand harsh conditions such as drought or extreme temperatures. Inside the gemules, the sponge cells are protected and remain dormant until conditions become favorable again. This enables the sponge to survive and reproduce even in challenging environments.

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Calcareous spicules are small, needle-like structures made of calcium carbonate that are found in certain marine organisms such as sponges and some types of plankton. These spicules provide structural support and protection for the organisms. They are formed by the precipitation of calcium carbonate from seawater, which accumulates and hardens over time. Calcareous spicules are an important characteristic feature of these organisms and play a role in their survival and adaptation to their marine environment.

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Sponges exhibit three body forms: asconoid, syconoid, and leuconoid.