Lecture 8 MARB 435Outline of Last Lecture1. Introduction of Cnidariaa. Cnidaria Diversity Examples2. General Morphology3. Cnidaria skin & cell layer (Structure and Function table)4. Cnidocytes5. Prey Capturing and Feeding of Cnidaria6. Photosynthetic symbionts in Cnidaria7. Cnidaria Reproduction8. Development and life cycle9. Cnidaria Taxonomy10. Medusozoa11. Class Scyphozoa12. Rhopalia13. Scyphoza14. Class Cubozoa (box jellies) & Box Jelly DiversityOutline of Current Lecture1. Stauromedusae2. Class Hyrdozoa3. Hydroids4. Hydroid Colonies5. Siponophores6. Hydrocorals7. Class Anthozoa8. Hexacoralia (Zoantheria)9. Sea Anemones10. Stony Corals (Scleractinia)11. Octocorals (Alcyonaira)12. Alyconarian Examples13. Gorgonians14. Introduction to Ctenophores15. Kleptocnida16. Ctenophore Tissue17. Metazoan Musculature18. Ctenophore Nervous Sytem19. Locomotion20. Gastrovascualr System21. FeedingCurrent LectureStauromedusaeThese are commonly known as ‘stalked jellies’ and can include Scyphozoa which sometimes are in a separate class. The medusa never breaks loose from the polyp. They have anadhesive organ which probably derived from Rhopalium and they function as a temporary attachment forsomersaulting.Class HyrodozaThis class is the only cnidarians class with freshwater species and they are mostly colonial. Either the medusa or the polyp is the dominant life form. The medusa often remains attached to the polyp andeffectively becomes its gonad. The class hydrozoa has three common species; hyroids, hydrocorals and siphonophores.HydroidsHyrdoids are a species that fall under the Class Hydrozoa. They’re mostly marine species but there are few freshwater representatives for example the Hydra. They’re colonial during the polyp stage called zooids and polymorphic. The medusa stage resembles scyphozoan medusa but there’s a velum present and it’s usually smaller. The velum is a soft palate that functions as amembranous structure usually covering another structure or opening.Hydroid ColoniesThere are two examples of hydroid colonies discussed; Podocoryne carnea and Obelia commissuralis. Podocoryne carnea is a athecate hydroid meaning they lack a theca which is a cell or shealth that encloses an organ or structure. Obelia commissuralis is a thecate hyrdoia meaning the theca is present.SiphonophoresThis species colnies indluce medusoid and polypoid zooids. Zooids are animals that can arse from budding or division. Some of these organisms have pneumatophores which are organisms that have gas filled sacs which assist in floating. An example of an pneumatophore would be a Portugese Man of War.HydrocoralsThese species secrete a calcareous skeleton and aren’t true corals. The true class of corals is Anthozoans but hydrocorals belong to the class Hydrozoa. Fire coral and rose coral are two examples of hydrocorals. They are very small marine water organisms.Class AnthozoaThis class contains the ‘true corals’. They contain only polyps and no medusa. The coelenterons (central gastrovascular cavity) is divided by vertical septa into radial compartments. The vertical septa are commonly called mesentaries. Also inside the pharynx areciliated grooves called the siphomoglyphs.Hexacoralia (Zoantheria)This subclass of Anthozoa includes 4000 species of sea anemones and corals. There symmetry is usually hexamerous. This means that the septa occurs in multiples of six. Something that most students should rememver is that anemones are solitary and corals are usually colonial.Sea AnemonesSea Anemones are solitary marine and freshwater organisms. They’re brightly colored and are known to be very diverse in the tropics. They attach to a substratum or borrowing. The substratum is either a layer of a rock or soil that is beneath the ground surface.Stony Corals (Scleractinia)There are approximately 360 species of Stony Corals that produce a carbonate exoskeleton. Some can be solitary but they’re more commonly seen in colonial form. There are various types of growth corals like brain coral, staghorn coral, table coral, starlet coral, mushroom coral, and finger coral.Octocorals (Alcyonaria)The corals have around 2000 species and are mostly colonial and tropical. Their septa and tentacles are present in multiples of eight. These type of coral use chemical defenses against their predators. Examples of Alcyonaria are blue coral, organ-pipe coral, sea feathers, sea pansies, and sea pens.GorgoniansThese are a part of the class Anthozoa. Gorgonians have an endoskeleton that is made ofgorgonin which is a highly cross linked of calcified collagen and proteins.Introduction to CtenophoresCtenophores are there on phylum of organisms. They are commonly known as comb jellies and are planktonic organism. They’r eexclusively marine animals with a estimate of 80 species. They can range in size from a few millimeters to 30 centimeters or more. One has been recorded to grow over 1.5 meters in length. They’re transparent and gelatinous organisms that move by utilizing their cilia. They are recorded to be voacious predators. Ctenes are locomotion organelles that are organized in comb rows.KleptocnidaeThese are a type of ctenophore and there’s one discussed in lecture; Haeckelia rubra. Haeckelia rubra doesn’t have collocytes. Kleptocnidae has cnidocytes that it gets from its prey, the hydromesusa Aegina citrea (kleptocnidae).Ctenophore TissueCtenophores has three tissue layers the bilayered epirdermis, gastrodermis, and mesoglea. The bilayered epidermis is composed of two layers. The outer layer is multiciliated cells, mucus-secreting cells, ocllocytes and sensory cells. The inner layer has a myoepithelial cells and a nerve net. The gastrodermis is composed of nutritive cells and photocytes which are bioluminescent. The mesoglea is compose of an extracellular matrix (with ocllagen), ameboid cells, nerve cells and myocytes.Metazoan MusclatureMetazoa musculature is complex that has actin and myosin filaments. The metazoan musculature’s main function is to produce muscle contractions. The actin and myosin filaments slide past each other to make these contractions. There are two types of musculature, epithilealmusculature and non-epitheleal musculature. The differences is one contains epithelial cells while the other doesn’t and that non-epitheleal musclulature has myocytes inside them. Mycocytes are simple muscle cells.Ctenophore Nervous SystemCtenophore’s nervous system has three main components, an epidermal