Phylum Cnidaria and Ctenophora A Radical Existence General Zoology BIO 120 Lecture NOVA Loudoun Campus Fall 2013 BIO 120 Objectives 7 Chapter 7 Objectives Please respond to the following questions in preparation for the lecture evaluation on this material 1 To which phylum do cnidarians belong What does Cnidaria mean What do Metazoa and Eumetazoa mean How many species of extant or living cnidarians are there 2 How many classes of cnidarians are there NOTE students should know Class Hydrozoa Class Scyphozoa Class Cubozoa and Class Anthozoa What do Hydrozoa Scyphozoa Cubozoa and Anthozoa mean 3 What are six characteristics of the cnidarians NOTE students should refer to pages 136 137 4 What are diploblastic and triploblastic animals What are the epidermis and gastrodermis and mesoglea What is the gastrovascular cavity or coelentreron What are cnidae What is the nerve net 5 What are the polypoid and medusoid forms NOTE students should refer to Figure 7 1 and be able to draw the dimorphic body forms of cnidarians Where are the basal disc mouth umbrella and tentacles 6 What are two characteristics of each cnidarian class 7 What is polymorphism and how is it expressed in hydroid colonies such as Obelia and Physalia What are the pharynx septal filaments siphonoglyphs or ciliates grooves and pedal disc found in sea anemones NOTE students should refer to Figure 7 11 8 What are the differences between scleractinian or stony corals and octocorallia or octocorals or horny corals What are zooxanthellae What is coral bleaching 9 What are cnidoblasts What are nematocytsts NOTE students should refer to Figure 7 19 and be able to draw an undischarged and discharged nematocyst 10 Is reproduction sexual or asexual or both within the cnidaria BIO 120 Objectives 7 Phylum Cnidaria and Ctenophora A Radical Existence 1 Cnidaria a Phylum Cnidaria b Cnidaria stinging nettle c Metazoa whole assemblage of animals large animals d Eumetazoa true animals e 9 000 extant species 2 Classes of Cnidaria a Hydrozoa serpent like b Scyphozoa cup c Cuboza box d Anthozoa flowering 3 Characteristics of Cnidarians a Radial symmetry b Diploblastic ectoderm and endoderm c Dimorphic i Polypoid ii Medusoid d Gastrovascular cavity incomplete gut e Cnidocytes f Nerve net g Alternation of generations 4 Terms a Diploblastic 2 true tissues b Triploblastic 3 true tissues c Epidermis outer layer d Gastrodermis inner layer e Mesoglea middle layer f Gastrovascular cavity sac like or branched cavity single opening only body cavity site of digestion g Cnidae stinging cells h Nerve net has some sensory structures 5 Cnidarian Anatomy a Polypoid sedentary b Medusoid mobile Phylum Cnidaria and Ctenophora A Radical Existence BIO 120 Objectives 7 6 Cnidarian Class Characteristics a Hydrozoa serpent like i Small ii Aquatic mostly marine iii Can live individually or in colonies iv Polymorphic b Scyphozoa cup i Medusa is dominant form ii Cellular mesoglea iii Gametes develop in gastrodermis iv Tentacles vary in length and number v Dioecious medusa vi Polypoids reproduce through budding vii Stobilia buds release as medusa i Medusa is dominant form ii Cellular mesoglea iii Gametes develop in gastrodermis iv Tentacles vary in length and number v Dioecious medusa vi Scyphistoma change to new medusa c Cuboza box d Anthozoa flowering i Can live individually or in colonies ii No medusa stage e Includes sea anemones corals sea fans and sea pansies 7 Cnidarian Terms a Polymorphism multiple regions of specialization on one organism b Pharynx muscle to move food for absorption c Septal filaments glandular ciliated band d Sphonoglyphs sweep food into mouth BIO 120 Objectives 7 Phylum Cnidaria and Ctenophora A Radical Existence 8 Corals a Stony corals vs horny corals i Stony calcium carbonate skeleton on bottom half of body typically reproduce asexually ii Octocoralia no calcium carbonate skeleton b Coral bleaching all living organisms have been stripped from coral c Zooxanthellae photosynthetic yellow brown unicellular algae in i Nematocyst type of cnidocyte harpoon like tube connected to toxic sacs for catching prey gastrodermal cells of cnidarians 9 Cnidocyte a Unique to cnidarians b Produced by cnidoblasts c Located throughout epidermis 10 Reproduction a Asexual b Sexual i Budding most common in polyp i Dioecious ii External fertilization iii May develop into polyp or medusa