Class Chondrichthyes

Question 1

What phylum is it in and subphylum?

Answer 1

Chordata and Vertebrata

Question 2

What is the class that includes sharks, skates, rays, and chimaeras?

Answer 2

Chondrichthyes

Question 3

What does Chondrichthyes mean?

Answer 3

cartilage fish

Question 4

What type of body do sharks have?

Answer 4

Fusiform body

Question 5

What type of caudal fin do sharks have?

Answer 5

Heterocercal caudal fin

Question 6

What are the fins like?

Answer 6

paired pectoral & pelvic fins; one or two median dorsal fins

Question 7

What is the mouth like?

Answer 7

ventral mouth; two olfactory sacs that do not connect to the mouth cavity; jaws present

Question 8

What does the skin have?

Answer 8

placoid scales and mucous glands

Question 9

What is the teeth like?

Answer 9

teeth of modified placoid scales

Question 10

What is the endoskeleton made of?

Answer 10

cartilage

Question 11

What is the digestive system like?

Answer 11

Digestive system with J-shaped stomach & intestine with spiral valve

Question 12

what is the circulatory system like?

Answer 12

closed with two chambered heart (atrium and ventricle)

Question 13

what is respiration like?

Answer 13

5 to 7 pairs of gills with separate and exposed gill slits; no operculum

Question 14

What does it not have?

Answer 14

no swim bladder or lung

Question 15

What are the senses like?

Answer 15

senses or smell, vibration reception (Lateral Line System), and electroreception well developed

Question 16

What type of reproduction and fertilization do sharks have?

Answer 16

Oviparous with internal fertilization and direct development

Question 17

What types of reproduction are there?

Answer 17

Oviparous (lay eggs), Ovoviviparous (live birth), and Viviparous (fertilization and embryo development occur inside the individual)

Question 18

What is the most anterior part of the shark?

Answer 18

Rostrum

Question 19

Sharks are naturally buoyant because they lack a _____ (they sink bc)

Answer 19

they lack a swim bladder

Question 20

What do spiracles do?

Answer 20

allows water to pass through gills

Question 21

What is in a shark’s digestive system that increases their surface area?

Answer 21

Spiral valve

Question 22

What has to do with a shark’s sense of hearing and is behind the eyes connected to the inner ear

Answer 22

Endolymphatic pores

Question 23

What is a shark’s sense of smell like?

Answer 23

-ventral nostrils not connected to mouth cavity
-most of the brain is dedicated to smell (large olfactory lobe)

Question 24

What is the special receptor organs in a shark’s sense of distant touch called?

Answer 24

Neuromass

Question 25

What are characteristics of a shark’s sense of vision?

Answer 25

-good vision even in dim lights
-they have stereotypical vertebrate eyes
-can’t see color bc. they lack cones for color vision & detail

Question 26

What is the small jelly-filled pores in a shark’s sense of electroreception?

Answer 26

Ampullae of Lorenzini

Question 27

What is the shark’s sense of electroreception?

Answer 27

-capable of detecting prey buried under sand