What is the anatomy of a sponge?

Anatomy: The body of a sponge has two outer layers separated by an acellular (having no cells) gel layer called the mesohyl (also called the mesenchyme). In the gel layer are either spicules (supportive needles made of calcium carbonate) or spongin fibers (a flexible skeletal material made from protein).

What are the 3 body types for Porifera?

Body types: Sponges have three body types: asconoid, syconoid, and leuconoid.

What are 3 types of spicules in Porifera?

Based on the number of axis present in the rays spicules may be of three types: monoaxon, triaxon and polyaxon. Monaxon: These spicules grow along a single axis. These may be straight needle-like or rod-like or may be curved. Their ends may be pointed, knobbed or hooked.

What is respiration in sponges?

The respiratory system of a sponge is based on the process of diffusion. It is controlled by the ostia and special cells called choanocytes that help move water around the sponge’s body, using channels in their mesohyl tissue.

What kind of body does a rotifer have?

Anatomy of a bdelloid rotifer Rotifers have bilateral symmetry and a variety of different shapes. The body of a rotifer is divided into a head, trunk, and foot, and is typically somewhat cylindrical.

Why are rotifers important to the zooplankton?

Rotifers are an important part of the freshwater zooplankton, being a major foodsource and with many species also contributing to the decomposition of soil organic matter. Most species of the rotifers are cosmopolitan, but there are also some endemic species, like Cephalodella vittata to Lake Baikal.

What are the characteristics of the phylum Rotifera?

The phylum rotifera has been subdivided into three classes by Ruppert and Barnes (1994). i. Elongated body with a long neck. ii. Presence of a much reduced corona.

Is the foot of a rotifer a syncytial cell?

Both the foot and the toes may be reduced in several genera and species. The rotifer integument is syncytial, which means that the epidermal cells are not separated by cell membranes. An outer cuticle, which is present in most other invertebrates, is lacking in rotifers, and instead they have an intracellular filamentous lamina.