Lecture 15 - Locomotion Flashcards
Give the equation for Reynold’s number.
(animal length x velocity) / kinematic viscosity
What is viscosity?
How thick water feels to an animal.
What is the Reynold’s number of
a) Whales?
b) Microorganisms?
a) Whales = 10^8
b) Microorganisms = 10^-5
Explain how Paramecium move.
- A unicellular ciliated protozoan
- Cilia beat together in unison (metachronal rhythm), with a high friction power stroke then a low friction recovery stroke.
Why are sperm vulnerable to low pH in the ocean?
Due to the proton gradient required for flagella to beat.
What is jet propulsion?
Filling a muscular cavity then forcing out water by muscular contractions, creating a jet.
Describe jet propulsion in radiates such as jellyfish.
Flex their cup-shaped body.
Use to maintain position for feeding.
Describe the jet propulsion of cephalopods.
Expand their mantle to suck in water, then contract and force water out through the hyponome, forming a directional jet.
Describe the jet propulsion of salps.
Pump in water at the front, filter it, then expel it from the rear.
How do scallops use jet propulsion?
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.
What is the froude propulsion efficiency?
The ratio of power output to the power input.
Give the equation for froude propulsion efficiency.
Nf = 2U1 / (U1 + U2)
Where:
U1 = free stream velocity
U2 = jet velocity
What is the froude propulsion efficiency of
a) Jellyfish
b) Squid
c) Scallops
d) Herring
a) Jellyfish = 0.09
b) Squid = 0.29
c) Scallops = 0.3
d) Herring = 0.85
What does the froude propulsion efficiency of jellyfish mean?
That 9% of the effort jellyfish put into moving is converted into directed movement.
What are the names of the paddles in polychaete?
Parapodia
Describe movement in crustaceans.
- Have elaborate antennae, allowing movement through water, and to lock themselves into the water column.
Give four groups of organisms that use paddles for swimming.
- Polychartes
- Crustaceans
- Turtles
- Featherstars
What are body undulations?
Using the whole body to move through a coordinated, snake-like body motion.
What percentage of all animals known of on Earth are Nematode worms?
80%
Describe the movement of finned chaetognaths (arrow worms).
- One or two pairs of lateral fins for stabilisation and steering
- A caudal fin for propulsion
- Burst of swimming with torso-ventral undulating motion
Describe the swimming methods of fish.
Use paired musculature down their bodies to generate waves of flexion.
What is anguilliform swimming?
Give an example of a fish that uses anguilliform swimming.
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.
What is sub-carangiform swimming?
Give an example of a fish that uses this method.
Most of the work is done by the tail.
Example: trout
What is carangiform swimming?
Give an example of a fish that uses this method.
Stiffer body.
Fast beating of the tail end.
Example: mackerels
