Class Polychaeta (Phylum Annelida)

Question 1

Common names

Answer 1

clam worm & fan worm

Question 2

What do they use for locomotion?

Answer 2

• parapodia – little feet
  
  • used for locomotion: alternating contractions of left & right longitudinal muscles
  • contract one side → extend other side → set setae down & repeat process

Question 3

They have prostomium.

What are they?

Answer 3

• 2-4 pairs of “eyes”
• some are eyespots (ocelli) – photosensitive but not capable of vision
• some are well-developed (have cornea, lens)

Question 4

Have peristomium.

What is it?

Answer 4

• the 1st true segment
  
  • equipped w/ sensory tentacles (helps get food in mouth)

Question 5

What is the cuticle and what is it used for?

Answer 5

• Def: non-living outer layer, waxy
• used primarily for water-proofing, hydrophobic
• e.g. earthworm, clam worms
• adaptation to prevent water loss

Question 6

What are statocysts & what are they used for?

Answer 6

• statocysts – structures that help them swim
  
  • sensitive to water currents
  • sensitive to gravity & inertia

Question 7

Reproduction & Regeneration: occur at same time

Asexual

Answer 7

• asexual: fragmentation
• if broken in half, will grow back

Question 8

Reproduction & Regeneration – happen at the same time

Sexual

Answer 8

• sexual: epitoky → generation of a sexually reproducing body form
• grows this piece, it’s fragmented & the piece finds outher pieces like itself → get together & discharge gametes at ocean surface