Class Anthozoa
Organisms of this class lack a medusa. The polyps can be either colonial or solitary. These are all marine organisms, they consist of corals and anemones. are radially symmetrical externally, and are have biradial symmetry on the inside.
Distinguishing features of Anthozoan polyps:
Sea anemones are an example of solitary anthozoans. They can attach to solid substrates, soft substrates, and live in symbiotic relationships. Through the use of a pedal disk it is able to attach itself to its substrate. They also have an oral disk; which contains the mouth and solid, oral tentacles. A siphonoglyph (ciliated tract) attached to one or both ends ofthe mouth allows water into the gastrovascular activity to maintain its hydro-static skeleton.
Mesenteries are arranged in pairs. Mesenteries can attach themselves to the body wall on the outside margin and pharynx on the inside margins. Others attach to the body wall, allowing them to be free along the inner margin. Mesenteries close to theoral disk can allow water to circulate between compartments set off by mesenteries. Free lower edges of mesenteries create mesenterial filaments; which bear cnidocytes, cilia that help circulate water, gland cells that secrete digestive enzymes, and cells used to take in products of digestion. At the end of mesenterial filamentst are threadlike acontia, acontia have cnidocytes. When an anemone feels threatened it can push out acontia through small openings in the body wall, the acontia is able to subdue prey. Mesenteries have longitudinal muscle bands, which can be contracted whenever the anemone feels threatened, this causes water to escape from the gastrovascular cavity. Also, during this action the oral end of the column folds over the oral disk, causing the anemone to appear as if it had collapsed. The hydro-static skeleton can retake its form by taking in water.
Anemones are able to move if they crawl on their sides, use their pedal disk to glide, or walk on their tentacles. Anemones are able to float by holding gas bubbles in the folds of their pedal disks. Anemones eat invertebrates and fish. They are able to capture their prey using their tentacles, then they are able to drag their food towards their mouth. radial muscle fibers in mesenteries open the mouth. Anemones are able to reproduce asexually and sexually. During asexual reproduction a piece of the pedal disk can break away can create a new organism, this process is called pedal laceration. Also, one individual can be divided into two through longitudinal or transverse fission. Anemones can be monoecious or dioecious. In monoecious organisms, protandry is where male gametes mature faster than female gametes so self-fertilization doesn't occur. Fertilization can occur externally or in the gastrovascular cavity.
Distinguishing features of Anthozoan polyps:
- Mouth leads to pharynx , is an invagination of body wall that leads to the gastrovascular cavity.
- Mesenteries, which are membranes, with cnidocytes and gonads on their free edges divide the gastrovascular cavity.
- Mesoglea has amoeboid cells.
Sea anemones are an example of solitary anthozoans. They can attach to solid substrates, soft substrates, and live in symbiotic relationships. Through the use of a pedal disk it is able to attach itself to its substrate. They also have an oral disk; which contains the mouth and solid, oral tentacles. A siphonoglyph (ciliated tract) attached to one or both ends ofthe mouth allows water into the gastrovascular activity to maintain its hydro-static skeleton.
Mesenteries are arranged in pairs. Mesenteries can attach themselves to the body wall on the outside margin and pharynx on the inside margins. Others attach to the body wall, allowing them to be free along the inner margin. Mesenteries close to theoral disk can allow water to circulate between compartments set off by mesenteries. Free lower edges of mesenteries create mesenterial filaments; which bear cnidocytes, cilia that help circulate water, gland cells that secrete digestive enzymes, and cells used to take in products of digestion. At the end of mesenterial filamentst are threadlike acontia, acontia have cnidocytes. When an anemone feels threatened it can push out acontia through small openings in the body wall, the acontia is able to subdue prey. Mesenteries have longitudinal muscle bands, which can be contracted whenever the anemone feels threatened, this causes water to escape from the gastrovascular cavity. Also, during this action the oral end of the column folds over the oral disk, causing the anemone to appear as if it had collapsed. The hydro-static skeleton can retake its form by taking in water.
Anemones are able to move if they crawl on their sides, use their pedal disk to glide, or walk on their tentacles. Anemones are able to float by holding gas bubbles in the folds of their pedal disks. Anemones eat invertebrates and fish. They are able to capture their prey using their tentacles, then they are able to drag their food towards their mouth. radial muscle fibers in mesenteries open the mouth. Anemones are able to reproduce asexually and sexually. During asexual reproduction a piece of the pedal disk can break away can create a new organism, this process is called pedal laceration. Also, one individual can be divided into two through longitudinal or transverse fission. Anemones can be monoecious or dioecious. In monoecious organisms, protandry is where male gametes mature faster than female gametes so self-fertilization doesn't occur. Fertilization can occur externally or in the gastrovascular cavity.
The other anthozoans are corals. They can form coral reefs. When threatened polyps retract into their exoskeleton. Through asexual budding corals can produce more members for the colony. Stony corals have large amounts of zooxanthellae, algae in which corals have symbiotic relationships with. Photosynthesis by dinoflagellate zooxanthellae provides the corals with organic carbon. Corals provide nitrogen and phosphorus for the algae through metabolism.