Lecture 15 - Locomotion

Question 1

Give the equation for Reynold’s number.

Answer 1

(animal length x velocity) / kinematic viscosity

Question 2

What is viscosity?

Answer 2

How thick water feels to an animal.

Question 3

What is the Reynold’s number of

a) Whales?
b) Microorganisms?

Answer 3

a) Whales = 10^8

b) Microorganisms = 10^-5

Question 4

Explain how Paramecium move.

Answer 4

• A unicellular ciliated protozoan
• Cilia beat together in unison (metachronal rhythm), with a high friction power stroke then a low friction recovery stroke.

Question 5

Why are sperm vulnerable to low pH in the ocean?

Answer 5

Due to the proton gradient required for flagella to beat.

Question 6

What is jet propulsion?

Answer 6

Filling a muscular cavity then forcing out water by muscular contractions, creating a jet.

Question 7

Describe jet propulsion in radiates such as jellyfish.

Answer 7

Flex their cup-shaped body.

Use to maintain position for feeding.

Question 8

Describe the jet propulsion of cephalopods.

Answer 8

Expand their mantle to suck in water, then contract and force water out through the hyponome, forming a directional jet.

Question 9

Describe the jet propulsion of salps.

Answer 9

Pump in water at the front, filter it, then expel it from the rear.

Question 10

How do scallops use jet propulsion?

Answer 10

As an escape mechanism from starfish.
Detect starfish by olfactory stimuli; open and close their shells, drawing in water and expel it, to swim away from danger.

Question 11

What is the froude propulsion efficiency?

Answer 11

The ratio of power output to the power input.

Question 12

Give the equation for froude propulsion efficiency.

Answer 12

Nf = 2U1 / (U1 + U2)

Where:
U1 = free stream velocity
U2 = jet velocity

Question 13

What is the froude propulsion efficiency of

a) Jellyfish
b) Squid
c) Scallops
d) Herring

Answer 13

a) Jellyfish = 0.09
b) Squid = 0.29
c) Scallops = 0.3
d) Herring = 0.85

Question 14

What does the froude propulsion efficiency of jellyfish mean?

Answer 14

That 9% of the effort jellyfish put into moving is converted into directed movement.

Question 15

What are the names of the paddles in polychaete?

Answer 15

Parapodia

Question 16

Describe movement in crustaceans.

Answer 16

• Have elaborate antennae, allowing movement through water, and to lock themselves into the water column.

Question 17

Give four groups of organisms that use paddles for swimming.

Answer 17

• Polychartes
• Crustaceans
• Turtles
• Featherstars

Question 18

What are body undulations?

Answer 18

Using the whole body to move through a coordinated, snake-like body motion.

Question 19

What percentage of all animals known of on Earth are Nematode worms?

Answer 19

80%

Question 20

Describe the movement of finned chaetognaths (arrow worms).

Answer 20

• One or two pairs of lateral fins for stabilisation and steering
• A caudal fin for propulsion
• Burst of swimming with torso-ventral undulating motion

Question 21

Describe the swimming methods of fish.

Answer 21

Use paired musculature down their bodies to generate waves of flexion.

Question 22

What is anguilliform swimming?

Give an example of a fish that uses anguilliform swimming.

Answer 22

No change in amplitude.
Often several wavelengths per body length of the fish.
Allows them to go forwards and backwards.
Head moves as much as tail.

Example: eels.

Question 23

What is sub-carangiform swimming?

Give an example of a fish that uses this method.

Answer 23

Most of the work is done by the tail.

Example: trout

Question 24

What is carangiform swimming?

Give an example of a fish that uses this method.

Answer 24

Stiffer body.
Fast beating of the tail end.

Example: mackerels

Question 25

What is thunniform swimming?

Give an example of fish that use this method.

Answer 25

All the thrust comes from the crescent-shaped tail and peduncle.

Example(s): Tuna, white sharks, salmon.

Question 26

What is ostraciiform swimming?

Give an example of fish that use this method.

Answer 26

No body movement, but rapid fanning of the tail.

Example(s): Boxfish, seahorses.

Question 27

Name a fish that swims using oscillating pectoral fins.

Answer 27

Parrotfish

Question 28

How do sharks maintain depth?

Answer 28

• No swim bladder
• Instead use dynamic lift
• Pectoral fins act as wings for sharks to provide upthrust; must keep swimming, cannot hover or swim backwards.
• Also store squalene in liver, lower density than water.

Question 29

How can a swim bladder be filled up?

Answer 29

By gulping air, or by gassing out predominantly oxygen, at pressures up to 100 bars.

Question 30

Describe endothermy in tuna.

Answer 30

Heat is harvested in veins through the rete mirabile, and returned to the arteries via counter-current exchange.