Animals Taxonomy Flashcards
(233 cards)
What are the 5 subclasses of Cnidaria?
Hydrozoa
Scyphozoa
Cubozoa
Anthozoa
Staurozoa
What are the two morphological types of Cnidaria?
Polyp: hydroid, sedentary form
Medusa: jellyfish, floating form
What is the mesoglea?
The mesoglea is an extracellular matrix located between the epidermis and the gastrodermis of Cnidarians
What is the name of the particular cell type of Cnidarians and what’s their deal?
Cnidocytes: each of them is able to produce one of over 20 kinds of distinctive organelles called cnidae (e.g. Nematocysts: inject toxin for prey capture and defence)
How does the nematocyst in anthozoans discharge?
When stimulated the high internal osmotic pressure causes water to rush into the capsule, the operculum opens, and the rapidly increasing hydrostatic pressure forces the thread out with great force.
What does the venom of cnidarians contain?
enzymes (lipolytic and proteolytic proteins that catabolize prey tissue),
pore forming toxins and neurotoxins
Hydrozoa
mainly remain in polyp forms and create colonies. When present, medusae are small, and the mouth opens at the end of a manubrium
Scyphozoa
large jellyfish, velum absent, the manubrium usually forms 4 oral arms
Staurozoa
solitary polyps attached to the sea bottom, with the top resembling a medusa with eight
extensions
Cubozoa
the predominant form is medusoid, the bell is almost square with a tentacle or a group of
tentacles at each corner
Anthozoa
there is no medusa stage and may be solitary or colonial. This class contains 3 subclasses:
1. Hexacorallia: are the sea anemones and corals. Sea anemones can glide along a substrate, expand and stretch their tentacles and “swim” by rhythmical bending movements. Scleractinia (true or stony corals) live in calcareous cups in which polyps can retract.
2. Ceriantipatharia: are tube anemones (solitary and found in soft sediments) and thorny corals (are colonial and attached to a firm substratum)
3. Octocorallia: are soft and horny corals, such as sea fans, sea pens, sea pansies, and others
What are organs of equilibrium in invertebrates (e.g. cnidarians)?
statocysts
What are ocelli?
Light sensitive organs in Cnidaria
(not in Staurozoa)
(also in Platyhelminthes, Annelids, Molluscs, Echinodermata, Arthropoda)
In Scyphozoa and Cubozoa, there are different sensory organs called?
- Rhopalia
- Each rhopalium is club-shaped
- Each rhopalium contains a hollow statocyst for equilibrium
- In some species the rhopalia also bear ocelli
- In Cubozoa each rhopalium houses 6 eyes in addition to other sense organs (instead of ocelli)
How does the asexual reproduction in cnidarian occur?
budding
(hydrozoa,anthozoa)
How does the sexual reproduction in cnidarians occur?
By gametes and its present in all medusae and in some polyps
eggs and sperm released in water
In case of sexual reproduction: What is the larvae of cnidarians called?
planula
How do cnidarians feed?
They are all carnivorous and actively preying
What are zooxanthellea?
Mutualistic dinoflagellates of Cnidarians:
- photosynthesis and fixation of carbon dioxide –>provide for hosts
- recycle phosphor and nitrogen
- enhance ability of coral to deposit calcium carbonate
- require light
What are the two types of frameworks in Porifera?
Rigid: calcareous or siliceous structures called spicules
Fibrous: collagen fibrils present in the intercellular matrix. One form is called spongin.
What is the osculum in Porifera?
the point where the water exists the internal canals
What is the name of the typical cell form in Porifera and how are the three systems called according to the position of these cells?
Choanocytes:
1. Asconoid system: the choanocytes lie in a large chamber (Calcarea)
2. Syconoid system, the choanocytes lie in canals (Calcarea, some Hexactinellida)
3. Leuconoid system: the choanocytes lie in distinct chambers. This system has the highest proportion
of flagellated surface area for a given volume of cell tissue.
What do we mean with somatic embryogenesis in sponges?
Entire new sponges can develop from small fragments
How does the asexual reproduction occur in Porifera?
bud formation
External buds, after reaching a certain size, detach from the parent and float away to form new sponges, or they can remain to form colonies. There are also internal buds, called gemmules which remain dormant until the parent animal dies. This is a way of preserving the species during periods of freezing or drought.