Because Calcareous Sponges are filter feeders, their diet usually consists of particulates found in the water as well as many microscopic organic materials.From CreationWiki, the encyclopedia of creation science Pericharax heteroraphis; S. Petrobiona masselina; 4. In the case of budding, the sponges produce a cluster of cells known as a gemmule that is covered in a hard coating. This is intended as a first introduction to physiology for a college-level course. Calcareous Sponges can come in many different shapes such as a purse, vase, pear, or some other sort of cylindrical shape. (Illustration by Jonathan Higgins)This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. Heteractinida, characterized by a spiculate (consisting of six-rayed heteractinid octactines, poly-actines) and aspiculate calcitic skeleton, are now regarded as an extinct order of Calcarea, restricted to the Paleozoic. They are mostly colorless (whitish to beige), sometimes bright yellow (Leucetta chagosensis), dark greenish-brown (Pericharax heteroraphis), or fluorescent red/ orange (Leucetta microraphis, sometimes).Calcareous sponges have a skeleton that is made of calcium carbonate (calcite), composed of free diactines, tri-actines, tetracines, and/or polyactine spicules, to which a solid basal calcitic skeleton may be added, with either cemented basal spicules or which is fully embedded in an enveloping calcareous cement. Calcareous Sponge: Calcareous Sponges reproduce asexually by regeneration and through the process of budding. (Photo by Ron and Valerie Taylor. A framework for the book is homeostasis and how the body maintains balance within each system. Taxonomy: The class of calcareous sponges, Calcarea, includes 400, strictly marine species.
Soleneiscus radovani; S. Grantiopsis heroni; B. Sycon capricorn; l. Lemon-sponge (Leucetta chagosensis). It is now established that many of these forms actually belong to several groups of demo-sponges because of the possession of primary siliceous spicules, and only few to Calcarea (pharetronids and some sphinctozoans).
Reproduction.
Bruce Coleman, Inc. Reproduced by permission. )There is no known significance of calcareous sponges to humans.1. Calcareous Sponges live in shallow water and are exclusively found in marine environments.
Two competing hypotheses group a) Hexactinellida + Demospon-giae more closely together based on the possession of silicious spicules ("Silicea") in contrast to Calcarea ("Calcispongia") and b) Demospongiae more closely with Calcarea based on the possession of a cellular pinacoderm ("Cellularia"/"Pina-cophora") to the exclusion of Hexactinellida, which possess a cyncitial tissue structure ("Symplasma"). Three types of aquiferous system are realized in Calcarea: asconoid, all internal cavities are lined by choanocytes (flagellated cells) without folding of the choanoderm; syconoid, simple folding of the choanoderm; and leuconoid, choanocytes are arranged in discrete "choanocyte chambers. The majority of modern spiculate cal-careans would be found as dissociated spicules in the fossil record; there is only one record from the middle Jurassic at King's Sutton, Northamptonshire, where the form and arrangement of a calcareous sponge was preserved (Leucandra walfordi Hinde, 1893).Calcarea are regarded as one of four classes of the phylum Porifera (three extant [Demospongiae, Hexactinellida, Cal carea] and one fossil [Archaeocyatha]), distinctive in possessing a spicule skeleton composed exclusively of calcium carbonate and being the only poriferan taxon realizing all three stages of development of the aquiferous system (asconoid-syconoid-leuconoid). Calcareous Sponges lack the hollow cores that most other sponges have, but this makes the sponge stronger. Most Calcareous Sponges have a superficial radial symmetry. These were seen in Papua, New Guinea. Phylum Porifera Class Calcarea Number of families 22Marine sponges with calcareous skeletal elements (spicules)The fossil record of unambiguously identified Calcarea is relatively poor and fragmented.
Bruce Coleman, Inc. Reproduced by permission. There is still dispute about the true phy-logenetic relationships of the three extant sponge classes, including also the relationship of the class Calcarea to other (higher) diploblastic taxa like Ctenophora and Cnidaria. The eggs hatch to free swimming larvae which attach themselves to the bottom after a few days. (Photo by Bill Wood. Although thisconfirms that Calcarea are chemotaxonomically different from "Silicosponges" or "Silicea" (Demospongiae + Hexa-ctinellida), it does not necessarily imply sponge paraphyly.Number of classes and families: 1 class (Calcarea); 2 subclasses (Calcinea, Calcaronea); 5 orders (2 in Calcinea: Clathrinida, Murrayonida; 3 in Calcaronea: Leucosoleniida, Lithonida, Baeriida); 22 families; 75 genera; about 500 described species.Calcareous sponges are mostly small and inconspicious; they occur in a variety of forms, as single tubes, sometimes vase shaped, a mass of small tubes ("cormus"), a bushy arrangement of single tubes, or sometimes massive without any apparent symmetry. Therefore, it should be regarded as still contentious until further corroboratory data, such as a molecular multi-locus approach, is presented. Both proposals, however, assume poriferan monophyly. Both are a type of reproduction that results in a genetic clone. Reproduction may be both sexual and asexual, by budding.