Sponges are uncomplicated aquatic invertebrate animals that are categorized within the Phylum Porifera, the lowest multicellular members of the Animal Kingdom, comprising approximately 5000 species. These creatures, known as Poriferans, possess small openings called 'Ostia' distributed throughout their bodies. Their sponge-like structures are capable of absorbing and retaining fluids.
Sponges typically remain affixed to the substrate and do not exhibit mobility. Due to this immobility, they were initially mistaken for plants. However, subsequent discoveries regarding their life cycle and feeding mechanisms unequivocally confirmed their classification within the animal kingdom. Continue reading to uncover more fascinating details about the general characteristics of poriferans.
The Phylum Porifera are sedentary, primarily marine, radially symmetrical, or asymmetrical, multicellular organisms without definite organ systems. It is the lowest multicellular animal belonging to the kingdom Animalia, and these are pore bearers or pore bearing species. Earlier, these species were regarded as plants due to their green colour and similarity with algae, but after discovering their life cycle and feeding system, they are included in the animal kingdom.
In the below sections, we will read about the history of Porifera.
Sponge
Porifera is a phylum that belongs to the Kingdom Animalia and is commonly known as sponges. The sponge or poriferans, named from Latin porus to “pore” and ferre to “bear”, believed that they are the simplest animals on the earth because they do not have true tissues such as muscles, nerves, and internal organs. So, many scientists who study this animal separated them from other Metazoans to the phylum of the Parazoa branch of Kingdom Animalia.
The characteristic features of the Phylum Porifera are as follows:
Labeled Diagram of Sponge
In sponges, the canal system is of three types and is as follows:
i. Asconoid Canal System: It is the simplest type with thin walls. Spongocoel is large and spacious. Choanocytes form the gastral layer and line the whole spongocoel.
Route of water: This type is seen in Leucosolenia.
ii. Syconoid Canal System – It is a complex type with thick walls. Spongocoel is narrow and choanocytes are restricted in radial canals only.
Route of water: This type is seen in Grantia.
iii. Leuconoid Canal System – It is a much more complex type with highly folded thick walls. Spongocoel is either reduced or absent. Choanocytes are confined in the flagellated chambers which are formed by the evagination of radial canals.
Route of water: This type is seen in Plakina.
Reproduction in Sponges
Asexual Reproduction: This mainly occurs by fragmentation, budding and gemmules.
Sexual Reproduction: Sexual reproduction in sponges occurs when gametes are generated. This type occurs with the help of amoebocytes or archaeocytes or sometimes through choanocytes.
These are hermaphrodites, development is indirect with a larval stage called amphiblastula or parenchymula.
Phylum Porifera is classified into three classes as follows:
1. Calcispongiae or Calcarea
2. Hyalospongiae or Hexactinellida
3. Demospongiae
Some of the major examples of the phylum Porifera are given below:
Sycon
Spongilla
Hyalonema
Some of the economic importance of the phylum Porifera are as follows:
Within the Kingdom Animalia, the Phylum Porifera stands as one of the phyla. This particular phylum is distinguished by its members, which are characterized as pore-bearing organisms and commonly referred to as sponges. Sponges are hermaphroditic in nature and are aquatic animals with an asymmetrical body structure, exhibiting a wide range of colors, shapes, and sizes.
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1. What is the definition of Phylum Porifera? |
2. What is the history of Porifera? |
3. What are the types of canal systems found in sponges? |
4. How do sponges reproduce both asexually and sexually? |
5. How are Phylum Porifera classified? |
6. What is the economic importance of Phylum Porifera? |
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