Term
| What are the defining characteristics of the phylum echinodermata? |
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Definition
| Triploblastic bilateria, pentaradial symmetry (deuterostomes), enterocoelus, tripartite coelom, asteroid metamorphosis, central body, tube feet, generally slow locomotion, no distinct brain region, all marine, pedicellaria, ambulacral grooves? |
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Term
| What are dermal branchiae? |
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Definition
| Skin gills, projections through skeletal ossicles |
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Term
| Describe the ancestor of the echinodermata |
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Definition
| A benthic deposit feeder with bilateral symmetry |
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Term
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Definition
| Jaw-like projections on outside surface, help with parasites and in some species food collection |
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Term
| Name key features of the sea stars and their class |
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Definition
| Class=Asteroidea. Ambulacral grooves with tube feet on oral side, madreporite on aboral side, sensory tentacles on end of each arm with ocelli, large eversible cardiac stomach, hydroskeletal system with radial, lateral and ring canals. Ampullae involved in hydraulic movement of tube feet |
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Term
| Name the key features of brittle stars and their class |
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Definition
| Class=Opiuroidea. Arms sharply distinguished from central disk, lack pedicellariae and papulae, ambulacral grooves closed, covered by ossicles, visceral organs contained to disk, simple saccular stomach, light sensitive, no intestines or anus, madreporite oral, tube feet lack suckers, 5 moveable jaw plates, water circulates through genital slip across bursae for gas exchange, gonads release gametes into bursae and bursal slits |
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Term
| Name the key features of sea urchins and their class |
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Definition
| Class=Echinoidea. 5 ambulacrul grooves, test formed by dermal ossicles, long stiff moveable spines with ball and socket joint, a lot of sometimes venemous pedicellaria, long tube feet, Oral surface extends aborally up to the periproct, Aristotles lantern, simple nervous system, long coiled intestine, ciliated syphon |
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Term
| Name the key features of sea cucumbers and their class |
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Definition
| Class=Holothuroidea. Tube like shape, cloaca functions as water pump, secondarily bilateral, dermal ossicles much reduced, Longitudinal and circular muscles asynchronous locomotion, singular gonad, all benthic, expel part of viscera for defense |
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Term
| Name key features of sea Lilies and Feather stars |
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Definition
| Class=Crinoidea, sedentary, numerous in fossil record, dorsal mouth surrounded by arms and pinnules, Stem attached to substrate usually. |
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Term
| What is a tripartite coelom? |
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Definition
| Somatocoel, hydrocoel and exocoel |
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Term
| Describe asteroid metamorphosis in asteroidea |
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Definition
| The larva (bipinnaria) becomes brachiolaria which attaches to the substrate. This then metamorphoses into the adult sea star. |
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Term
| Sea stars can regenerate, true or false? |
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Definition
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Term
| Why are echinoderms senses underdeveloped? |
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Definition
| They have not undergone cephalisation |
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Term
| Why do echinoderms have spiny endoskeleton plates? (dermal ossicles) |
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Definition
| Because they have difficulty osmoregulating |
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Term
| What are ambulacral grooves in asteroidea? |
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Definition
| A groove or furrow bordered by large spines extending along the oral surface of each arm of sea stars, that contain two to four rows of small tubular projections called feet or podia |
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Term
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Definition
| Ampullae are bulb-shaped structures located above the tube feet of starfish and other echinoderms. Ampullae are an important part of the water vascular system of starfish, which is the responsible for the animal's locomotion. The only function of the ampullae is to store the water that enters the vascular system and send it to the minuscule tube feet, located in the ventral side of the starfish's arms |
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Term
| What is the function of the madreporite? |
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Definition
| To regulate pressures with valves in the radial canals |
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Term
| What is the function of aristotles lantern? |
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Definition
| It is a chewing mechanism in sea urchins (review picture) |
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Term
| Discuss cephalisation in echinodermata and its impacts |
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Definition
| No cephalisation, therefore under-developed senses and lack of bilateral symmetry |
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Term
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Definition
| Dermal Branchiae, or skin gills. Projections of the coelom that serve in respiration and waste removal |
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Term
| Describe how Asteroidea feeds and hint at it's feeding style |
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Definition
| Large eversible cardiac stomach (external digestion), predator/scavenger |
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Term
| In echinoidea, what does a long and coiled intestine imply? |
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Definition
| That they are herbivores (grazers) |
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Term
| What bypasses water around the stomach of Echinoids? |
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Definition
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Term
| Describe similarities in echinoidea and holothuroidea symmetry |
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Definition
| echinoids are pentaradial like all echinodermata, except for the sand dollar which has developed secondary bilateral symmetry, as have all the holothuroids |
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Term
Describe a common defense mechanism found in holothuroidea
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Definition
| Expel part of their viscera out of cloaca, some have cuvierian tubes which are sticky. |
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