Why do sponges classify spicules?
Spicules (or “spikes” for short) are structural elements found in most sponges. They provide structural support and deter predators. Large spicules that are visible to the naked eye are referred to as megascleres, while smaller, microscopic ones are termed microscleres.
What is the basis of classification of porifera based on?
Complete answer: Porifera is the phylum composed of the sponges. They lack true tissues, have no body symmetry, and are sessile. The classification of phylum Porifera is based upon the presence and composition of spicules.
What is the main basis of classification of sponges?
Although the majority of sponges live in marine habitats, one family, the Spongillidae, is found in fresh water. Calcarea, Hexactinellida, Demospongiae, and Homoscleromorpha make up the four classes of sponges; each type is classified based on the presence or composition of its spicules or spongin.
How do you classify porifera?
The phylum Porifera has four classes, namely the Calcarea, Demospongiae, Hexactinellida and Homoscleromorpha. Exclusively marine, calcareous sponges predominantly inhabit shallow tropical waters. They are often small and delicate, with thin coalescent tubes or a vase-like form.
What are 3 characteristics of porifera?
What are the characteristics of phylum Porifera?
- These are pore-bearing multicellular animals.
- The body has no organs.
- They exhibit holozoic nutrition.
- The body is radially symmetrical.
- They can regenerate their lost parts.
What are the 3 types of porifera?
Poriferans are commonly referred to as sponges. The approximately 5,000 living sponge species are classified in the phylum Porifera, which is composed of three distinct groups, the Hexactinellida (glass sponges), the Demospongia, and the Calcarea (calcareous sponges).
What is the classification of sycon?
Calcareous sponge
Which is the largest class in phylum porifera?
Demospongiae
How many classes are there in porifera?
four classes
How many types of porifera are there?
The phylum Porifera, which means “pore bearing,” consists of three classes of sponges, which together contain more than 5,000 species. While these sponges share many common characteristics, each class has distinctive traits that set it apart from the others.
What animals has no brain?
There is one organism that has no brain or nervous tissue of any kind: the sponge. Sponges are simple animals, surviving on the sea floor by taking nutrients into their porous bodies.