Download - Chordates 1 - University of Rio all 4 chordate characteristics in adult • common name: lancelets •
Kingdom Animals
• Eukaryotic
• Multicellular - Many cell types
• Heterotrophic
• Feed by ingestion
• No cell walls
• Diploid life cycle
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Phylogenetic Tree
Radial Symmetry2 tissues
Bilateral Symmetry3 tissues
Deuterostome
Deuterostome
Protostome
no tissues
Molt
Don’t molt
Lopho-phore
Porifera
Cnidaria
Ctenophora
Lophophorates
Rotifer
Platyhelminthes
MolluscsAnnelids
Nematodes
Arthropods
EchinodermsChordates
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Acoelomate
Gut
Pseudocoelomate
Pseudocoel
Gut
Eucoelomate
Gut
coelom
Platyhelminthes
NematodaRotifera
AnnelidaArthropodaTardigradaMolllusca
EchinodermataChordata
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Phylum Echinodermata
• starfish and relatives
• larva - bilateral symmetry
• adults - radial symmetry
• endoskeleton - numerous plates
• spines
• unique water vascular system
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Starfish Video fromwww.arkive.org
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Water Vascular System
tube feet
ring canal
radial canals
Sieve plate
See handout
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Arm Cross Section
skeletalplates
epidermis
spines
pincers
gonads
digestive gland
tube feet
See handout
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Phylum Chordata
• notochord - dorsal stiffening rod
• dorsal hollow nerve cord
• pharyngeal gill pouches
• postanal tail
Possess at some point in life cycle
3 Subphyla
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Subphylum Cephalochordata
• all 4 chordate characteristics in adult
• common name: lancelets
• <10 cm
• burrow in mud
• filter-feed
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Subphylum Urochordata
• tunicates - tough casing
• sea squirts
• incurrent & excurrent siphons
• mostly sessile filter-feeders
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Diversity of Tunicates
Bluebell Tunicate Purple Tunicate
Free-Swimming Tunicate
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Subphylum Vertebrata
• all 4 chordate features in embryos
• notochord replaced by vertebrae
• skull
• endoskeleton of bone or cartilage
• large coelom
• 7 classes
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Evolutionary Tree
ancestortunicate larva
vertebrae
jaws
bones
lungs
limbs
amnionic egg Mammals
Reptiles & Birds
Amphibians
Lobe-finned fish
Ray-finned fish
Cartilaginous fish
Jawless fish
Tunicates
Lancelets
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Class Agnatha
• jawless fish
• cartilaginous skeleton
• notochord persists
• no scales
• some filter feeders
• some parasites
lamprey
hagfish
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Class Chondrichthyes
• “cartilaginous fish”
• cartilaginous skeleton
• jaws
• dermal denticles (scales)
• some predators
• some filter-feeders
shark
rays and skates
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Class Osteichthyes• bony fish
• jaws
• scales
• gills covered by operculum
• most ray-finned (thin fins supported by thin bony rays)
• many swim bladder (buoyancy)
• very diverse
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Lobe-Finned Fishes• small subgroup of bony fishes
• have fleshy fins supported by bones
Coelacanths Lungfish
deep-sea freshwater (Africa, S. America)have gills & lungs
survive dry spells by burrowing/reducing metabolism
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Class Amphibians
• “both land and water”
• eggs and larva aquatic, gills
• adult terrestrial, simple lungs
• most tetrapods (4-legged)
• thin, non-scaly skin
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Salamanders and Newts
• elongated body
• 4 equal legs
• tail
Red-spotted newt
Spotted Salamander
Mudpuppy
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