Question

From Asconoid sponge: Leucosolenia, Syconoid sponge: Scypha, Leuconoid sponge, Gemmules (class Demospongiae), bath sponge, kitchen sponge, "boring" sponge Cliona (class Demospongiae), hexactinellid or "glass sponge" (cl Hexactinelid), Euplectella

Consider the differences between sponges of organization in terms of surface-to-volume relationships. Why are the larger forms more complicated?

Notice that not all sponges have spicules and not all sponges have spongin. Which sponge "architectures" are flexible and which are more rigid?

Notice that body size and shape are somewhat variable. Can you deduce which sponges are from wave-sheltered habitats and which are wave-exposed habitats?

Thank you!

Answer 1

Ans: Sponges are the most primitive animal group alive today and probably some of the first animals to appear on earth. abundant fossil record simplest animals closely related to the group of protozoan protists called the choanoflagellates whose cells very closely resemble the colar cells of sponges. Sponges with either an asconoid or syconoid water canal system generally have a radial symmetry. Sponges with a leuconoid water canal system have an asymmetric body shape, meaning that they lack a predictable symmetry growing to fit the space around them.

Sexual Reproduction involves the sperm from one sponge fertilizing the egg of a neighboring sponge (of the same species) resulting in an offspring possessing genes from both parents. Asexual reproduction by budding or fragmentation of the body wall, buds of cells break off and grow into new sponges genetically identical to the parent. Sponge body form more complex than asconiod pattern; has incurrent canals and side passages lined with choanocytes; single osculum.

There are three types of sponge architecture which includesasconoid (simplest), syconoid and leuconoid (most complex)

Asconoid sponge: Cell types and water flow through an asconoid sponge

Syconoid body form derived from smaller asconoids & overcame the surface area or volume constraints of the asconoid form. Syconoid body form increases surface area for filtering (shaded black above) by folding the asconoid surface now instead of a flagellated spongocoel (atrium) they have flagellated radial canals.

Leuconoid body form elaboration on the syconoid plan. further increase in surface area for filtering by subdividing the flagellated canals into flagellated chambers and more efficient water-pumping system.