Bony Fish Dicersity And Adaption

Question 1

What are the bony fish called?

Answer 1

Osteichthyes

Question 2

How many species of bony fish are there?

Answer 2

30,000

Question 3

What is Osteichthyes divided into?

Answer 3

Ray finned - actinopterygii

Lobe finned - sarcopterygii

Question 4

What are ray finned fish?

Answer 4

Fish with fins that are made of webs of skin supported by bony or horny spines

Question 5

What percentage of fish are actinopterygii

Answer 5

99%, from deepest sees to highest mountain streams

Question 6

Are they varied in size?

Answer 6

Yes, 8mm-11m long bodied par fish

Sunfish 2300kg

Question 7

What are teleosts?

Answer 7

‘Perfect bone’ most advanced of the living fishes
96% or all fishes
They inhabit the greatest range of habitats, show the greatest variation in body plans, foraging and reproductive of any fishes

Question 8

How else are teleosts so varied?

Answer 8

• there are flying, walking and immobile
• ones that brood eggs and young in mouth, others lay eggs in clams
• feed on other fish, carrion, invertebrates, mammals, scales, eyes, eggs and zooplankton
• only true endoparasitic organisms
• can produce light and electricity

Question 9

What are otoliths and what can they be used for?

Answer 9

Stony parts of the ear system, carry a complete record of fish growth so can be used to gauge age

Question 10

What is the primary purpose of fish scales?

Answer 10

Protection

Question 11

What are the 4 types of fish scales?

Answer 11

Placoid
Cosmoid
Ganoid
Cycloid/ctenoid

Question 12

What are placoid scales?

Answer 12

Sharks scales (dentine and enamel)

Question 13

What are cosmoid scales?

Answer 13

Consist of 2 basal layers of bone (lungfish)

Question 14

What are ganoid scales?

Answer 14

Rhomboid in shape, have peg and socket joints between them

Consist of basal bony layer, a layer of dentine, then outer layer of ganoine (sturgeon)

Question 15

What are cycloid/ctenoid scales?

Answer 15

Majority of teleost fish have these
Cycloid - eg. Trout
Ctenoid - perch
A surface bony layer, then a deeper fibrous layer of collagen

Question 16

What’s the scale/vertebra arrangement in sea horses tail

Answer 16

Series of bony plates jointed to the central vertebral column

Question 17

What can cycloid/ctenoid scales be used for?

Answer 17

Provide growth record so ageing

Question 18

What is the operculum?

Answer 18

A bony plate in teleosts that protects the gills

Question 19

What is the gas bladder/swim bladder? (Same thing)

Answer 19

Gas filled sac in dorsal region of body cavity, volume can be varied to increase or decrease buoyancy

Question 20

In what way does a physostigmine fish fill its swim bladder?

Answer 20

Gulp air and burp it back out

Question 21

In what way does a physoclistous fish fill its swim bladder?

Answer 21

Secrete has into the bladder via the blood stream

Question 22

Fish have countercurrent exchange along with gas gland to help store oxygen in swim bladder, how does this work?

Answer 22

CO2 is transferred to the incoming arterial blood, joined by CO2 from gas gland, forms carbonic acid, decreasing pH of blood, lower pH means less affinity of oxygen to haemoglobin, so oxygen diffuses into swim bladder

Question 23

What’s the simplest form of movement in fish

Answer 23

Passive drifters

Question 24

What provides compression resistance when propulsing in fish?

Answer 24

Vertebral column

Question 25

What are the 4 types of locomotion in fish?

Answer 25

• anguilliform
• carangiform (subcarangiform)
• ostraciform
• swimming with the fins

Question 26

What’s the difference between undulation and oscillation

Answer 26

Undulation is a wave passing down the body and fins

Oscillation is when the body moves back and forth

Question 27

What is anguilliform?

Answer 27

Undulatory waves passing down flexible bodies such as eels
All the body but the head contributes to the motion
As the wave moves posteriorly it increases in amplitude

Question 28

What is carangiform/subcarangiform swimming?

Answer 28

Used in faster swimmers, only posteriors segments of the body are involved
Use ligaments to transfer force from muscles to caudal region
Advanced ones use only tail, not the body
Hinge allows fish to maintain tail at ideal attack angle of 10-20
Thuniform is advanced carangiforms, they have very narrow peduncle with lateral jerks to reduce drag

Question 29

What is ostraciform swimming?

Answer 29

Only tail oscillates while body remains rigid
Used in boxfish
These fishes rely on armour rather than speed for protection
The caudal fin is small and not differentiated into lobes

Question 30

What is swimming with fins swimming

Answer 30

5 types:

1. Tetraodontiforms - Sunfish - flap dorsal and anal fins
2. Labriform - wrasse - row pectoral fins
3. Amiiform - sea horses - undulations pass along dorsal fin
4. Gymnotiform - Undulations of a long anal fin (upside down amiiform)
5. Balistiform - not anal and dorsal fins undulate

Question 31

Are fishes specialist or generalist swimmers

Answer 31

Most fishes have specialist swimming, but are able to swim in other ways to a reduced effectiveness, as may spend most time swimming on slowly, but need to swim rapidly to eat/avoid being eaten