Lecture 4 Pt. 2

Question 1

Major body plans (6 learned)

Answer 1

1.) Cydippida
2.) Beroida
3.) Platcytenida
4.) Cestida
5.) Lobata
6.) Thallasocalycida

Question 2

Cydippida

Answer 2

• Long tentacles
• Spherical body
• Most early larva have have cydippied bodies
• Likely polyphyletic

Question 3

Beroida

Answer 3

• Large, sealable mouth
• Cylindrical body
• No tentacles or sheaths

Question 4

Platyctenida

Answer 4

• Benthic
• Comb rows reduced
• Mostly flattened
• Mouth is semi-everted
• Internal fertilisation

Question 5

Cestida

Answer 5

-Belt-like body

Question 6

Lobata

Answer 6

• Large, muscular oral lobes

Question 7

Thallasocalycida

Answer 7

• Medusa-like bell shape

Question 8

Biradial symmetry

Answer 8

• Divide along axis
• Rotate 180
• Allows broad interactions with some directed movement

Question 9

Ciliated ctenes and locomotion

Answer 9

• Comb rows are used to swim
• Highly organized ciliary beating
• Specialized apical sensory organ controls the beating cilia through a nerve net

Question 10

Ctenes

Answer 10

Are the fused row of cilia

Question 11

Nerve net and the apical sense organ (ASO)

Answer 11

• Non-polar neurons form a simple nerve net (no axons/dendrites)
• Statolith in ASO orients animals
• Tilting provokes balancers, nerve net activated comb rows needed for orientation

Question 12

Haeckelia

Answer 12

• A genus of ctenophores belonging to the family Cydippida
• Hunt jellyfish
  
  • Specifically consume tentacles
  • Cnidarian tentacles have nemotacyts
  • Haeckelia insert the nematocysts (form of kleptocnidism)

Question 13

Nematocytes

Answer 13

• The stinging weapons of cnidarian jellyfish

Question 14

Digestive tract

Answer 14

Have complete unidirectional digestive tracts
- Mouth
- Pharynx; enzymatic and mechanical extracellular digestion
- Muscular organ
- Infundibular zone; center junction
- Endodermal canals; distribution
* Infunibulum
* Transverse canals
* Interradial canals
* Tentacle canals

• Aboral canal: waste from canals
• Anal pores: exits

Question 15

Primary sexual reproduction

Answer 15

• Fertilisation usually occurs in seawater
  
  • Most ctenophores are hermaphrodites
  • Self and cross fertilisation occur
• Larvae are usually cydippid
  
  • Beroida larva do not have a cydippid stage
• Asexual reproduction rarely occurs
  
  • Regeneration of body part to intact animal