Phylum Cnidarians Flashcards
Also known as “True Jellyfish”
Class Scyphozoa
Also known as “Sea Wasps”
Class Cubozoa
Cnidarians have two different body plans which are?
Medusa and polyp
Body plan that resembles an upside-down cup or umbrella
Medusa
Tubular body plan with tentacle structures
Polyp
Cnidarians have __________ symmetry and are ____________
Radial symmetry, diploblastic
In Cnidarians, where is the mesoglea found?
In between the epidermis and the gastrodermis
True or False
All cnidarians have tentacles around the mouth and a single opening to the digestive system.
True
(If you got this wrong sumbong kita kay kuya fuki)
All cnidarians secrete __________, also called stinging cells.
Cnidae
Cnidae is secreted within cells called the ???
Cnidoblast
What is the most widespread and best-studied category of cnidae?
Nematocysts
Is a cluster of modified cilia that project from the cnidoblast and acts as a TRIGGER for the nematocysts.
Cnidocil
The force behind the discharge of the cnidae
Osmotic pressure
True or False
Cnidarians are primarily carnivores, but some soft coral species may feed on phytoplanktons.
True
What is the difference between Hexacorallina and Octocorallina?
Hexacorallina have 6 tentacles surrounding the mouth while, Octocorallina have 8.
Asexual reproduction via strobilation
Class Scyphozoa
“muscular cylinder” at the end of the mouth
Manubrium
Scyphozoans have a well-developed system of fluid-filled __________________ canal.
Gastrovascular
Are short nematocyst bearing tentacles lined around the gastric pouches that secretes digestive enzymes.
Gastric filaments
The enzymes partially digest the food and digestion is completed intracellularly through ___________________
Phagocytosis
Jellyfishes are equipped with a variety of sensory receptors.
- __________ - maintains the balance of the jellyfish
- __________ - optical receptors able to detect light
- __________ - detects tactile input.
- Statocysts
- Ocelli
- Sensory lappets
Statocysts and ocelli are contained in club-shaped structures called the ???
Rhopalia
True or False
Gas transfer occurs on the epidermal and gastrodermal surfaces.
True
Coiled thread-like stinger
Cnidocytes
Thought to be the juvenile of a jellyfish since it gradually changes its appearance becoming an adult scyphozoan
Ephyra
Cube-shaped medusa and rhopalia possess complex lensed eyes
Class Cubozoa
Species under cubozoa are called
Cubomedusae
True or False
Like scyphozoans, cubomedusae strobilate.
False, they DO NOT strobilate
Common species of cubomedusae
Chironex fleckeri
What class?
Polyp form is much more represented; gastroderm lacks nematocyst.
Class Hydrozoa
In Hydroids, where are the sense organs found?
At the base of the tentacles
One difference from scyphozoans is that hydroids possess a tissue called _________ that extends inwards from the edge of the bell.
Velum
Give one example of a hydrozoan
Hydra
Most hydrozoans are colonial in the polyp stage and gives rise to several polyps called ???
Zooids (also called ‘modules’)
Class Hydrozoa
The oral end of the polyp.
Hydranth
Class Hydrozoa
Each zooids share the gastrovascular cavity. They may be connected to one another or the substrate through the ____________.
Clue: it’s rootlike
Stolon
Class Hydrozoa
The stolon are usually encased in a transparent protective tube called the ???
Perisac
Class Hydrozoa
The “transparent protective tube” covering the “oral end of the polyp” is called the ???
Hydrotheca
Hydroid colonies may be _____________ or ______________, meaning that there are several structurally and functionally distinct zooids present in a single colony.
Dimorphic or polymorphic
Class Hydrozoa
Zooids/modules that are specialized in feeding
Gastrozooids
Class Hydrozoa
Zooids that are responsible for asexual repoduction by producing medusoid via budding.
Gonozooids
Class Hydrozoa
Finger-like structures or modules (zooids) that are specialized for defense.
Dactylozooids
Class Hydrozoa
Zooids that are densely armed with nematocysts but possess no mouth and is dependent on the other zooids for nutrition.
Dactylozooids
Class Hydroidolina possess three orders, but order _______________ best represents the polymorphism of the taxon.
Siphonophora
These organisms are free-floating hydrozoan colony in which the medusoid and polypoid morphs are observed simultaneously.
Order Siphonophora
Order Siphonophora
Propels the colony through jet propulsion by a structure called ???
Nectophore
Order Siphonophora
The medusa may also appear as leaf-like structures called ???
Bracts or phyllozooids
Order Siphonophora
Some species possess gas-filled structures that allow them to float called the ???
Pneumatophores
A small group of colonial hydrozoans that secrete calcareous skeletons resembling corals, however they are not true corals.
Order Hydrocorallina
Are spore forming parasites under phylum cnidaria
Class Myxozoa
Class Myxozoa
They possess distinctive organelles called ________________ and several of these are coiled together within the _________________
Polar filaments, polar capsules
They LOOK LIKE modified medusoids but live in polyp form.
BUT, they have no medusoid morph in ther life cycle
Class Staurozoans
Are called “mini harpoons” and also contains the toxin to be injected
Cnida
Types of Nematocysts
Penetrant, Volvent, Glutinant
Types of Nematocysts
Not only penetrates the victim, but also injects a poison.
Glutinant
Types of Nematocysts
Wraps around and ensnares a victim
Volvent
Scientific name of Moon Jellies
Aurelia aurita
Scientific name of Upside down jellyfish
Cassiopea sp.
Scientific name of Australian Box Jellyfish
Chironex fleckeri
Scientific name of Wind Sailor Jellyfish
Velella velella
