Chondrichthyes Flashcards
“What are Gnathostomes?
Jawed animals
“<b>What are 2 advantages of jaws?</b>”
Enhance foraging (biting off large chunks) & better manipulation
“<b>How doChondrichthyes squeeze gill arches together?</b>”
- bottom arch swivels to make chomping motion<br></br>- top arch remains attached to skull for stability
“<b>3 modes ofChondrichthyes reproduction?</b>”
oviparous, viviparous and ovoviviparous
“<b>Ovoviviparous<br></br></b><img></img><b><br></br></b>”
egg develop and hatch inside parent
“<b>Chondrichthyes are</b> monoceious/dioeceious <b>and reproduce via </b>internal/external<b> fertilizatoin?</b>”
Dioecious, Internal
“<b>What is the evolutionary purpose of a cartilaginous skeleton?</b>”
increase bouyancy
“<b>Subclass Elasmobranchii includes?</b>”
Sharks & Rays
“<b>DoSubclass Elasmobranchii have a notochord?</b>”
It is replaced by Vertebrae
“<b>What are the two stomach sections in Elasmobranchii?</b>”
cardiac and pyloric
“<b>What is the disadvantage of Elasmobranchii having a very short intestine?</b>”
limits nutrient absorbtion efficiency
“<b>Subclass Elasmobranchii have a Spiral valve use for?</b>”
large internal surface area<br></br>retain digestible material in ileum increase nutrient absorbtion
“<b>Elasmobranchii use a spiracle for</b>”
increase gas efficiency
“<b>Sharks swim to ___ the lungs,<br></br>While Rays _________</b>”
ventilate;<br></br><br></br>spiracles actively pump water over gills
“<b>Elasmobranchii have a 2 chambered heart. Divided into 1 ___ and 1 ____.</b>”
atrium<br></br>ventricle
“<b>The atrium and ventricle chambers in theElasmobranchiiheart is used for?</b>”
single circulation
“<b>Elasmobranchii have: (not well developed, excellent, limited)<br></br>___ hearing<br></br>___ vision<br></br>___ smell</b>”
not well developed, limited, excellent
“<b>What do the Ampullae of Lorenzinido?</b>”
sense electrical field of prey
“<b>Superorder Selachimorphabelongs to which Subclass?</b>”
Elasmobranchii
“<b>Superorder Selachimorpha include?</b>”
sharks
What does heterocercal mean?
“<b>Selachimorpha locomtion?</b>”
Paired fins for lift <br></br><br></br>Pectoral fins can’t swivel<br></br><br></br>fast speed but low maneuverability<br></br><br></br>Tail provides thrust and lift as shark moves through water<br></br><br></br>Head and fins flattened for lift during forward motion <br></br><br></br>Heavier than water: sink if they don’t continue swimming forward<br></br><br></br>Very fast sharks: modified tail fins for ↑ speed
“<b>Elasmobranchii have ___ bouyancy</b>”
negatively buoyant: sink if they stop swimming, heavoer than water<br></br><br></br>Expend more energy than if they were neutrally buoyant<br></br>
“<b>Placoid scales</b>”
Like small teeth and very tough <br></br><br></br>Flat rectangular base plate embedded in skin<br></br><br></br>Inner core of pulp composed of connective tissues, blood vessels and nerves <br></br><br></br>Pulp cavity treated by layer of odontoblast cells that secrete dentine <br></br><br></br>Covered with hard enamel outer layer<br></br><br></br>Secreted by cells in dermis <br></br><br></br>Pierce epidermis
Whale Sharks use 3 feeding methods:
Passive – swim slowly with open mouth, straining plankton <br></br><br></br>Vertical – float vertically, using suction to draw prey in <br></br><br></br>Active – suction filter-feed while swimming, drawing water into mouths at higher velocities: “ram-filter feeding”
“<b>What are claspers?</b>”
♂ has claspers: extensions of pelvic fins to transfer sperm to ♀
“<b>Do Selachimorpha have parental care?</b>”
No, take care of themselves from birth<br></br>
What are the 3 different types of shark egg development with examples?
“Viviparous: babies fed by a placenta that transfers nutrients from mother to young: give birth to live young. e.g., mako<br></br><br></br>Oviparous: deposit eggs that hatch later: ““mermaid’s purse“ - tough, leathery membrane; yolk feeds embryo. e.g., zebra shark <br></br><br></br>Ovoviviparous: eggs hatch internally but no placenta. e.g., cookiecutter shark”
Rays belong to the superorder __ and the order ___
Batioidea , Rajiformes
Rays
- DV flattened<br></br>- Benthic<br></br>Elarged winged pectoral fins<br></br>Move via wave like motion, lifiting and thrusting<br></br>respire: draw water into spiracles, force out gills,<br></br>5-6 gill slits on ventral surface<br></br>Tail, but the caudal fin reduced / absent<br></br>Small, blunt teeth in a plate used for grinding Dioecious: internal fertilization (♂ has claspers)
Subclass Holocephali: rat/rabbit fishes (ghost sharks) and elephant fishes
Very primitive: few surviving members in order Chimaeriformes <br></br><br></br>Elongated, soft bodies with a bulky head <br></br><br></br>One gill slit <br></br><br></br>Teeth fused to form plates <br></br><br></br>Lack placoid scales<br></br><br></br>Large pectoral fins and a long slender tail <br></br><br></br>No stomach <br></br><br></br>Benthic, often in very deep water <br></br><br></br>Move using sweeping movements of pectoral fins<br></br><br></br>Dorsal fin sometimes has a venomous erectile spine <br></br><br></br>Dioecious: internal fertilization, ♂ has claspers, ♀ oviparous
How did jaws progress?
modification of gill arches, arches move forward, arches squeeze together, bottom arch swivels, top arch fixed
“<b>What are 2 unique highly developed sensory organs in Chondrichthyes?</b>”
lateral lines & ampullary organs of Lorenzini
“<b>Holocephali have no ___ scales and no ____ for digestion.</b>”
placoid scales, stomach
“<b>Holocephali have a stomach. T/F?</b>”
False
“<b>Holocephali have no placoid scales. T/F?</b>”
True
What group of Chordates has a fusiform shape?
Superclass Selachimorpha (subclass Elasmobranchii)
Elasmobranchii have a large ______ and no ______ bladder.
oily liver, swim
What are placoid scales?
like tiny teeth secreted from dermis cells
What is subclass Elasmobranchii?
Sharks and Rays
The Ability to squeeze gill arches together developed
Jaws
Jaws move by bottom arch ____ and top arch ____ to skull
swivels, stays attached
Notochord replaced by vertebrae in which sublass of Chondrictheyes?
Elasmobranchii?
The purpose of cartilaginous skeleton to
increase buoyancy
Elasmobranchii stomach divided into 2 sections called:
cardiac and pyloric
What is an ileum?
The last part of the small intestine.
The Spiral valve ____ nutrient absorption
increases
Elasmobranchii have ___ to increase gas exhange
spiracles
The _____ extends from head down along side of body and ense pressure changes in water while the ______ are at the front of head used for electroreception
lateral lines
Ampullar of lorenzi
