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Classification of Phylum Porifera. Phylum Porifera is classified into three classes: Calcarea. They are found in marine, shallow, and coastal water. Their skeleton is composed of calcareous spicules made of calcium carbonate. The body is cylindrical and exhibits radial symmetry. The body organization is asconoid, syconoid, or leuconoid.
- The phylum has the following distinguishing characteristics: These are pore-bearing multicellular animals. The body has no organs. They exhibit hol...
- Poriferans include: Sycon Spongilla Hylonema Cliona
- Sponges are found in shallow water and deep seas, but are always found attached to the floor of the sea. They can be found at a depth of more than...
- Poriferans exhibit holozoic nutrition. They filter the tiny, floating organic particles and planktons that they feed on, hence called filter-feeder...
- Poriferans are attached to the seafloor and cannot move from one place to the other. Since they share this characteristic with plants, they are oft...
- Since sponges are attached to the sea bed, they act as a habitat for several commercially important species, thereby maintaining the biodiversity o...
- Sponges do not have chlorophyll and cannot prepare their own food. They capture different organisms for nutrition. Most of the sponges that reprodu...
- Sponges are of three types: Asconoid Synconoid Leuconoid
- The classification of Porifera into Calcarea, Hexactinellids and Desmospongiae is based on the presence of their exoskeleton.
Oct 31, 2023 · Phylum Porifera (“pori” = pores, “fera” = bearers) are popularly known as sponges. Sponge larvae are able to swim; however, adults are non-motile and spend their life attached to a substratum through a holdfast. The majority of sponges are marine, living in seas and oceans. There is, however, one family of fresh water sponges (Family ...
The simplest of all the invertebrates are the Parazoans, which include only the phylum Porifera: the sponges (Figure 28.1.1 28.1. 1 ). Parazoans (“beside animals”) do not display tissue-level organization, although they do have specialized cells that perform specific functions. Sponge larvae are able to swim; however, adults are non-motile ...
Phylum Porifera – Biology - UH Pressbooks is a chapter that introduces the characteristics, diversity, and ecological roles of sponges, the simplest animals in the animal kingdom. Learn how these aquatic organisms filter water, reproduce, and adapt to different environments. This chapter is part of a free online textbook that covers the major topics of biology.
- Habitat
- Sessile Like Plants
- Canal System
- Multicellularity
- Spongocoel
- Mode of Nutrition
- Food Digestion
- Reproduction
- Fertilization and Development
- Types
All the poriferans are free-living aquatic animals. The majority of them exist in marine habitats except for the members belonging to the family Spongillidae, which live in freshwater lakes and streams. They can thrive in shallow ocean environments to depths as great as five kilometres.
The mature sponges are sessile and sedentary, i.e. they are permanently affixed to the solid substratum like clamshells and rocks. Like plants, they cannot move here and there or attach firmly to the sea bed. Their body shape is non-uniform and asymmetrical.
The outer surface is punctured by innumerable pores or ostia that provide channels for the entry of water. Also, there are a few wide openings calledoscula that spill excess water. In several freshwater sponges, the contractile vacuoleis also present. Thus, sponges can absorb and withhold fluids.
Sponges are the lower multicellular organisms without having distinct tissue and organ system. They are cellular and diploblastic organisms. Their body wall divides into an outer pinacoderm (derived from epithelial cells) and an inner chaonoderm (derived from endothelial cells) by having a mesenchyme layerin between. Sponges deprive an excretory, r...
Paragaster or spongocoel is an interior space of porifers, which appear as a hollow cavity. Sometimes, it is infused with several canals lined by collar cells with a thread-like flagellum.
It is holozoic, where the specialized collar cells of sponges primarily filter the suspended food particles from the water and later internalize the tiny and suspended food particles. Then, amoeboid cells pass them to the other cells for digestion. Due to this fact, sponges are also known as filter feeders.
They lack a mouth and digestive cavity. Amoeboid cells in the mesenchyme layer mediate the movement of planktonic food and water throughout the body. The mechanism of digestion is intracellular, occurring inside the food vacuole of collar cells. Thesocytes store the food content.
It occurs by both asexual and sexual methods. Asexual reproduction occurs by budding, while sexual reproduction occurs via ova and sperms. The side or base of the sponges protrudes out through budding. Eventually, new organisms form as the extended bodies detach. All sponges are hermaphroditescontaining both male and female sexual properties. Spong...
Fertilization is generally internal that occurs in the mesenchyme. However, cross-fertilization can also take place. The process of development is also indirect by a free-swimming, ciliated-larva called amphiblastula or parenchymula. Cleavage is generallyholoblastic.
Ascon, sycon, and leuconoid are the common types. The internal skeleton may comprise either fine spongin fibres, siliceous spicules, or calcareous spicules. Examples: Sycon, Grantia, Hyalonema, Cliona, Spongilla, Euspondia, etc.
Aug 3, 2023 · Porifera Definition. The Porifera may be defined as an asymmetrical or radially symmetrical multicellular organism with a cellular grade of an organization without well- definite tissues and organs; exclusively aquatic; mostly marine, sedentary, solitary or conical animals with body perforated by pores, canals, and cambers through which water flows; with one or more internal cavities lined ...
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Aug 24, 2022 · Sponges are unique creatures. They are in the Phylum Porifera and there are about 5,000 different known species. They are one of the simplest forms of multi-cellular animals and come in a variety of different colors, shapes, and sizes. Sponges lack organs and a nervous system. They are sessile organisms, attached to reef surfaces via a holdfast.
