What are the characteristics of Hexactinellida?
Hexactinellida are characterized by having siliceous hexactine (six-pointed) spicules, making them the second class within the major sponge group Silicea. They also construct two different body plans: sycon and leucon.
What is unique about porifera Hexactinellida?
These are deep-sea sponges. They lack an epidermal covering, and their skeletons are composed of spicules of silica. The spicules, which often form a latticework, have six points or some multiple thereof. Glass sponges are pale in color and are cup- or basket-shaped.
What do Hexactinellida look like?
All glass sponges are upright, and possess specialized structures at their bases for holding fast to the ocean floor. Most appear outwardly to be radially symmetrical; they are typically cylindrical, but may also be cup-shaped, urn-shaped, or branching.
What are the characteristics of porifera?
Characteristic Features of Phylum Porifera
- They are generally marine aquatic organisms, with a few freshwater species.
- Their bodies are asymmetrical.
- Body shape can be cylindrical, vase-like, rounded or sac-like.
- They are diploblastic animals with two layers, the outer dermal layer and the inner gastral layer.
Where are Hexactinellida found?
Glass sponges in the class Hexactinellida are animals commonly found in the deep ocean. Their tissues contain glass-like structural particles, called spicules, that are made of silica (hence their name).
What family encompasses 90% of all sponges?
The approximately 8,550 living sponge species are scientifically classified in the phylum Porifera, which is comprised of four distinct classes: the Demospongiae (the most diverse, containing 90 percent of all living sponges), Hexactinellida (the rare glass sponges), Calcarea (calcareous sponges), and Homoscleromorpha …
What animal eats porifera?
A few species of fish, seaslugs and hawksbill turtles eat sponges, many sponge species contain toxic substances as well as sharp spicules to discourage predators.
What are the five 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 3 characteristics of sponges?
Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs. Some of them are radially symmetrical, but most are asymmetrical.
What are three types of Porifera?
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).
Are sponges male or female?
Sponges are generally hermaphroditic (that is, having male and female germ cells in one animal); however, some sponge species are sequential hermaphrodites (that is, having male and female germ cells that develop at different times in the same animal).
How does porifera look?
Adult sponges can be asymmetrical or radially symmetrical and come in a variety of sizes, colours, and shapes including tree-like, fan-shaped, cup shaped, tube shaped, ball shaped and shapeless.
What makes a hexactinellid different from other sponges?
The hexactinellids, or glass sponges, are characterized by siliceous spicules consisting of six rays intersecting at right angles, much like a toy jack. Hexactinellids are widely viewed as an early branch within the Porifera because there are major differences between extant hexactinellids and other sponges.
What are the characteristics of an adult Porifera?
Habit: They are solitary or colonial. Symmetry: Asymmetrical or radially symmetrical. Germ layer: Diploblastic animals. The adult body wall contains two layers, outer dermal layer and inner gastral layer. In between these two layers, there is a gelatinous and non-cellular mesoglea containing numerous free amoeboid cells.
What kind of environment does a hexactinellid live in?
Fossilized hexactinellids, however, seem to have been distributed across a wider range of environments (Van Soest, 2012). Many glass sponges have holdfasts of spicule mats or rope-like structures, which allow them to inhabit soft muddy substrates of deeper depths. Hexactinellida Diversity.
How many spicules are there in a hexactinellid?
The hexactinellids, or glass sponges, are characterized by siliceous spicules consisting of six rays intersecting at right angles, much like a toy jack.