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Primitive craniate characteristics?
- · Partial cranium
- · No vertebrae
- · Cartilagenous skeleton
- · Weak circulatory system with 3 accessory hearts
- · Scavengers
- · Produce slime as defense mechanism
- · Four pairs of sensory tentacles surround mouth
- · Jawless; tongue has tooth-like rasps
- · Adults can change sex from year to year
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What is the most primitive craniate?
Hagfishes
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All remaining chordates are and they possess what?
craniates (possess a skull)
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What are some characteristics of Cephalochordata?
- · Marine; invertebrates
- · Larvae and adults exhibit all 4 chordata features
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What are Cephalochordata?
(lancelets)
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What are some characteristics of Urochordatel?
- · Marine; invertebrates
- · Larvae exhibit all 4 chordate features; adults retain pharyngeal gill slits
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What are Urochordatel?
(sea squirts, ascidians)
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Phylum Chordata includes 3 subphyla?
- · Urochordata
- · Cephalochordate
- · Vertebrata
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Chordates possess 4 structures at some point in life cycle. What are those 4 points in life?
- · Pharyngeal slits (ancestrial trait)
- · Dorsal, hollow nerve cord (becomes spine and brain)
- · Postanal tail
- · Notochord
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What are some characteristics of Hemichordata?
- · Bilateral symmetry; ciliated larva
- · 3 part body plan (proboscis, color, and trunk)
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What are Hemichordata?
acorn worm, pterobranch
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What are some characteristics of Holothuroidea?
- Lack arms and spines
- Reduced endoskeleton
- 5 rows of tube feet
- Tube feet around mouth modified as feeding tentacles; suspension feeders
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What are Holothuroidea?
sea cucumbers
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What are some characteristics of Crinoidea?
- · Feathered arms surrounding upward pointing mouth
- · Suspension feeders
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What are Crinoidea?
(sea lilies, feather stars)
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What are some characteristics of Ophiurolodea?
- Long flexible arms
- Distinct central disk
- Nocturnal scavengers
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What are Echinoidea?
sand dollars, sea biscuits, sea urchins
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What are some characteristics of Echinoidea?
- · Roughly spherical or disk-shaped
- · No arms
- · Covered with spines (attached to endoskeleton via ball and socket joint)
- · 5 rows of tube feet, enabling slow movement
- · Mouth ringed by complex, jaw like structure –eat algae and seaweed
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What are Ophiurolodea?
brittle stars
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What are some characteristics of Asteroidea?
- · Star shaped body; multiple arms radiate from central disk
- · Mouth and tube feet on oral surface
- · Two stomachs – one everts to digest prey
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What are Asteroidea?
sea stars
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What are the five classes of enchinodermata?
- Asteroidea
- Ophiurolodea
- Echinoidea
- Crinoidea
- Holothuroidea
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Enchinodermata characteristics?
- · Marine
- · Larvae bilaterally symmetrical and ciliated
- · Adult has radial symmetry (most)
- · No head; oral – aboral body surfaces
- · Internal skeleton of fused calconeous plates; covered by skin and some muscle.
- · Unique water vascular system with tube feet
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Vertebrates?
vertebral column, ventral hear, anterior skull, large brain
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Chordates?
notochord dorsal hollow nerve chord, post anal tail
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What are Chordata?
sea squirts, lancelets, vertebrates
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What are Hemichordata?
acorn worms, pterobranchs
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What are Echinodermata?
sea stars, sea urchins
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What are the three major phyla of deuterostomes?
- Echinodermata
- Hemichordata
- Chordata
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Deuterostomes characteristics?
- · Triploblastic
- · Bilateral symmetry
- · Embryonic blastopore becomes anus
- · Exhibit radial cleavage
- · Endoskeleton
- · Coelom develops from mesodermal outpocketings of the archenteron
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