Term
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Definition
Jawless fishes
"name" means not valid group
Evolved ~500 mya
Similar to living species |
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Term
Shared Lack of Characters Lamprey/Hagfish
(5) |
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Definition
Lack jaws
No paired fins (pelvic/pectoral)
Gametes released into coelom
Lack scales
Lack stomach |
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Term
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Definition
Hagfishes
All marine
~ 75 species
Benthic, deep water
Burrow into sediment |
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Term
Myxiniformes Derived Characters
(3) |
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Definition
Vertebrae (vertebral elements)
Cranium (protein fibrous/little shelf under brain)
1 pr semicircular canals |
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Term
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Definition
Covered eyes under skin (photoreceptors)
Barbels (chemoreceptors)
Tongue
Gill pouches (many)
1-15 external gill opening
1 caudal fin |
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Term
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Definition
2 plates w/ 2 rows of keratin "teeth"
Hinged like a book |
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Term
Myxiniformes Osmoconformer
(2) |
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Definition
Body fluid concentration matches outside
Rare among vertebrates |
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Term
Myxiniformes Slime Glands
(3) |
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Definition
~ 200 along body
Secrete massive amounts of mucus
Deters predators |
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Term
Myxiniformes Diet and Feeding
(2) |
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Definition
Mostly scavengers
Predators on benthic inverts |
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Term
Myxiniformes Knotting Behavior
(3) |
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Definition
Braces for tearing flesh
Removes mucus
Escape from predators |
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Term
Myxiniformes Reproduction and Life Cycle
(3) |
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Definition
100:1 Female to male sex ratio
Mating unknown
Females lay 20-30 eggs (case, protein based, w/hooks/ attach to substrate/ offspring show direct development) |
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Term
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Definition
Lampreys
~ 40 species northern temperate
20 species: sea lampreys (anadromous)
20 species: book lampreys (freshwater streams) |
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Term
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Definition
Hatched in freshwater
Mature and go to ocean
Breed in freshwater |
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Term
Petromyzontiformes Derived Characters
(8) |
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Definition
2 pairs semicircular canals
Pineal organ (day length/adjust biological rhythm)
Electroreceptors
Vertebrae (rudimentary/arculia)
Lateral line system (lost in hagfishes)
Well developed eyes
2 dorsal fins
Keratinized "teeth" on buccal funnel and tongue |
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Term
Petromyzontiformes Osmoregulators
(2) |
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Definition
Regulate concentration of body fluids
Chloride cells in gills (can move salt ions against the concentration gradient) |
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Term
Petromyzontiformes Tidal Ventilation
(2) |
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Definition
H2O in and out gill openings
Feed and respire at same time |
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Term
LAMPREY
Diet and Feeding (Adults)
(6) |
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Definition
Some brook species non-feeding
Most parasitic on fish
Feed on fluids
Produce anticoagulant
Continuous feeding
Human parasites |
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Term
Reproduction (Sea Lampreys)
(4) |
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Definition
Spawn in gravel-bedded streams
Builds nest out of ring of stones
Lays 1,000 of eggs
Breed once and die (semelparous) |
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Term
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Definition
Filter feeders
3-7 years
Metamorphosis late summer
Adults go to ocean by spring |
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Term
Brook Lamprey Larval Stage
(2) |
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Definition
Stay in same stream born in
Usually breed and die within 6 months of metamorphosis |
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Term
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Definition
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Term
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Definition
Fossils from 500-200 mya
4 cm long, marine fishes
Derived characters: conodont elements, mineralized tooth-like structures, 1st mineralized tissue |
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Term
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Definition
Not monophyletic group
Poorly known
Fossils from 480-360 mya
Freshwater and marine
10-50 cm long
Derived Characters: dermal bone (plates or shell), cerebellum (motor activity), paired pectoral fins (some) |
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Term
Why are jaws important?
(7) |
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Definition
Feeding
Manipulating prey
New food resources
Biting, chewing, tearing
Building nests
Courtship and mating
Tool use and manipulation |
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Term
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Definition
Derived from branchial (gill) arches
1st pr: mandibular arches (mandibular and palatoquadrate cartilages) |
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Term
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Definition
Proto-jaws lacked teeth
Mallat's hypothesis |
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Term
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Definition
Evolved 1st for improved gill ventilation
Combined w/ hypobranchial muscles (operate jaws and pharynx) |
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Term
Water flow and mandibular arches
(4) |
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Definition
Opens oral cavity and pharynx
Increase in volume creates suction to draw water in
Closes mouth: forces H2O through gills (buccal pumping)
Increases efficiency of gas exchange |
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Term
Gnathostome: Derived Characters
(8) |
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Definition
Jaws
Increase hypobranchial muscles
3 pairs of semicircular canals
2 nostrils and 2 olfactory bulbs in brain
2 sets of paired fins help w/ steering and breaks (pectoral and pelvic)
Stomach: digests larger food items
Gonadal ducts: cloaca
Vertebrae advancements: Centra (surrounds notochord), ribs (support trunk musculature) |
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Term
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Definition
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Term
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Definition
Armored fishes
Fossils from 440-360 mya
Primarily marine
Benthic predators
Primitive tooth plates (extensions of jaws) |
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Term
| Placoderms Derived Characters |
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Definition
Dermal shield w/ head joint (anterior 1/3 of body)
Head lifted while feeding
Dermal bone= semidentine (unique mineralized tissue) |
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