Phylum Porifera. 2. ○ Sponges. – Over 7, species, approximately 40 species that occur in local waters. – 2% of all sponges are freshwater, none are. Phylum Porifera. I. General Ecological Characteristics. Sponges are: •. Sessile, benthic. •. Filter feeders. • Competitors for space. •. Fed upon by specialist. Porifera. Cnidaria. Ctenophora. Platyhelminthes. Rotifera. Nematoda. Nemertea phyla. Pseudocoelomates. Coelomates. A Phylogeny of the Animal Phyla.
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PDF | On Jan 16, , Maldonado and others published Chapter 2. Phylum Porifera. PDF | The Porifera are a well-characterised group of aquatic, predominantly marine animals including about described species. These animals are distinct. PDF | Freshwater sponges, at present considered monophyletic, belong to the The phylum Porifera is subdivided into four recent classes.
Museu Nacional, Station 3 activity: They may also con- bution: These choanocytes which gotes that developed until the late blastula do not digest the phagocytosed spermato- stage Maldonado, personal observations. Male spawning takes places by fu- the calcareous Ascandra minchini Borojevic, sion of the spermatic cysts to the wall of the and Clathrina coriacea Jonhson, , exhalant aquiferous canals so that the ma- and demosponges of the genera Haliclona ture spermatozoa are released into the out- Fell, , Halichondria Witte and Barth- going flow and finally expelled through el, and Chondrilla Maldonado et al. Structure Spongocoel interior chamber Ostia singular:
IT w ntP F. Spirophorida F. Riesgo O. Astrophorida F. Ancorinidae G? IT w stP F. Geodiidae GO ET 2?
Pachastrellidae GO ET 3? Halichondrida F. IT, w Hp F. Axinellidae GO IT w? Hadromerida F. Hemiasterellidae G O?
Agelasida F. Spirastrellidae G? Stylocordylidae G? Haplosclerida F. Chondrosida F. Dictyoceratida 13 families; 41 genera GO ET 5? Poecilosclerida F.
IT ntP F. Dendroceratida F. Coelosphaeridae HV IT w? Halisarcida F. Verongida F. Desmacididae H? Abbreviations and symbols are as it follows: Numbers, letters and symbols in brackets refer to annotations on the condition expressed in the table, as it follows: Crambe crambe; 8: There are also described instances of choanocytes de-differentiating into archaeocyte-like cells before becom- ing recognizable spermatogonia Reiswig, In Hexactinellida, since choanocytes are enucleated cells, spermatogonia are suspected to differentiate from archaeocyte congeries e.
In most studied cases—nearly all of them belonging to the class Demospongiae—the choanocytes become spermatogonia in a chamber and maintain the flagellum dur- ing this differentiation figure 1c and sub- sequent stages.
This situation is in contrast to the model followed by most animals, in which the flagellum only appears at late stages of gametogenesis. Nevertheless, in some sponges, such as Suberites massa Di- az and Connes, and Spongia officina- lis Gaino et al. The rea- son for this transient flagellum loss could be due to the fact that spermatogonia need to multiply by mitosis in order to increase their numbers before starting gametogene- Figure 1.
The cyst envelope is quite chronous event linked to egg release and complex in some carnivorous demospong- often takes place one or only a few days a es that have lost their aquiferous canal sys- year.
Within a cyst, spermatogenesis may tem, which is the usual via for, not only be either synchronous with all cells in the food intake, but also sperm release Vacelet same spermatogenetic stage, or in a matu- and Boury-Esnault, In carnivorous, ration gradient, with spermatogonia at the canal-lacking sponges, isolated spermato- periphery of the cysts and mature sperma- zoa are not released individually.
Rather tozoa towards the lumen figure 2c. This nia experience two consecutive divisions: Similar to that seen in other an- celet, Note cytoplasmic bridging arrows between sister spermatocytes in a and c.
Primary spermatocytes nel for the flagellum, etc consistently take are easily recognizable due to their nucle- place during this phase. In be classified into two morphological types: During spermatidogenesis, In most studied cases, a set of proacro- secondary spermatocytes differentiate in- somal vesicles in the cell pole are evident to haploid spermatids.
This process is rap- opposite from the flagellum insertion fig- id and has rarely been documented in de- ure 4a. However, proacrosomal vesicles tail. The most characteristic feature is that are lacking in some species, such as Ap- cells diminish to the definitive size of the lysilla rosea Tuzet et al.
Proacrosomal vesicles the form of residual bodies. Finally, sper- are usually regarded as the evolutionary miogenesis renders mature spermatozoa prelude of the real acrosomes in higher an- from spermatids. In some sponges, the Gol- of the very distinct demosponge order Ho- gi complex releases vesicles that will par- mosclerophorida figure 4b; table 1; Baccet- ticipate in the formation of acrosomal ele- ti et al.
In some demosponges, ; Riesgo et al. Interestingly, Figure 3 facing page. Riesgo Figure 4. In cycle. They grow during a species-depen- contrast, the spermatozoon of A. Alterna- no rootlets, and that of H. Asynchrony is common carea Leucosolenia complicata Anakina and in viviparous species. Drozdov, At present, both the func- Early-stage oocytes are usually amoe- tional and phylogenetic significance of the boid cells figure 5d that may wander diverse morphologies in sponge sperm re- through the mesohyl while incorporat- main poorly understood.
As oogen- Oogenesis esis progresses, oocytes grow and become round.
The initial stages of oocyte growth Oogenesis has been described in reason- are previtellogenic, rarely involving yolk able detail in quite a few demosponges, production Fell, ; Simpson, Our some calcareous sponges e. Yolk bodies are membrane-bound and Oopsacas minuta Boury-Esnault et and show a very electron-dense core of stri- al. Nevertheless, some spe- and hexactinellids. Pinacocytes have been cies produce yolk bodies in which lipids, suggested to be the origin of oogonia in the multi-membrane structures and the rests calcareous sponge Ascandra minchini Boro- of digested microorganisms are packed in- jevic, In some calcareous species, the to atypical heterogeneous structures e.
As in other animals, ence mitotic divisions before the onset of yolk production in Porifera can take place oogenesis Fell, These pre-oogonial via autosynthesis, heterosynthesis or both divisions are not common in Demospon- processes simultaneously Riesgo and Mal- giae, although they have been documented donado, Riesgo Sponges that appear to use strict au- organisms and large incorporated com- tosynthesis are Suberites massa Diaz et al.
Others use a semi-autosyn- Yolk heterosynthesis involves participa- thetic process, in which the precursors are tion of different types of somatic cells e. Note section of endobiotic po- lychaete po in the sponge tissue.
Note also the occurrence of a spermatic cyst sc , clearly distinguishable from the choanocyte chambers ch. These cells either elaborate process Fell, In many instances, oo- yolk or its precursors in their cytoplasm cytes are surrounded by packages of striate and also incorporate extracellular micro- fibers, as in Tetilla serica and Tetilla japoni- organisms into vesicles, transporting and ca Watanabe, , by a thin layer of colla- transferring all these materials to the grow- gen fibrils, such as in Suberites massa Diaz ing oocytes figure 6e-f.
Reserve materials et al. In some instances, oocytes ap- matozoa are released into the water col- pear to phagocytose entire nurse cells, as in umn,. Male spawning takes places by fu- the calcareous Ascandra minchini Borojevic, sion of the spermatic cysts to the wall of the and Clathrina coriacea Jonhson, , exhalant aquiferous canals so that the ma- and demosponges of the genera Haliclona ture spermatozoa are released into the out- Fell, , Halichondria Witte and Barth- going flow and finally expelled through el, and Chondrilla Maldonado et al.
In addition to yolk, the cytoplasm of The process is similar for oocyte release in oocytes contains plenty of other energetic oviparous sponges. Oocytes or eggs are re- inclusions in the form of glycogen and lip- leased either individually through the os- id droplets.
Polar body emission has Fertilization is suspected to take place been observed in very few sponges e. Caribbean population of Chondrilla nucula in There is a single TEM report in which puta- revealed that sperm release took place tive polar-bodies but predominantly con- more than 3 days before female spawning, taining yolk have been described in a ho- which consisted of mucous threads charged mosclerophorid demosponge Riesgo et al.
The process is condition also suggested from previous mediated by choanocytes, which phagocy- studies in Mediterranean populations Sid- tose the spermatozoa entering the chambers ri et al.
Experimental external ferti- in the inhalated water e. These choanocytes which gotes that developed until the late blastula do not digest the phagocytosed spermato- stage Maldonado, personal observations. During cell migration, the ready been discharged into the exhalant encysted spermatozoon, now referred to as aquiferous canals for imminent spawning. Spermiocyst transference similar to that observed in other lower in- may occur at early-stage oocytes or just im- vertebrates.
There are even cases in which mediately before their maturation, depend- the egg produces a fertilization-like mem- ing on the species. However, the mechanisms mechanism has not been properly docu- by which eggs that are shed within folli- mented in Demospongiae and Hexactinelli- cle-like envelopes or cases are fertilized re- da. Thus, serious doubts are raised as to the main unclear. We have found evidence in i. Both findings but rather a subtle asynchronous process suggest that the carrier-cell mechanism unnoticed by most divers.
The process of appears to operate in at least members of internal fertilization in brooding sponges this small demosponge order. An alterna- is only partially understood.
Internal fertil- tive mode of internal fertilization has been Figure 6 facing page. No- te the inset showing the striated substructure of yolk.
Riesgo postulated for carnivorous demosponges, proceed only after transference of the male such as Asbestopluma hypogea Vacelet, pronucleus. This appears to be the case in and Asbestopluma occidentalis Riesgo et al. In these sponges, la galangaui , and Hippospongia communis spermatophore-like spermatic cysts are re- Tuzet and Pavans de Ceccatty, Very leased from the sponges. The wall of these little information exists concerning fertiliza- cysts consists of a complex, cellular enve- tion success.
Fromont and Bergquist lope that also contains a peculiar type of estimated that fertilization success rate in protruding, hairpin-shaped spicules. In contrast, Petrosia ficiformis, a Med- jacent reproductive sponges. Experimental for subsequent fertilization. In sina aerophoba. In this species, the natural- some sponges, oocyte meiotic divisions ly released oocytes which were fertilized in Figure 7. Note that the 2 polar bodies pb are still visible at the egg surface.
Note that the envelope resists degradation for weeks after embryo hatching.
To our knowledge, the success of kes-Medrano and Leys, and larval internal fertilization has only been investi- stages Maldonado and Bergquist, ; gated in the demosponge C. Late blastulae experience extensive cel- rily on sexual reproduction, a few spong- lular reorganizations. These embryonic re- es largely rely on asexual reproduction or organizations have been regarded by some a combination of both processes e.
Asexual reproduction to that occurring during the embryogenesis typically occurs by budding, gemmulation, in other animal phyla e. Some other authors do not ac- which are cell masses growing at the exter- cept the occurrence of gastrulation in Por- nal surface of the body that subsequently ifera e. After tive explanation concerning how cell fates being dispersed by currents and waves for are assigned to form the larval and juvenile days to months, freed buds attach to the stages see Maldonado and Riesgo, , for bottom and give rise to a small sponge.
Embryogenesis gives rise to a The cytological composition of buds varies ciliate or unciliated, swimming or crawling largely between species. The most usual el- larval stage, except in those very few cas- ements in buds are a dense matrix of col- es of direct development. Up to eight basic lagen fibrils, totipotent archaeocytes, and larval types have been described in Porif- cells charged with large inclusions presum- era see table 1 for their taxonomic distri- ably for energy storage.
They may also con- bution: These types are determined habitats, although some marine species also according not only to differences in their fi- generate them see Fell, , and Simp- nal morphology but also to a distinct em- son, , for a review. Gemmules are dor- bryogenesis in each case.
Riesgo usually at the base of the sponge. Typical- bryo-bearing fragments also maximizes the ly, they are composed of a dense mass of chance that several distinct genotypes will totipotent archaeocytes and storage cells reach a new area, increasing the chance of thesocytes, nurse cells, etc surrounded establishing new populations.
Unlike buds, gemmules are Many aspects of sponge reproduction freed only after extensive tissue damage. For example, the They are thought to provide a means to as- process by which somatic cells become go- sure timely population restoration after ex- nial cells has never been investigated using tended severe mortality by transient unfa- modern techniques.
Likewise, the migra- vorable conditions drainage or freezing of tion mechanisms of mature spermatic cysts water bodies, extreme temperature events, and oocytes from the mesohyl to the exha- etc.
The relative resistance of gemmules to lant aquiferous canals for spawning remain both desiccation and the digestive process poorly understood. The processes deter- in the tract of large animals makes them mining and synchronizing spawning at the suitable for long-range dispersal via winds, population level has also been largely ne- birds, etc Fell, Many Accidental fragmentation of the sponge cytological aspects of fertilization need to body as a result of storms, waves, animal be clarified, particularly in the case of in- or human activity may also function as a ternal fertilization in Demospongiae and mechanism for asexual propagation.
This Hexactinellida, where the actual mecha- is due to the pluripotent capacity of many nisms for sperm transference to the oocytes sponge cell types and even small fragments have yet to be discovered. There is also a of the body that can contain cells enough to serious scarcity of studies concerning age, regenerate a new complete, small sponge. The contribution of sexual versus currents and storms Wulff, , In- asexual reproduction for long-term mainte- terestingly, fragments of some species have nance of natural populations has only been been demonstrated to contain developing roughly addressed so far and in very few embryos of sexual origin.
Even small frag- species. Therefore, much investigational ef- ments often carry the essentials cells for not fort needs to be devoted to the reproduc- only reorganizing as small sponges, but al- tive biology of Porifera in order to palliate so for nourishing the developing embryos this situation and reach the standard level which can successfully complete develop- of knowledge attained in other invertebrate ment and leave fragments as free-swim- groups. The dispersal of em- ty of Alberta for making material of A.
Colloques interna- search was supported by 2 grants from the tionaux du C. Diaz, J. Why do you think sponges might have an advantage when there are constantly high levels of nutrients available in the water?
Make a hypothesis! Station 2 discussion questions: How can studying sponge toxins help scientists in the field of human health? You may also take this time to discuss with classmates how sponges carry out life functions. Flag for inappropriate content. Related titles.
Endangered and threatened species: Northern aplomado falcons; nonessential experimental population establishment in New Mexico and Arizona. Jump to Page. Search inside document. Basics Porifera means pore-bearing. How can sponges threaten coral reef ecosystems?
What evolutionary advantages do toxins give to sponges? Would you classify sponges as living fossils? Why or why not? Station 3 activity: Sketch the sponge at this station label any parts that you can observe. Documents Similar To phylum porifera notes. Carley Rutledge. Jeremy Dupagan.
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