The following points highlight the two main skeletal elements found in sponges. The types are: 1. Spongin 2. Spicules. Skeletal Element: Type # 1. Spongin: The spongin comprises of fibres of spongin and they resemble silk in appearance. These are proteinaceous secretion of the spongioblasts and form a network. In most cases, the spongin fibres are composed of protein, termed [...]
In this article we will discuss about the role and evolutionary significance of canal system in sponges. Role of Canal System: The canal system which draws water current inside the sponge's body and maintains a continuous uninterrupted flow of water, plays a vital role in the physiology of sponges, because it serves the various kinds of functions. (i) Nutrition: The [...]
The following points highlight the three main classes of Phylum Porifera. The three classes are: 1. Calcarea or Calcispongiae— (Calcareous Sponges) 2. Hexactinellida or Triaxonida or Hyalospongiae—(Glass Sponge) 3. Demospongiae. Phylum Porifera: Class # 1. Calcarea or Calcispongiae— (Calcareous Sponges): [Calcarea, L. Calcarious = limy, Calcispongiae, L. Calcis = genitive of calx = lime or chalk] Features: (i) Exclusively marine, [...]