Cnidaria Diversity

Question 1

Cnidarian reproduction occurs both….

Answer 1

sexually and asexually

Question 2

Cnidarians are gonochoristic, meaning…

Answer 2

they have opposite sexes

Question 3

Cnidarian dispersal occurs via …

Answer 3

• gametes, larvae, or medusae

Question 4

What are the two Cnidarian subphyla? How do they differ?

Answer 4

• Medusozoa and Anthozoa
• Medusozoa have linear mitochondrial DNA

Question 5

Most species of cnidarians go through both a _____ and _____ phase

Answer 5

MEDUSA AND POLYP PHASE

Question 6

What are the 2 classes in the subphylum anthozoa

Answer 6

• hexacorallia
• octocorallia

Question 7

What are the 4 classes in the medusozoa subphylum

Answer 7

• staurozoa
• hydrozoa
• scyphozoa
• cubozoa

Question 8

Class scyphozoa is ____ dominant

Answer 8

MEDUSA

Question 9

What does digestion and circulation look like in class scyphozoa?

Answer 9

• 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

Question 10

What is the Rhopalia?

Answer 10

• the location of sensory organs in scyphozoa cnidarians

Question 11

What do the statocyst, ocellus, and rhopalial lappets all function as in scyphozoa

Answer 11

• They are all sensory organs
• Statocyst: orient gravity
• ocellus: eyes
• Rhopalial lappets: touch

Question 12

What is a genet? a Ramet?

Answer 12

Genet: genetically distinct individual

Ramet: Clone, produced asexually

Question 13

What is strobilation?

Answer 13

a unique for of asexual reproduction for scyphozoa polyps

Question 14

What is the point of having sexual and asexual reproduction?

Answer 14

• 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.

Question 15

What are some of the key characteristics of Class cubozoa?

Answer 15

• ‘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

Question 16

What as some key characteristics on class hydrozoa?

Answer 16

• 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

Question 17

Why do some hydrozoans live in colonial forms?

Answer 17

• thought to be a survival strategy

Question 18

What class is NOT part of the anthozoa and medusozoa sub phylums

Answer 18

Myxozoa

Question 19

What is the basic anatomy of colonial hydrozoans?

Answer 19

• shared gastrovascular cavity
• have stolons, structures that connect individual ramets, which are protected by the perisarc

Question 20

What are hydrozoans polymorphic colonies? the 3 kinds?

Answer 20

• where zooids (ramets) of many different shapes/kinds work together.
• gastrozooids (feeders)
• gonozooids (reproducing)
• dactylozooids (for defense)

Question 21

What are myxozoa?

Answer 21

• phylum cnidaria, not part of the other sub phylums
• extracellular parasites of aquatic annelids and freshwater bryozoans

Question 22

What are the 5 defining characteristics of subphylum anthozoa?

Answer 22

1. no medusa stage (all polyps
2. No operculum or snidocil
   - circular mitochondrial DNA
3. siphonoglyph
4. mesenteries/septa partition coelenteron