Animal biodiversity 5 - fish

Question 1

what is the super class agnatha?

Answer 1

without jaws

Question 2

3 features of the Ancient Agnatha- Ostracoderms

Answer 2

1) shell skinned heavily armoured
2) bony plates and scales surfaced in enamel and dentine (like teeth)
3) lacked pectoral fins (poor swimmers)

Question 3

what are the 2 classes of modern agnatha?

Answer 3

1) hag fish

2) lampreys

Question 4

3 features of the body structure of hag fish and lampreys

Answer 4

1) lack paired fins and jaws
2) no armour
3) skeleton cartilaginous

Question 5

how do hagfish feed?

Answer 5

scavengers, enter the body through an opening and eat from the inside out

Question 6

what water do lampreys live in?

Answer 6

adults may be freshwater or marine but they spawn in freshwater and larvae live in the sediment of streams

Question 7

describe the skeletal structure of lampreys

Answer 7

skeleton is made of cartilage containing no collagen in a vertebral column

Question 8

what is the Superclass Gnathostoma 2 features?

Answer 8

1) jaws

2) 2 pairs of appendages

Question 9

state one hypothesis for the evolution of jaws

Answer 9

evolved from 2 pairs of skeletal rods located between gill slits near the mouth, anterior rods either lost or incorporated in cranium

Question 10

describe the class Placodermii

Answer 10

extinct plate skinned heavily armoured jaw fish

Question 11

what are 4 features of the Class Chondrichthyes?

Answer 11

1) flexible endoskeleton made of cartilage
2) tooth like structures called placoid scales
3) developed jaws and paired fins
4) 5 pairs of gill pouches

Question 12

what species does class chondrichthyes include?

Answer 12

sharks, rays, dogfish

Question 13

what are chondrichthyes reproductive strategy?

Answer 13

oviparous, ovoviviparous, or viviparous

Question 14

what is the job of the heterocercal tail and wing-like pectoral fins on chondrichthyes?

Answer 14

provide lift because body is negatively buoyant

Question 15

what are the 4 sense adaptations of Chondrichthyes?

Answer 15

1) sharp vision, not colour
2) cup shaped smell receptors
3) lateral line system to detect pressure changes
4) electroreceptive organs in the head detect electric fields

Question 16

what is the definition of Osteichthyes?

Answer 16

bony fishes with calcium phosphate endoskeleton

Question 17

what is the significant of the gas sac in Osteichthyes?

Answer 17

used for buoyancy and as oxygen reservoir in periods of drought or stagnation

Question 18

how do Osteichthyes keep water flowing across the gills?

Answer 18

gill pouch covered by an operculum, with pharyngeal muscles acting like bellows

Question 19

what are the 3 classes of osteichthyes?

Answer 19

1) ray finned
2) lobe finned
3) lung fish

Question 20

features of the Class Actinistia (lobe-finned fish)

Answer 20

heavy pectoral and pelvic fins which may have walked in tetrapod motion

Question 21

features of the Class Dipnoi (lung fish)

Answer 21

have lungs and nostrils, live in stagnant ponds

Question 22

3 features of the Class Actinopterygii (ray-finned fish)

Answer 22

1) reduced scales for increased mobility
2) better adapted fins and tail for manoeuvrability
3) maxilla is now free and articulated, giving more efficient jaw