Bony Fish Dicersity And Adaption Flashcards
What are the bony fish called?
Osteichthyes
How many species of bony fish are there?
30,000
What is Osteichthyes divided into?
Ray finned - actinopterygii
Lobe finned - sarcopterygii
What are ray finned fish?
Fish with fins that are made of webs of skin supported by bony or horny spines
What percentage of fish are actinopterygii
99%, from deepest sees to highest mountain streams
Are they varied in size?
Yes, 8mm-11m long bodied par fish
Sunfish 2300kg
What are teleosts?
‘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
How else are teleosts so varied?
- 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
What are otoliths and what can they be used for?
Stony parts of the ear system, carry a complete record of fish growth so can be used to gauge age
What is the primary purpose of fish scales?
Protection
What are the 4 types of fish scales?
Placoid
Cosmoid
Ganoid
Cycloid/ctenoid
What are placoid scales?
Sharks scales (dentine and enamel)
What are cosmoid scales?
Consist of 2 basal layers of bone (lungfish)
What are ganoid scales?
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)
What are cycloid/ctenoid scales?
Majority of teleost fish have these
Cycloid - eg. Trout
Ctenoid - perch
A surface bony layer, then a deeper fibrous layer of collagen
What’s the scale/vertebra arrangement in sea horses tail
Series of bony plates jointed to the central vertebral column
What can cycloid/ctenoid scales be used for?
Provide growth record so ageing
What is the operculum?
A bony plate in teleosts that protects the gills
What is the gas bladder/swim bladder? (Same thing)
Gas filled sac in dorsal region of body cavity, volume can be varied to increase or decrease buoyancy
In what way does a physostigmine fish fill its swim bladder?
Gulp air and burp it back out
In what way does a physoclistous fish fill its swim bladder?
Secrete has into the bladder via the blood stream
Fish have countercurrent exchange along with gas gland to help store oxygen in swim bladder, how does this work?
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
What’s the simplest form of movement in fish
Passive drifters
What provides compression resistance when propulsing in fish?
Vertebral column
What are the 4 types of locomotion in fish?
- anguilliform
- carangiform (subcarangiform)
- ostraciform
- swimming with the fins
What’s the difference between undulation and oscillation
Undulation is a wave passing down the body and fins
Oscillation is when the body moves back and forth
What is anguilliform?
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
What is carangiform/subcarangiform swimming?
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
What is ostraciform swimming?
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
What is swimming with fins swimming
5 types:
- Tetraodontiforms - Sunfish - flap dorsal and anal fins
- Labriform - wrasse - row pectoral fins
- Amiiform - sea horses - undulations pass along dorsal fin
- Gymnotiform - Undulations of a long anal fin (upside down amiiform)
- Balistiform - not anal and dorsal fins undulate
Are fishes specialist or generalist swimmers
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
