Download Essentials of Human Anatomy & Physiology

The Craniates
Craniata
Subphylum Hyperotretihagfish
Subphylum Vertebrataostracoderms
lamprey
Gnasthostome fishes
Craniata
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Skull made of cartilage or fibrous tissue
Surrounds brain
Olfactory organs
Eyes
Inner ear
Subphylum Hyperoptreti
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Hagfish
Most primitive of all craniates
 Brain
 Bone
Both brain and bone key elements in evolution
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Subphylum Vertebrata
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The hyperoartia
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lamprey
Gnathostomata
Cartilaginous fishes
 Bony fishes
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Survey of Fishes
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Subphylum Hyperotreti- Hagfish
Subphylum VertebrataOstracoderms
 Lampreys
 Gnathostome Fishes
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Subphylum Hyperotreti
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Class Myxini
Hagfish Heads supported by cartilaginous bars
 Brains enclosed in fibrous sheath
 Lack vertebrae
 Retain notochord as axial support
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Four pairs of sensory tentacles surrounding mouths
 Ventrolateral slime glands
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Coldwater marine habitats
 Buried in sand and mud
 Feed on soft bodied invertebrates
 And scavenge on dying fish
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Subphylum Vertebrata
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Vertebrae that serve as a primary axial support
Include Jawless ostacoderms and Hyperoartia
(Lamprey)
Most part of a Superclass Gnathostomata
Include jawed fish and tetrapods
Ostracoderms
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Extinct agnathans
Bony armor
Bottom dwellers
Extracting annelids and other inverts from
sediment
Bony plates around mouth- jaw like structure
Hyperoartia
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Class Cephalaspidomorphi
Lamprey (agnathas)
 Marine and freshwater
 Prey on other fish
 Larvae filter feeders
 Mouth is suckerlike
 Epidermal teeth, rasping tongue
 Glands secrete anticoagulant and feed on blood
 External fertilization
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Gnathostomata
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Jaws evolved from anterior gill support arches that had
acquired a new role, being modified to pump water
over the gills by opening and closing the mouth more
effectively.
The mouth could then grow bigger and wider, making
it possible to capture small prey.
This close and open mechanism would with time
become stronger and tougher, being transformed into
real jaws.
Modified dermal bones on the surface of the skin
would migrate into the mouth and become primtive
teeth.
Paired appendages
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Increased activity
Increased stability
Lateral steering
Pectoral fins- usually just behind the head
Pelvic fins- ventral and more posteriorly
Modern bony fishes pelvic fins usually behind
the pectoral fins
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Ability to feed efficiently
Produced more offspring and exploit new habitat
Fostered adaptive radiation
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Cartilaginous fishes
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Class Chondrichthyes
Bony fish
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Class Osteichthyes
Class Chondrichthyes
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Sharks
Skates
Rays
Ratfishes
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Most carnivores or scavengers
Marine
Biting mouthparts
Paired appendages
Placoid scales
Cartilagious endoskeleton
Class Osteichthyes
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Bone in their skeleton
and/or scales,
bony operculum covering gill openings and
lungs or swim bladder.