Cnidaria Diversity Flashcards
Cnidarian reproduction occurs both….
sexually and asexually
Cnidarians are gonochoristic, meaning…
they have opposite sexes
Cnidarian dispersal occurs via …
- gametes, larvae, or medusae
What are the two Cnidarian subphyla? How do they differ?
- Medusozoa and Anthozoa
- Medusozoa have linear mitochondrial DNA
Most species of cnidarians go through both a _____ and _____ phase
MEDUSA AND POLYP PHASE
What are the 2 classes in the subphylum anthozoa
- hexacorallia
- octocorallia
What are the 4 classes in the medusozoa subphylum
- staurozoa
- hydrozoa
- scyphozoa
- cubozoa
Class scyphozoa is ____ dominant
MEDUSA
What does digestion and circulation look like in class scyphozoa?
- gastrovascular canals take food to the entirety of the body, and collect waste products
- this also serves as a circulatory system
- additionally, there is no respiration system, relies on diffusion through all surface of the body
What is the Rhopalia?
- the location of sensory organs in scyphozoa cnidarians
What do the statocyst, ocellus, and rhopalial lappets all function as in scyphozoa
- They are all sensory organs
- Statocyst: orient gravity
- ocellus: eyes
- Rhopalial lappets: touch
What is a genet? a Ramet?
Genet: genetically distinct individual
Ramet: Clone, produced asexually
What is strobilation?
a unique for of asexual reproduction for scyphozoa polyps
What is the point of having sexual and asexual reproduction?
- if you can produce very good offspring by sexual means, it makes sense to want to duplicate that offspring
- good offspring determined if they landed in a good spot (little competition, access to resources). If they are in a good spot, they will reproduce asexually.
What are some of the key characteristics of Class cubozoa?
- ‘box-like’ medusa
- very efficient swimmers , as their bell margins are more restricted so water comes out fast and provides more thrust
- they are highly venomous
- complex eyes with multiple lens
What as some key characteristics on class hydrozoa?
- The polyp is more prominent in the lifecycle
- Medusa’s have velum: sheet of tissue that constricts the bell opening, which provides a greater thrust
- Ramets and sessile polyps may live in colonial forms
Why do some hydrozoans live in colonial forms?
- thought to be a survival strategy
What class is NOT part of the anthozoa and medusozoa sub phylums
Myxozoa
What is the basic anatomy of colonial hydrozoans?
- shared gastrovascular cavity
- have stolons, structures that connect individual ramets, which are protected by the perisarc
What are hydrozoans polymorphic colonies? the 3 kinds?
- where zooids (ramets) of many different shapes/kinds work together.
- gastrozooids (feeders)
- gonozooids (reproducing)
- dactylozooids (for defense)
What are myxozoa?
- phylum cnidaria, not part of the other sub phylums
- extracellular parasites of aquatic annelids and freshwater bryozoans
What are the 5 defining characteristics of subphylum anthozoa?
- no medusa stage (all polyps
- No operculum or snidocil
- circular mitochondrial DNA
- siphonoglyph
- mesenteries/septa partition coelenteron
