Exam Prep 2 (Fish/octopus/Fins)

Question 1

What is the function of fins?

Answer 1

Dorsal- Balance, Stability, Direction
Pectoral- Direction, Paired fin, Swimming Aid
Pelvic- Deceleration (Brakes)
Anal- Stability

Question 2

What is the function of Caudal Fins?

Answer 2

Primary function - Propulsion/Accelration

Rounded- Acceleration, High drag, Not for long distance
Truncated- Straight edge, rapid turning/speed
Emarginated- Low drag, Two lobes
Lunate- Maintain high speed, low drag

Question 3

What is the function of body shape?

Answer 3

Sagitiform- Elongated, tubular (ambush predators)
Depressiform- Wide, flat (Bottom dwelling)
Compressiform- Latterally compressed, Tall/thin (enters vertical crevices)
Fusiform- Streamlines, pointy, fast movement
Anguilliform- Long, thin, snake like (reduce drag)
Globiform- round, globe shape
Taeniform- Ribbon shaped (Crevices and narrow refuge)

Question 4

What are the 6 basic senses?

Answer 4

Sight
Sound
Smell
Taste
Touch
Electrosense

Question 5

Outline Main Features of Octopus Nervous System?

Answer 5

The Central Nervous system controls arm coordination/ command
The peripheral Nervous system controls muscle

(Optic lobes and nervous system of the arms lay outside the brain capsule)

• 2 large optic lobes
• The arm nervous system, functions autonomously generates coordinated stereotypical movements
• Central brain lies inside the brain capsule and surrounding oesophagus, brain comprises 40 lobes that maintain organisation with outer cell body layers and inner neutrophil

Question 6

What are the general features of sound perception systems across the animal kingdom?

Answer 6

Insect- Fine hair, tympanic membrane and receptor cells

Fish- Complex inner ear structure, vibrations transmitted from swim bladder through Weberian ossicles

Birds/Reptiles- Different external ear anatomy, Similar middle and inner ear anatomy, single auditory ossicle

Mammals- Evolved external ear structure, complex middle and inner ear anatomy

All use vibrations