cephalopods and intro to annelida

Question 1

what are the defining characteristics of class cephalopoda?

Answer 1

• chambered shell connected by siphuncle
• closed circulatory system (no countercurrent gas exchange, blood is ALWAYS in blood vessels)
• foot modified into arms, tentacles and siphon
• large brain

Question 2

Cephalopods are highly active predators, due to their

Answer 2

• excellent eyesight
• jet propulsion
• grasping arms/tentacles
• beak around mouth

Question 3

Cephalopods have the ________ degree of cephalization in all _______

Answer 3

HIGHEST, IN ALL OF THE INVERTEBRATES

Question 4

cephalopod diversity is highly related to:

Answer 4

• their hunting (can distract prey)
• hiding (can camouflage themselves)

Question 5

While vertebrate intelligence is often linked to socialization and longer lifespans, cephalopods do not have these characteristics. so why are they so intelligent?

Answer 5

• After Cambrian explosion, Cephalopods were the dominant marine predator (ammonites, shelled)
• Then fish evolved (faster, more agile), and put selection pressures on cephalopods
• So cephalopods start to loose their shell, which gave them the abilities to be more agile and faster
• HOWEVER, being shell-less has a cost. Become more vulnerable
• Loss of protective shell selected for intelligence

Question 6

Cephalopod skin has two cells that control colour

Answer 6

• chromatophores, controlling pigment cells
• iridophores, reflective structural cells

Question 7

What are the three segmented phyla in the animal kingdom?

Answer 7

• arthropods, chordates, annelida

Question 8

What is the defining characteristics of the phylum annelida

Answer 8

• chitinous setae, which are hard, small spines
• can be used for locomotion, protection, and suspension feeding

Question 9

what are other major characteristics of phylum annelida?

Answer 9

• veriform (worm like)
• metamerism
• segmented coelom
• gas exchange thru skin
• metanephridium for excretion

Question 10

What is metamerism?

Answer 10

• segmented repetition of organs in body segments

Question 11

what are the three phyla which were ‘demoted’ to be within annelida

Answer 11

• echiura
• sipunculida
• siboglinidae

Question 12

What are the division of classes in annelida based on?

Answer 12

• based on the absence or presence of parapodia (‘side feet’)

Question 13

What are the two classes of annelida

Answer 13

• class clitellata (absence of parapodia)
• class polychaeta (presence of parapodia)

Question 14

What is the defining characteristic of class polychaeta?

Answer 14

• presence of parapodia
  ( fleshy appendages on each segment, stiffened by chitinous spines)