Week 8 Clade Chordata Clade Vertebrata

Question 1

Clade Chordata general characteristics

Answer 1

• Triploblastic
• Deuterostomes
• Bilateral Symmetry
• Closed Circulatory System
• Well developed digestive, nervous and excretory systems
• Endoskeleton

Question 2

What are the 5 specific features that all chordates share in development?

Answer 2

1. Notochord- flexible rod-like structure that is the first part of the endoskeleton to appear in the embryo. May be reduced in adults
2. Dorsal nerve tube - vertabrate spinal cord and brain
3. Pharyngeal Gill Slits: perforated slit-like openings that serve in suspension feeding in simpler chordates and as the pharynx in vertabrates
   4: Postanal Tail
4. Endostyle or thyroid gland

Question 3

Taxonomy of Lamprey?

Answer 3

Clade Chordata

• Clade Vertebrata
  
  • Clade Agnatha
    
    • Clade Petromyzontida

Question 4

Taxonomy of Shark?

Answer 4

Clade Chordata
Clade Vertebrata
Clade Gnathostomata
Clade Chondrichthyes

Question 5

What are the members of clade Tunicata (within clade Chordata)?

Answer 5

• Tunicates / Sea Squirts
• Found throughout the sea
• forcefully expel water
• sessile as adults
• suspension feeders

Question 6

What are the members of cephalochordata (within clade chordata)?

Answer 6

• Lancelets / Amphioxus
• Show all of the chordate characteristics as an adult
• Are thought to be the vertebrate ancestor
• Obtain food via filter feeding: burrow into sediments, leaving anterior oral hood w. tentacles exposed, tentacles draw water currents and food particles into the amphioxus, food particles stick to mucous covered and ciliated pharyngeal gill slits

Question 7

Defining characteristics of Clade Vertebrata?

Answer 7

• Series of bone vertebrae that protect the spinal column

- Cranium that surrounds and protects the brain (craniata)

Question 8

Agnatha vs. Gnathostomata

Answer 8

Agnatha (w/o jaws) includes lamprey, hagfish

Gnathostomata (w/ jaws) includes sharks, rays, frogs, turtles, mammals, etc…

Question 9

Characteristics of lamprey

Answer 9

• Lack jaws
• Clade Agnatha, Clade Petromyzontida
• Anadromous (spawn in streams and rivers)
• Larvae are called ammoecoetes. They live in sand of the river for 3-5 years, and then metamorphose quickly
• Lamprey that are parasites attach themselves to fish with a sucker like tongue. Suck out body fluids with the aid of secreted anticoagulants

Question 10

Characteristics of the shark?

Answer 10

Clade Gnathostomata, Clade Chondrichthyes

• Possess jaws
• Well developed sensory organs
• Cartilaginous skeleton
• Heterocercal Tail
• Constant Swimmers
• Well-developed sensory organs
• Placoid scales

Question 11

What are the components of the shark’s sensory system?

Answer 11

• Olfactory organs for smell
• Lateral Line system to sense vibrations
• Ampullae of Lorenzini to sense electrical fields

Question 12

Describe the shark’s circulatory system.

Answer 12

2-chambered heart

Single circuit system (heart->gills->body tissues->heart)