FISH 310 Lecture Notes - Lecture 19: Asterozoa, Neontology, Madreporite
10 Jun 2018
School
Department
Course
Professor
Phylum Echinodermata
Characteristics of Echinodermata
Mutable Connective Tissue
Reversibly vary rigidity of dermis
§
Under nervous control
§
Tissue matrix stiffened by Ca2+
§
Feeding
§
Defense
§
Autonomy
Sever a portion of your body and leave it behind
□
§
Asexual Reproduction
Separate body segments can lead on separate lives
□
§
○
Water Vascular system (WVS)
Echinoderm hydraulic system with diverse functions
§
Podia (tube feet)
Ambulacral grooves/zones
□
Locomotion, gas exchange
□
Longitudinal muscles
□
§
○
Pentamerous radial symmetry (in adults)
○
-
Subphylums
Subphylum Asterozoa
Class Stelleroidea
Defining Characteristics
Arms/rays extend from a central disc
®
□
Subclasses
Subclass Asteroidea - sea stars
Characteristics
1600 extant taxa
}
Gonads & digestive tract extend into each
arm
Digestive glands, Radial Canal, Two
Gonads exist all together in each arm
–
}
WVS
Well developed
–
Used for:
Locomotion
w
Adhesion
w
Prey manipulation
w
Gas exchange
w
–
Process
Madreporite --> Stone
Canal --> Ring Canal --> Polian
vesicle and Tiedemann's
bodies --> Radial Canal -->
Ampullae --> Podia --> lined by
myoepithelium which are
ciliated and muscular
w
–
}
Madreporite
Is what emits water into the WVS
and lets it go out
–
On the aboral site of the sea star
–
Leads to the Stone Canal
–
}
◊
Reproduction
Asexual
May autotomize limbs and
regenerate
–
Usually must have a portion of
central disc
–
}
Sexual
Most are dioecious
–
Generally have 10 gonads (2 per arm)
–
Most broadcast spawn seasonally
–
One female may shed 2.5 million
eggs
–
Some cold water species are
brooding, direct developers
–
}
◊
Feeding
Wide variety of feeding styles
External digestion by everting
stomach
–
Ciliary-mucus feeding
–
Catch fish with pedicellaria
–
Dig through substrate for bivalves
–
May have general or specialized diet
–
}
◊
Defense
Run Away
}
Adhere to Substrate
}
Venom
}
Camouflage
}
Pedicellaria
}
SLIME!
}
◊
®
Subclass Ophiuroidea - brittle and basket stars
Characteristics
Bursae - invaginations on the oral surface
of the disc
10 bursae usually present
–
Extend into the coelomic cavity
–
Seawater circulated through the
bursae with cilia and muscular
contraction
–
Gas exchange, possibly waste
removal, some brood embryos in
bursae
–
}
Arms composed of calcareous vertebrae
}
◊
WVS
Similar to subclass Asteroidea except
Madreporite is positioned dorsally
–
May possess multiple madreporites
–
Ampullae are absent
–
Contraction of radial canal moves
podia
–
}
◊
Locomotion
Really fast for echinoderms
}
Tube feet rarely used to move, usually only
for food manipulation and burrowing
}
Brittle stars use long arms to move across
the substrate
}
Basket stars may brace themselves in
position with their arms
}
◊
Feeding and Digestion
Digestive system confined to central disc
}
Ophiuroids lack an anus
Secondarily lost one-way digestive
track
–
}
Many feeding strategies:
Carnivores
Ophioderma lassos small
crustaceans with arms and
transfers prey to mouth
w
If offered unlimited
crustaceans in a lab setting, it
will eat until the disc ruptures!
w
–
Scavengers
–
Deposit feeders
–
Suspension feeders
–
}
◊
Reproduction
Asexual
Clonal reproduction by fission of
central disc into two pieces
–
Larvae may cast off an arm, which
regenerates an entire body
–
}
◊
Ecology
Globally distributed
}
Common in Puget Sound
}
Very large biomass in deep, soft-bottomed
habitats
Can reach densities of 2000 per a
meters squared
–
}
◊
®
□
§
○
Subphylum Crinozoa
Class Crinoidea - sea lilies and feather stars
Characteristics:
Body held above substrate by stalk or grasping cirri
®
700 extant species
100 sea lilies (4 orders)
◊
600 feather stars (1 order)
◊
®
Very ancient class
Some extinct species were over 65 feet tall
◊
®
□
§
○
Subphylum Echinozoa
Class Echinoidea - sea urchins and sand dollars
§
Class Holothuroidea - sea cucumbers
§
○
-
Lecture 19: Echinodermata I
Friday, May 11, 2018
11:29 AM
Phylum Echinodermata
Characteristics of Echinodermata
Mutable Connective Tissue
Reversibly vary rigidity of dermis
§
Under nervous control
§
Tissue matrix stiffened by Ca2+
§
Feeding
§
Defense
§
Autonomy
Sever a portion of your body and leave it behind □
§
Asexual Reproduction
Separate body segments can lead on separate lives□
§
○
Water Vascular system (WVS)
Echinoderm hydraulic system with diverse functions
§
Podia (tube feet)
Ambulacral grooves/zones□
Locomotion, gas exchange□
Longitudinal muscles □
§
○
Pentamerous radial symmetry (in adults)
○
-
Subphylums
Subphylum Asterozoa
Class Stelleroidea
Defining Characteristics
Arms/rays extend from a central disc
®
□
Subclasses
Subclass Asteroidea - sea stars
Characteristics
1600 extant taxa
}
Gonads & digestive tract extend into each
arm
Digestive glands, Radial Canal, Two
Gonads exist all together in each arm
–
}
WVS
Well developed
–
Used for:
Locomotion
w
Adhesion
w
Prey manipulation
w
Gas exchange
w
–
Process
Madreporite --> Stone
Canal --> Ring Canal --> Polian
vesicle and Tiedemann's
bodies --> Radial Canal -->
Ampullae --> Podia --> lined by
myoepithelium which are
ciliated and muscular
w
–
}
Madreporite
Is what emits water into the WVS
and lets it go out
–
On the aboral site of the sea star
–
Leads to the Stone Canal
–
}
◊
Reproduction
Asexual
May autotomize limbs and
regenerate
–
Usually must have a portion of
central disc
–
}
Sexual
Most are dioecious
–
Generally have 10 gonads (2 per arm)
–
Most broadcast spawn seasonally
–
One female may shed 2.5 million
eggs
–
Some cold water species are
brooding, direct developers
–
}
◊
Feeding
Wide variety of feeding styles
External digestion by everting
stomach
–
Ciliary-mucus feeding
–
Catch fish with pedicellaria
–
Dig through substrate for bivalves
–
May have general or specialized diet
–
}
◊
Defense
Run Away
}
Adhere to Substrate
}
Venom
}
Camouflage
}
Pedicellaria
}
SLIME!
}
◊
®
Subclass Ophiuroidea - brittle and basket stars
Characteristics
Bursae - invaginations on the oral surface
of the disc
10 bursae usually present
–
Extend into the coelomic cavity
–
Seawater circulated through the
bursae with cilia and muscular
contraction
–
Gas exchange, possibly waste
removal, some brood embryos in
bursae
–
}
Arms composed of calcareous vertebrae
}
◊
WVS
Similar to subclass Asteroidea except
Madreporite is positioned dorsally
–
May possess multiple madreporites
–
Ampullae are absent
–
Contraction of radial canal moves
podia
–
}
◊
Locomotion
Really fast for echinoderms
}
Tube feet rarely used to move, usually only
for food manipulation and burrowing
}
Brittle stars use long arms to move across
the substrate
}
Basket stars may brace themselves in
position with their arms
}
◊
Feeding and Digestion
Digestive system confined to central disc
}
Ophiuroids lack an anus
Secondarily lost one-way digestive
track
–
}
Many feeding strategies:
Carnivores
Ophioderma lassos small
crustaceans with arms and
transfers prey to mouth
w
If offered unlimited
crustaceans in a lab setting, it
will eat until the disc ruptures!
w
–
Scavengers
–
Deposit feeders
–
Suspension feeders
–
}
◊
Reproduction
Asexual
Clonal reproduction by fission of
central disc into two pieces
–
Larvae may cast off an arm, which
regenerates an entire body
–
}
◊
Ecology
Globally distributed
}
Common in Puget Sound
}
Very large biomass in deep, soft-bottomed
habitats
Can reach densities of 2000 per a
meters squared
–
}
◊
®
□
§
○
Subphylum Crinozoa
Class Crinoidea - sea lilies and feather stars
Characteristics:
Body held above substrate by stalk or grasping cirri
®
700 extant species
100 sea lilies (4 orders)
◊
600 feather stars (1 order)
◊
®
Very ancient class
Some extinct species were over 65 feet tall
◊
®
□
§
○
Subphylum Echinozoa
Class Echinoidea - sea urchins and sand dollars
§
Class Holothuroidea - sea cucumbers
§
○
-
Lecture 19: Echinodermata I
Friday, May 11, 2018 11:29 AM
Document Summary
Sever a portion of your body and leave it behind. Separate body segments can lead on separate lives. Gonads & digestive tract extend into each arm. Canal --> ring canal --> polian vesicle and tiedemann"s bodies --> radial canal --> Ampullae --> podia --> lined by myoepithelium which are ciliated and muscular. Is what emits water into the wvs and lets it go out. On the aboral site of the sea star. Usually must have a portion of central disc. Some cold water species are brooding, direct developers. Bursae - invaginations on the oral surface of the disc. Seawater circulated through the bursae with cilia and muscular contraction. Gas exchange, possibly waste removal, some brood embryos in bursae. Tube feet rarely used to move, usually only for food manipulation and burrowing. Brittle stars use long arms to move across the substrate. Basket stars may brace themselves in position with their arms.
