BIO 044 - Module 8 Flashcards
Level of complexity: Tissue Level
Phylum CNIDARIA
Cells are specialized and organized enough to form tissues, but not
enough to form organs
Tissue level
Diploblastic (has 2 germ layers)
Phylum CNIDARIA
display dimorphism
Cnidarians
2 forms of cnidarians
-Polyp
-Medusa
Adapted to a sedentary or sessile life, remaining attached on surfaces
Polyp
They have tubular bodies with a mouth facing up and surrounded by tentacles
Polyp
Adapted for a floating or free-swimming life
Medusa
The mouth faced downward and the body is widened into a flattened bell or umbrella
shape, with the tentacles extending outward from the rim of the umbrella
Medusa
Important cells and structures in a cnidarian
-Cnidocytes
-Epitheliomuscular cells
-Nerve net
-Ocelli
Stinging cells
Cnidocytes
Cells that line the tentacles
and are used to hunt and
grasp prey, as well as for
defense
Cnidocytes
Performs muscular contractions and contributes to the
movement of the cnidarian
Epitheliomuscular cells
Found around the mouth as circular fibers (causes the mouth
opening to increase or decrease its diameter)
Epitheliomuscular cells
Found around the rest of the body as longitudinal fiber
(stretches or contracts the body)
Epitheliomuscular cells
Made up of nerve cells that create synaptic connections all over the body, allowing for the
cnidarian to react quickly to stimuli
Nerve net
No brain or central nervous system
Nerve net
“primitive eye”; a photosensitive sensitive organ that detects only light
Ocelli
Only found in a box jellyfishes
Ocelli
dioecious (separate males and females), and displays both asexual and sexual reproduction
Cnidarians
all ___ forms can reproduce sexually
medusa
____ forms are the only ones that
can reproduce asexually
polyp
The zygote will grow into a larva called ___ (which is ciliated and free-swimming)
Planula
When the planula settles on the sea floor, it will turn into the ___
polyp stage
s a type of transverse
fission (divides upwards instead of side to side)
strobilation
The immature/juvenile medusa are called ___
ephyra
Classifications of Phylum Cnidaria
Class HYDROZOA
Class SCYPHOZOA
Class CUBOZOA
Class ANTHOZOA
“Hydra” = a water serpent with many head on long necks (due to the appearance of the tentacles)
Class HYDROZOA
Can have just polyp forms, just medusa forms, or can have both forms
Class HYDROZOA
-If polyp, they are mostly colonial
-Mostly marine, some found in freshwater
Class HYDROZOA
- Mainly marine, some in
freshwater near the artic - Predominantly polyp form, but
can form small medusas
Obelia “sea fur”
- Solitary freshwate hydrozoan
- Has regenerative abilities and do
not appear to die of old age
(considered immortal) - Can freely move when hunting
Hydra “fresh-water polyp”
- Not a true medusa form, but
actually a colonial hydrozoan
(composed of 3 types of medusa
and 4 types of polypoids) - Freely floats on water
- Very painful stings
Physalia physalis
“Portuguese Man-o-War”
“skyphos” = cup
* The true jellyfishes
* Their bells/umbrellas display scalloping (the edges have many small curves)
* Tentacles are numerous
* Medusa form when mature, but has a polyp stage
Class SCYPHOZOA
- Found in warm coatal waters and
mangrove swamos - Reason why upside-down? They
have photosynthetic abilitys (so
face up to the sun) and is
symbiotic with dinoflagellates - Very mild sting
Cassiopeia
“Upside-down jelly”
- Largest and longest known
jellyfish in the world - Bell diameter: 2 meters
- Tentacle length: >100ft (longest
recorded is longer than blue whale) - Stings causes temporary pain but
not fatal
Cyanea capillata
“Lion’s mane jelly / Giant jelly”
- The most well-studies jellyfish
- Found in all waters, even in artic
- Has the ability to decrease in
size in unsuitable conditions
(smaller size requires less
energy
Aurelia
“Moon jelly”
“cubo” = cube, box
* The bell/umbrella is cube-shaped and does not have scalloping
* The tentacles are long and only found in the 4 corners of the cube
* Predominantly medusa form; polyp forms are unknown
* Verocious predators and fast swimmers
* Have ocelli (they are day hunters and use ocelli to detect light. At night, they sink to the bottom)
* Stings can be fatal
Class CUBOZOA
- “Anthos” = flower
- All polyps with a flower-like appearance
- No medusa stage
- All marine
- Can be solitary or colonial
Class ANTHOZOA
3 subclasses of Anthozoa
-Subclass HEXACORALLIA
-Subclass OCTOCORALLIA
-Subclass CERIANTIPATHARIA
▪ Display hexamerous symmetry (“hex” = 6 sides); they always display tubular tentacles
around the mouth
▪ Includes sea anemones and hard corals
Subclass HEXACORALLIA
▪ Display octomerous symmetry (“octo” = 8 sides); they always display featherlike tentacles
around the mouth
▪ Includes the sea fans, sea pens, soft and horny corals
Subclass OCTOCORALLIA
▪ Display numerous thin tubular tentacles
▪ Burrows under the sea floor surface and can build tubes made of sand
▪ Includes the tube anemones, and the black and thorny corals
Subclass CERIANTIPATHARIA
This cell lines the tentacles and is used to catch prey
Cnidocytes
This organelle has a thread with barbs and can deliver toxins to prey
Nematocyst
This process occurs when the polyp form starts producing medusas
Strobilation
This cnidarian class includes all the jellyfishes with scalloped bells
Scyphozoa
This sea anemone belongs to which subclass
Hexacorallia
