Radiate AnimalsI. Phylum CnidariaEvolved 700 mya; Pre-Cambrian.LocomotionFeeding & DigestionIII. Reproduction – Obelia life cycleCnidarians reproduce both asexually and sexually.Hydra Anatomy Portuguese Man O’ War:Class Anthozoa: Sea Anemones & CoralsBio Sci 100 1st Edition Lecture 7 Outline of Last Lecture I. EvolutionII. Grouping PoriferansIII. Phylum Porifera: DiversityIV. Phylum Porifera: EcologyOutline of Current Lecture I. Phylum CnidariaII. Sensory OrgansIII. Reproduction- Obelia life-cycleIV. Phylum Cnidaria: DiversityCurrent LectureRadiate AnimalsI. Phylum Cnidaria- Evolved 700 mya; Pre-Cambrian .- Approx. 9,000 species.- Widespread; mostly shallow, warm, marine habitats.- Cells are organized into tissues.- Diploblastic: having two true tissue layers.o (epidermis & gastrodermis)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Symmetry: Radial.- Sedentary or mobile as adults.Form & Function:- Gastrovascular Cavity- (GC): Inner body “sac” where food is taken in and waste is excreted. - Also used in locomotion.- Epidermis: outer layer of cells.- Gastrodermis: inner layer of cells with cilia lining the gastrovascular cavity (GC).- Mesoglea: gelatinous matrix between epidermis & gastrodermis hence the name "jelly".- Hydrostatic skeleton: water fills the GC and gives the animal rigidity (form).- No internal or external skeleton.II. Sensory OrgansNervous System:- Nerve cells are diffusely positioned throughout certain parts of the body/ body regions to make the nerve net.- Allows conduction of nervous impulses in both directions.- There is no grouping of nerve cells as in a central nervous system or brain.Locomotion- 'Jellyfish' movement occurs when water in the gastrovascular cavity is expelled during muscular contraction of the bell.- Coral and sea anemones are sedentary as adults.Feeding & Digestion- Cnidocytes: special cells along tentacles which contain nematocysts.- Nematocysts’ are organelles under high pressure that are triggered by contact releasing a barb that punctures the skin and releases venom.- There are over 20 types of nematocysts: 3 common examples include:- Stinging nematocysts: release venom into prey.- Recoil nematocysts: form a loop that retracts upon contact and “snares” part of prey.- Adhesion nematocysts: secrete an adhesive substance for grabbing prey.o Prey are drawn into the gastrovascular cavity where cells discharge enzymes; digestion isextracellular.III. Reproduction – Obelia life cycle- Cnidarians reproduce both asexually and sexually.1. Two adult medusa reproduce sexually.2. Creates a mobile larval form.3. Develops into a polyp.4. Polyp reproduces asexually by budding, and produces reproductive polyps.IV. Phylum Cnidaria: DiversityTwo basic body forms used for classification:- Polyp: sedentary, often colonial, mouth and tentacles are upturned.- Medusa: free swimming; mouth and tentacles are down-turned.Class Hydrozoa : - Live mostly in shallow marine (salt water) habitats.- Polyps are the dominant form.- Usually colonial and sedentary organisms.Hydra Anatomy Portuguese Man O’ War:Colony of polyps, or zooids integrated to act as oneindividual. MouthReproductive polyp Feeding PolypsGastrodermisGC Mesoglea Tentacles/DefensiveEpidermisBasal DiscClass Scyphozoa: Classic Jellyfish- Live in all marine waters: artic to tropical.- Surface and down to 3,000 meters.- Medusa is the dominant form.- Bells can reach 2 meters wide with 60-70 meter long tentacles.o Example: The Giant Jellyfish; a.k.a. lion’s mane jellyfish.o Up to 12,000 stinging tentacles!Class Cubozoa: Box Jellyfish- Marine (common in NE Australian coastal waters).- Medusa is the dominant form.- Tentacle(s) at each corner of the “box”.- Some are very deadly and can cause death in 2 minutes due to cardiac arrest.Class Anthozoa: Sea Anemones & Corals- All marine; shallow water.- Sedentary polyps (no medusa stage).- Solitary or colonial.- Anemones are carnivorous.- Often they are involved in symbiotic relationships with other organisms.- Examples of Symbiosis - Clownfish and Sea Anemone: commensalistic.o Stinging anemone provides shelter for clownfish.o Clownfish secretes mucous (specific to each anemone) that protects it.- Corals and zoozanthellae: mutualistico Coral provides shelter for the zooxanthellae.o Zoozanthellae are unicellular photosynthetic organisms provide coral with