1.
Phylum Cnidaria & Ctenophora Kingdom: Animalia Phylum Cnidaria Class Hydrozoa Class Scyphozoa Class Anthozoa Phylum Ctenophora

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Major Characteristics <ul><li>Presence of specialized tissues </li></ul><ul><li>Also called Coelenterates </li></ul><ul><li>Comprised of sea anemones, jellyfish, corals </li></ul><ul><li>Have radial symmetry </li></ul><ul><li>Two forms polyps and medusa </li></ul>

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Body Structure <ul><li>All have radial symmetry, where similar parts of the body are arranged and repeated around a central axis </li></ul>

4.
Radial vs. Bilateral Symmetry Diagram A

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Radial Symmetry

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Two Main Body Forms - Polyp <ul><li>A polyp is a sac like stage. </li></ul><ul><li>Sessile or non-motile </li></ul>

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Two Main Body Forms - Medusa <ul><li>A medusa is bell-like, which is similar to an upside down swimming polyp </li></ul><ul><li>Free floating or swimming </li></ul>

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Polyp vs. Medusa <ul><li>Some spend their life as both at some point or as one or the other the entire time </li></ul>Diagram B

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Polyp vs. Medusa Diagram D

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Three Basic Layers:

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Three Basic Layers <ul><li>Ectoderm/Epidermis – outer layer that contains the stinging cells </li></ul><ul><li>Endoderm/Gastrodermis – lines the gut </li></ul><ul><li>Mesoglea – Jelly like substance in between the Ectoderm and Endoderm which contains scattered cells and collagen fibers </li></ul>

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Exoskeleton <ul><li>Coral will create a calcium carbonate shell in which it will live </li></ul>

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Body Structure <ul><li>The mouth is located on the top of the polyp or underside of the medusa </li></ul><ul><li>It is the only opening on the organism so is also shares the function of being an anus </li></ul>Diagram E

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Body Structure Diagram F

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Tentacles <ul><li>Slender finger like structure used to capture and handle food </li></ul><ul><li>Location of nematocysts </li></ul>

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Nematocysts <ul><li>The main characteristic of Cnidaria is the presence of nematocysts </li></ul><ul><li>Stinging structures found on the tentacles </li></ul>

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Nematocysts <ul><li>Coiled – like stinger </li></ul><ul><li>Spring into the prey and releases toxin </li></ul><ul><li>Most not harmful to humans because they cannot penetrate skin </li></ul><ul><li>Some fatal </li></ul>

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Nervous System <ul><li>Main characteristic is the presence of a nerve net </li></ul><ul><li>Nerves cross over each other, at every connection, communication occurs </li></ul><ul><li>In humans millions cross over millions and no communication occurs </li></ul>

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Nerve Net Diagram C

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Digestive System <ul><li>All cnidarians are carnivorous </li></ul><ul><li>Paralyzed by the nematocysts </li></ul><ul><li>Enzymes in gastric cavity break down the food and nutrients are absorbed by cells in the endoderm </li></ul><ul><li>Wastes are sent out the mouth/anus </li></ul>

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Digestive System

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Reproductive <ul><li>Cnidarians have the ability to reproduce sexually and asexually </li></ul><ul><li>One method that is commonly seen is budding </li></ul>

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Class Anthozoa <ul><li>Largest group of Cnidarians </li></ul><ul><li>Stay in the polyp stage throughout life cycle </li></ul><ul><li>Solitary or colonial </li></ul><ul><li>Includes sea anemones </li></ul>

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Class Hydrozoa <ul><li>Can consist of just a polyp stage, just a medusa stage, or both </li></ul><ul><li>Can join together to form complex colonies such as the Portuguese Man-O-War, which develop floats </li></ul>FLOAT

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Class Scyphozoans <ul><li>Medusa is the dominant life stage </li></ul><ul><li>Swim with rhythmic contractions of the bell, though limited </li></ul><ul><li>Contain the most dangerous/fatal stings </li></ul>BELL

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Phylum Ctenophora <ul><li>Comb Jellies </li></ul><ul><li>Not a member of the Cnidarian Phylum even though they share similarities </li></ul>

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Cnidaria vs. Ctenophora <ul><li>Ctenophora </li></ul><ul><li>Have cilia at the base of the medusa to move </li></ul><ul><li>Engulf food </li></ul><ul><li>Do not have nematocysts </li></ul><ul><li>Have an additional layer between endo and ecto layers </li></ul><ul><li>Anal pore </li></ul>