Lecture 8 MARB 435 Outline of Last Lecture 1 Introduction of Cnidaria a Cnidaria Diversity Examples 2 General Morphology 3 Cnidaria skin cell layer Structure and Function table 4 Cnidocytes 5 Prey Capturing and Feeding of Cnidaria 6 Photosynthetic symbionts in Cnidaria 7 Cnidaria Reproduction 8 Development and life cycle 9 Cnidaria Taxonomy 10 Medusozoa 11 Class Scyphozoa 12 Rhopalia 13 Scyphoza 14 Class Cubozoa box jellies Box Jelly Diversity Outline of Current Lecture 1 Stauromedusae 2 Class Hyrdozoa 3 Hydroids 4 Hydroid Colonies 5 Siponophores 6 Hydrocorals 7 Class Anthozoa 8 Hexacoralia Zoantheria 9 Sea Anemones 10 Stony Corals Scleractinia 11 Octocorals Alcyonaira 12 Alyconarian Examples 13 Gorgonians 14 Introduction to Ctenophores 15 Kleptocnida 16 Ctenophore Tissue 17 Metazoan Musculature 18 Ctenophore Nervous Sytem 19 Locomotion 20 Gastrovascualr System 21 Feeding Current Lecture Stauromedusae These 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 an adhesive organ which probably derived from Rhopalium and they function as a temporary attachment forsomersaulting Class Hyrodoza This 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 Hydroids Hyrdoids 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 a membranous structure usually covering another structure or opening Hydroid Colonies There 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 Siphonophores This 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 Hydrocorals These 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 Anthozoa This 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 are ciliated 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 Anemones Sea 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 Gorgonians These are a part of the class Anthozoa Gorgonians have an endoskeleton that is made of gorgonin which is a highly cross linked of calcified collagen and proteins Introduction to Ctenophores Ctenophores 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 Kleptocnidae These 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 Tissue Ctenophores 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 Musclature Metazoa 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 epithileal musculature 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 System Ctenophore s nervous system has three main components an epidermal nervous net mesoglea nerve cells and the apical organ The epidermal nervous net is concentrated near the comb rows