Quiz 2 - Phylum Cnidaria Flashcards
What do interstitial cells (totipotent cells) do in cnidaria
Make gametes and cnidocytes
What are the receptor cells in cnidaria?
Sensory cilium
Make a loose nerve net
Epithilio-muscular cells function as skin and muscle in cnidaria. What do they contain that are longitudinal in the epidermis but circular in the gastrodermis?
Myofibrils
What class are the true jellyfish
Scyphozoa
What have a thick mesoglea, found mostly in the medusa stage, are active carnivores with a well developped gastrovascular cavity
Scyphozoa
What is the manubrium in scyphozoa?
Underside of the bell, stalk like structure that hangs down the centre, with the mouth at is tip
There are usually four arms attached to the manubrium
Explain the aurelia life cycle of class scyphozoa
Planula - scyphisotoma - stobilation - ephyra - medusa
Explain in detail the different stages of scyphozoa life cycle
Planula - fertilized eggs w cilia, that turn into a polyp, free swimming larva
Scyphistoma - asexul budding of the polyp, turns into a segmenting polyp
Strobilation - tentacles reabsorbed, body starts to narrow
Ephyra - baby medusa stage, start breaking off
Medusa - adult jellies, sexual
What class are the box jellies
Cubozoa
Whats a defining feature of cubozoa
4 tentacles from 4 corners
No stobilation!!!
What is different from class scyphozoa to class cubozoa in terms of their life cycles
Cubozoa- no strobilation
Mate by mono strobilation
What is the life cycle of cubozoa
Mate
Planula
Settle and form polyps
Medusa
What are the stalked jellyfish
Class staurozoa
What class has an attached medusa stage and no alteration of generation (aka direct development)?
Staurozoa
What class is found in mostly the polyp stage?
Hydrozoa
What is the life cycle of hydrozoa
Mate
Planula
Polyp
Asexual reproduction of polyp
What class is the sea anemones and the corals
Anthozoans
What class has no medusa stage and a divided gastrovascular cavity (coelentron)
Anthozoa - corals and anemones
What class are good circular and longitudinal muscles
Anthozoa
What is a scyphisotoma in scyphozoa
Segmented polyp after the planula stage, when the start budding
What are the 5 main classes of jelly / cnidaira
Scyphozoa Cubozoa Staurozoa Hydrozoa Anthozoa
What are the soft corals classified under?
Subclass alcyonaria / octocorallia
What are some characteristics of the octocorallia / alcyonaria
8 part symmetry
Soft coral / more mesoglea
Deep sea corals
What is subclass zoantharia / hexacorallia
6 way symmetry anemones and hard corals
What class are the hard corals
Hexacorallia
What are the reef building corals (hermatypic) classified under
Hexacorallia/ zoantharia
What is the life cycle of a coral
Hermaphroditism Sexual or asexual Broadcast spawning - corals release gametes simultaneously Make planula - then polyp Budding from oral disc / at base
Where does coral budding happen
At the oral disc / at the base
What is group myxozoa
Slime or mucus animals
Parasites of fish / invertebrates
What are the two morphological forms of myxozoa
Motile worm and spore forming sacs
Do myxozoams have a gut or a nervous system
Nope
Bilateral symmetry is the presence of anterior posterior and dorsal ventral - but cnidarians show oral - aboral with their mouth (blastopore) on one end. How are they bilateral animals?
Shows bilateral expression during embryogenesis
Also, they have bilateral hox genes even though they lack morphological A-P axis
What are the 2 major evolution events of cnidarians
Make axial properties
Form multilayered animals through gastrolation - endoderm and ectoderm
