Sponge FAQs:

Q: Were sponges first to branch off the evolutionary tree from the common ancestor of all animals?

A: Yes, and making them the sister group of all other animals.

Q: Are sponges not monophyletic?

A: Yes, because the last common ancestor of all sponges would also be a direct ancestor of the Eumetazoa, which are not sponges.

Q: Are sponges fundamentally sessile animals?

A: Yes, and some marine and freshwater species can move across the sea bed at speeds of 1–4 mm per day, as a result of amoeba-like movements of pinacocytes and other cells.

Q: Are sponges absent from the fossil record until the Cambrian?

A: Yes.

Q: Are sponges similar to "type IV" collagen?

A: Yes.

Q: Are sponges sessile aquatic animals?

A: Yes.

Q: Are sponges hermaphrodites , although sponges have no gonads?

A: Yes, Sperm are produced by choanocytes or entire choanocyte chambers that sink into the mesohyl and form spermatic cysts while eggs are formed by transformation of archeocytes, or of choanocytes in some species.

Q: Were sponges widely regarded as a monophyletic group?

A: Yes, and all of them having descended from a common ancestor that was itself a sponge, and as the "sister-group" to all other metazoans , which themselves form a monophyletic group.

Q: Are sponges closest to the ancestors of all Metazoa?

A: Yes, and of all multi-celled animals including both sponges and more complex groups.

Q: Are sponges fused, for example if there is a large but still unseparated bud, these contraction waves slowly become coordinated in both of the "Siamese twins"?

A: Yes, The coordinating mechanism is unknown, but may involve chemicals similar to neurotransmitters.

Q: Are sponges more abundant but less diverse in temperate waters than in tropical waters?

A: Yes, and possibly because organisms that prey on sponges are more abundant in tropical waters.

Q: Are sponges a tube or vase shape known as "asconoid"?

A: Yes, but this severely limits the size of the animal.

Q: Are sponges similar to other animals in that they are multicellular?

A: Yes, and heterotrophic, lack cell walls and produce sperm cells.

Q: Are sponges between glass sponges and the rest?

A: Yes, and that Eumetazoa are more closely related to calcareous sponges, those with calcium carbonate spicules, than to other types of sponge.

Q: Are sponges drastically simplified forms?

A: Yes.

Q: Are sponges worldwide in their distribution?

A: Yes, and living in a wide range of ocean habitats, from the polar regions to the tropics.

Q: Are sponges the next closest?

A: Yes, the other demosponges are evolutionary "aunts" of these groups; and the chancelloriids, bag-like animals whose fossils are found in Cambrian rocks, may be sponges.

Q: Were sponges traditionally distributed in three classes: calcareous sponges , glass sponges and demosponges?

A: Yes, However, studies have shown that the Homoscleromorpha, a group thought to belong to the Demospongiae, is actually phylogenetically well separated.

Q: Are sponges demosponges?

A: Yes, and fossilized remains of this type are less common than those of other types because their skeletons are composed of relatively soft spongin that does not fossilize well.

Q: Are sponges more closely related to each other than either is to calcareous sponges?

A: Yes, and which in turn are more closely related to Eumetazoa.

Q: Are sponges similar to the leuconid structure?

A: Yes.

Q: Are sponges usually found on firm surfaces such as rocks?

A: Yes, but some sponges can attach themselves to soft sediment by means of a root-like base.

Q: Are sponges in fact a monophyletic group?

A: Yes, and with the cnidarians form the sister group to the bilaterians.

Q: Are sponges sister-group to all other multicellular animals?

A: Yes, and ctenophores emerge as the second-earliest branching animal lineage, and placozoans emerge as the third animal lineage, followed by cnidarians sister-group to bilaterians.

Q: Are sponges the most common in polar waters and in the depths of temperate and tropical seas?

A: Yes, as their very porous construction enables them to extract food from these resource-poor waters with the minimum of effort.

Q: Are sponges the sister group to the rest of animals?

A: Yes.

Q: Were sponges assigned to a separate subkingdom?

A: Yes, and Parazoa , separate from the Eumetazoa which formed the rest of the kingdom Animalia.

Q: Are sponges abundant and diverse in shallower non-polar waters?

A: Yes.

Q: Are sponges the sister group to the rest of animals?

A: Yes.

Q: Are sponges known for regenerating from fragments that are broken off?

A: Yes, although this only works if the fragments include the right types of cells.

Q: Are sponges noted for their wide range of collaborations with other organisms?

A: Yes.