Unit III: Deuterostomes

Question 1

What are the 2 Deuterostome?

Answer 1

1. Echinodermata
2. Chordata

Question 2

Echinodermata characteristics

Answer 2

Sea stars, sea urchins, sand dollars, sea cucumbers
* Larvae have bilateral symmetry
* Adults have pentaradial symmetry
– Radial symmetry in multiples of five
* Loss of cephalization
– Can interact with environment using all five sides at once

Question 3

Echinodermata body plan

Answer 3

• Endoskeleton: internal skeleton for protection and support made of calcium carbonate
• Mouth on ventral side
• Water vascular system
  – Extends down each arm, ending with tube feet that have tactile and movement functions
  – Tube feet controlled by bulblike
  ampullae

Question 4

What are the defining traits of Echinodermata?

Answer 4

• Adult pentaradial symmetry
• Loss of cephalization
• Water vascular system

Question 5

What are the 3 main chordata lineages?

Answer 5

• Cephalochordata
• Urochordata
• Vertebrata

Question 6

Chordata characteristics

Answer 6

• Notochord
  – Rigid yet flexible
  – Becomes intervertebrate discs in vertebrates
• Dorsal hollow nerve chord
  – Lost in Urochordates
• Pharyngeal gill slits
  – Used for filter feeding in aquatic chordates
  – Only present in embryonic stages of tetrapods
• Post-anal tail

Question 7

Chordata - Urochordata

Answer 7

Known as tunicates
* Tunic: cellulose-like material that covers the body
* Larvae have typical characteristics of chordates, but notochord, dorsal hollow nerve chord, and post-anal tail lost in adults
* Can form long chains called salps

Question 8

What are the defining traits of Chordata?

Answer 8

• Pharyngeal gill slits
• Dorsal hollow nerve chord
• Notochord
• Post-anal tail