Vertebrates 11.1 - Swimming

Question 1

Primary and secondary swimmers

Answer 1

Primary have always swam, secondary have returned to water from an ancestor that was terrestrial

Question 2

Primary and secondary swimmers examples

Answer 2

Primary: fish and aquatic amphibians; Secondary: sea turtles, penguins, alligators, pinnipeds, cetaceans.

Question 3

Undulatory groups

Answer 3

Trunk and tail: Anguiliform, carangiform, thunniform, ostraciform. Undulatory with paired fins ok too.

Question 4

Anguliform

Answer 4

use most of body in undulation. Eels

Question 5

Carangiform

Answer 5

About half of body (caudal) undulates. Jack fish and alligator.

Question 6

Thunniform

Answer 6

Use just the back part of the tail. Tuna. The best form of swimming, creates the least drag.

Question 7

Ostraciform

Answer 7

Just the tail moves. Rest of body rigid. Boxfish.

Question 8

Undulatory with paired or unpaired fins

Answer 8

Stingray, bowfin, seahorse

Question 9

Oscillatory swimmers

Answer 9

More like paddling. Used paired fins or legs. Frogs, beaver, sea turtle, penguins, duck, swan, perch

Question 10

Role of fins

Answer 10

Caudal: generally big, thrust. Others are for stability and direction.

Question 11

Pitch

Answer 11

Movement up and down. In fish created by extending or flexing both fins on both side (pectoral and pelvic)

Question 12

Yaw

Answer 12

Movement side to side. In fish created by extending one fin and flexing the other.

Question 13

Rolling

Answer 13

Controlled with the dorsal and anal fins, provide stability.

Question 14

Were ancient fish good swimmers?

Answer 14

Streamline, caudal fin ok. But lacking the dorsal fins and pectoral fins pretty weak, so not very good. Dermal armour heavy and not flexible

Question 15

Problems with water locomotion

Answer 15

Drag, buoyancy, and specific heat (esp for secondary swimmers)

Question 16

Overcoming Drag

Answer 16

Water is dense, so it creates drag. Fusiform shape helps. (rounded at front end, tapered at other). Mucous makes boundary layer (water interacts with it, less drag).

Question 17

Slow vs fast swimming

Answer 17

Slow: frictional drag. Fast: eddies/vortices create pressure drag (acts like vacuum). To go fastest, need to minimize movements but provide enough thrust. Balance.

Question 18

Buoyancy

Answer 18

Depends on density of the animal. Most will sink naturally, but most have mechanisms to overcome

Question 19

Buoyancy mechanisms of chondrichthyes

Answer 19

Cartilage is less dense than bones. Lots of lipids in liver (squalene). Shape helps maintain buoyancy (tail thrusts down a bit, head gives a bit of lift), fins lift.

Question 20

Buoyancy mechanisms of osteichthyes (ray fins)

Answer 20

Swim bladder. It’s a membraneous sac associated with blood vessels. Regulates amount of gas in it. Head and tail don’t really affect buoyancy.

Question 21

Problems with specific heat of water

Answer 21

Ectotherms ok because their body temperature can fluctuate without problems. Endotherms (cetaceans, some birds) need core temperature to be constant, use subcutaneous fat.