Lecture 11 Pt. 1

Question 1

Morphological mosaics

Answer 1

• Small goblet shaped upper body (calyx) with tentacles, lower half attached to stalk; somewhat resembles cnidarian polyps
• Tentacles ciliated to generate water current towards mouth

Question 2

Head anatomy of the ‘anus first’

Answer 2

• Crown of feeding tentacles
  
  • usually horse shoe shaped
• Mouth along the rim of the tentacles crown, anus opens on a small cone within the atrium
• The majority of musculature and neural specialization in Ectoprocta relate to control of the tentacles/cilia

Question 3

Digestive journey

Answer 3

• Lateral tentacle cilia create water currents to trap phytoplankton; suspension feeding strategy
• Cilia band of the food groove passes food to the mouth
• Cilia lining buccal funnel and muscles pass food into the esophagus, u-shaped complete gut
• Prey enters stomach
  
  • Lining secretes digestive enzymes and mucous
  • Short intestine and stomach absorb nutrients

Question 4

Excretory systems

Answer 4

• Paired protonephridium along the stomach empty into the atrium through nephridoducts
  
  • Excretory organ made of flame cells
• Cells lining the ventral gut also accumulate and release brown spheres that are excreted from the anus

Question 5

Circulatory system and respiration

Answer 5

• Ciliated stomach circulates contents; pseudo-circulatory system
• Mesenchyme think enough to permit diffusion to occur for some respiration and CO2/NH3 release
• No true circulatory system

Question 6

Colonial

Answer 6

• Star-cell functions as a simple pulsating heart
  
  • Fluid pumped from the calyx through the stalk amongst the stolon that connect individuals
• Individuals have their own muscles; retract crown

Question 7

Solitary

Answer 7

• Sessile; similar locomotory as colonial
• Possess adhesive organ at the base of the foot

Question 8

Nerves and sensory systems

Answer 8

• Singular dumbbell-shaped subenteric ganglia extends nerves to tentacles body wall and stalk
  
  • Sessile life
• Nerves run below the epidermis and along the mesenchyme
• Most sensory functions relate to the cilia along the tentacles

Question 9

Reproduction

Answer 9

• Hermaphroditic or protandric
• Budding
• Sexual
  
  • Gonoducts lead from gonads to the atrium that acts as broad chamber
    
    • Sperm released into water, enters oviducts to fertilise embryo
    • Zygote covered in tough membrane to stick them to atrium; released at maturity to settle nearby…
      OR
    • Released as swimming larvae

Question 10

Protandric

Answer 10

Hermaphroditic animals that develop as males, but can later reproduce as females

Question 11

Three enigmatic phyla

Answer 11

1.) Entoprocta (200 species)
2.) Cycliophora (2 species)
* Diverse body plans
* Superficially variable but somewhat similar anatomically to another
3.) Dicyemida
* Unsual phyla, solely grouped by protostomian and spiralian development
* Lack the jaws of gnathifera, the suction feeding of rouphozoa, the molecular features of lophotochozoan