Term
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Definition
| Urochordates and Cephalochordates |
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Term
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Definition
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Term
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Definition
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Term
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Definition
(vertebrates)
chordates with heads which have cartilaginous skulls and tooth-like structures composed of keratin |
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Term
| Synapomorphies of Craniata |
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Definition
cranium present
cartilage or bone or both are present
heart chambered
neural crests derived from vertebrate skeletal tissue |
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Term
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Definition
Aphelognathus
extinct chordates, earliest fishes
shape of conodont helps to assign relative ages of rocks
very few fully fossilized
-feeding basket: allows for feeding, tooth like projections that aid in filter feeding
active predators due to scarring from ground food and linear growth of mouth to body |
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Term
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Definition
| paraphyletic group of jawless fishes |
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Term
| Synapomorphies of Agnatha |
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Definition
no pelvic fins
no jaws, biting apparatus may be present
app. 530 Mya
no stomach |
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Term
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Definition
jawless fishes that are extinct
armored
heterocercal tail: lower part is longer |
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Term
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Definition
class Mixini
30-35 species
live deep scavengers
young develop directly from eggs
only marine- isoosmotic- no osmoregulation
feed on dead fish
rasping tongue |
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Term
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Definition
class Petromyzontida
about 40 species
osmoregulate- found in freshwater and ocean- parasitic
larval stage called ammocoete
ammocoete undergo metamorphosis
ammocoete filter feeds
feed on live fish |
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Term
| Agnatha- Gnathostomata Junction |
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Definition
synapomorphies
-jaws modified from gill
-paired limbs
vertebral centra usually present |
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Term
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Definition
synapomorphies:
head and shoulder girdles w/ dermal bony plates
five gill arches
both marine and freshwater |
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Term
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Definition
cartilaginous fishes
-cartilaginous skeleton, calcified but not ossified
-skull w/ no sutures
-teeth not fused to jaws: replaced serially
-internal fertilization w/claspers
-high blood concentration of urea
-embryos encapsulated |
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Term
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Definition
Chimaers- Ratfish
-single head
-gill cover over 4 gill openings
-head claspers |
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