Fish Class Chondrichthyes (exam 5)

Question 1

class Chondrichthyes

Answer 1

cartilaginous fish
sharks, rays
850 species

Question 2

length

Answer 2

6.5 inches (dwarf lantern shark) to 45 ft (whale shark)

Question 3

endoskeleton

Answer 3

cartilage instead of bone; no ribs

Question 4

dermal denticles

Answer 4

skin feels rough like sand paper (oriented in same direction) = improved fluid dynamics

Question 5

teeth

Answer 5

in multiple rows along the edges of the upper and lower jaws (not attached to the jaw, but embedded in the flesh); constantly replaced throughout their life
some can lose 30,000 teeth in a lifetime

Question 6

heart

Answer 6

have 2 chambered heart

Question 7

Leydig’s organ

Answer 7

red blood cell production (also spleen and special tissue around the reproductive organs)

Question 8

respiration

Answer 8

5-7 gills: water inhaled through the mouth which then passes over the gills (continual swimming)

Question 9

fins

Answer 9

dorsal, caudal (tail) fins: anal, pelvic and pectoral fins (paired)

Question 10

buoyancy

Answer 10

sharks do not have a gas filled swim bladder like bony fish, but instead rely on a large liver filled with oil (squalene); the liver may constitute up to 30% of their body mass

Question 11

squalene

Answer 11

lighter than water = reduction in body density

Question 12

sense of smell

Answer 12

sharks have keen olfactory senses with, some species able to detect as little as one part per million of blood in seawater; some species have external barbels that greatly increase their ability to sense prey.

Question 13

lateral line

Answer 13

a sense organ, usually running lengthwise from the gills to the tail, that is used to detect movement and vibration in the surrounding water

Question 14

electroreception

Answer 14

ampullae of Lorenzini: electroreceptor organs in sharks (100-1000s) which allow the shark to detect the electromagnetic fields which 1) enhance ability to find prey and 2) aid with orientation and navigation

Question 15

reproduction

Answer 15

sexual

Question 16

ovoviviparous

Answer 16

embryo develops inside eggs that are retained inside female (no placental connection, young, nourished by egg) until they are ready to hatch

Question 17

viviparous

Answer 17

embryo development inside female (placental connection) results in live birth

Question 18

oviparous

Answer 18

lay eggs

Question 19

shark fin soup

Answer 19

sharks are killed for their fins that are used in making soup. Finning process includes removal of fin and then throwing the finless shark into the water cause its death.