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Since Cnideria have _____ surface-area-to-volume ratios, there are no special respiratory provisions and gas exchange is by _______
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H2O circulated within the ______________ helps distribute ___________ and ________
- gastrovascular chamber
- respiratory gases
- food.
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NH 3is lost by ________.
diffusion
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Fresh water types like Hydrao smoregulate but we do not know how. just saying
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Polyp movement just saying
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In polyps (e.g., Obelia& Hydra) the muscle processes of the ___________ cells are oriented to form a layer of _________ muscle
- epithelio-muscular
- longitudinal
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While the those of the nutritive muscle cells form a _________ layer.
circular
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The mesoglea acts as a __________ as does the water filled gastrovascularcavity.
hydroskeleton
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Think of the postural changes as acting on a cylider. When longitudal muscles contracct the cylinder gets shroter, when they expand it gets longer. When circular muscles contract it gets tighter, when they expand it gets wider
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Solitary polyps such as Hydra and anemones are capable of locomotion by “__________.”
somersaulting
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The _________ of many jellyfish confers neutral density on the animals.
mesoglea
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Should have slightly _________ density than seawater
higher
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Heavier anions such as __________ replaced by _________
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Such an animal does not have to ________ to stay up in the H2O column.
swim
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______ _________ is an example
Obelia medusa
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When Poly orchis stops jetting it ________
sinks
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The bell of Polyorchis ________.
floats
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The _________ and __________ are responsible for the greater density than seawater
-
This property allows it to fish with spread out tentacles. just saying
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Swimming in medusae?
Swimming is by jetting that involves alternate expansion and contraction of the bell.
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In Polyorchisand Obelia,cells of the ____________ epithelium lack muscle processes.
exumbrella
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The epitheliomuscular cells of the subumbrella surface are arranged such that along the radial canals muscle processes are arranged ________.
radially
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In each quadrant between radial canals the muscle processes are ______ and arranged _________.
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Contraction of the _________ muscles forces water out of the bell.
circular
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Elastic recoil of the mesoglea and probably limited contraction of the _______ muscles expand the bell.
radial
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NS control of swimming just saying
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Rhythmic swimming activity under control of ________.
nerve net.
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two __________ nerve rings found at the edge of the bell.
interconnected
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specifically _________ neurons
pace-maker
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Up to ________ groups of pacemaker neurons
eight
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What are statocysts
- statocyst is a balance organ present in some aquatic invertebrates (Cnidarian).
- It consists of a sac-like structure containing a mineralised mass (statolith) and numerous innervated sensory hairs (setae).
- The statolith's inertia causes it to push against the setae when the animal accelerates.
- Deflection of setae by the statolith in response to gravity activates neurons, providing feedback to the animal on change in orientation and allowing balance to be maintained.
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Obelia has which sensroy organ(s) __________________; Polyorchis """"" _________________
- statocysts
- photo receptors & statocysts
-
Polyorchis photoreceptor just saying
-
Cup shaped with two cell types
1.
2.
- 1. Sensory cells
- 2. Pigment cells
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Sensory cells have a ____________ structure
stereociliary
-
Hydrozoa just saying:
Integrated Taxonomic Information System (ITIS).
However we will follow the three groupings of–
Order Hydroida(not recognized by ITIS)–
Order Siphonophora(ITIS –Siphonophorae)–
Hydrocorals
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-
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___________ forms often referred as oceanic hydrozoans
Colonial
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_________organism (contrast with supraorganism)
Surperorganism
-
Many morphs –hydroid forms list the three of them and functions
- Gastrozooids– feeding and digestive functions
- Dactylozooids– protective & food capture
- Gonozooids– asexually producing medusae
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Medusoid morphs How many are there?
5 of them
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Whats the first Medusoid morph? Whats their morphology and function
- Nectophores–
- swimming individuals consisting of bell & propels the whole colony
-
Pneumatophores define them
Pneumatophores -gas-sac floats, medusa bell enclosing a bladder with secreted gas.
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Oleocysts–define
Oleocysts–medusa bell filled with oil
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Phyllozooids, or bracts define
Phyllozooids, or bracts –defensive forms with batteries of nematocysts but derived from medusae.
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Gonophores define
Gonophores –gonad-bearing individuals usually borne on gonozooids, rarely develop as free medusa.
-
-
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What three things did he label for hyrocorals
g
d
s
- gastrozooid
- dactylzooid
- skeleton
-
Scyphozoa just saying its time for these guys
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What ar these knwon as? Why?
“True” jellyfish wherein the acraspedote medusa is the dominant stage.
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Mesoglea is __________ and important in __________
-
Gastro vascularcavity highly ___________
compartmentalized
-
how many gastric puches does it have?
Stomach & four gastric pouches
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Septaledges in gastric pouches have ________ that carry batteries of __________.
-
More intricate system of canals. Direction of H2O flow:
Stomach → gastric pouches → adradialcanals → circular canal →interradial& periradialcanals →exhalent grooves on oral arms
-
fig 6.7 gastrovascular system of schyozoans
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Define rhopalia and associated structures
Rhopalia (singular: rhopalium) are small sensory structures of Scyphozoa (typical jellyfish) and Cubozoa (box jellies). In Aurelia they lie in marginal indententions around the bell and are flanked by rhopalial lappets. Specialized structures to sense light (ocelli) and perceive gravity (statoliths) are usually present. They also control the pace of swimming-muscle contraction.
-
-
-
Gonads in floor of gastric pouches. Sperm liberated directly. Ova held in stomach through fertilization and early cleavage of zygote. Note: strobilating scyphistoma= strobila
-
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The ________ with __________ symmetry is dominant stage in the life cycle.
-
Six to eight photoreceptors in each rhopalium. are any image forming?
At least two are image forming eyes
-
-
Exclusively ________ forms that tend to exhibit _______ symmetry
-
__________ cells arranged in muscle bands
Myoepithelial
-
Gastrovascularcavity divided by __________
mesenteries
-
Whats special about Anthozoas tentcles
Hollow tentacles
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Asexual reproduction by _________ or ________.
-
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