Fish Flashcards
Hagfish
Craniate
Chordate - non vertebrate
Marine
Scavengers
Cartilage + skull
Lack jaws + vertebrae
feed on internal organs by going through gills or anus
Tooth plates around protrudable tongue
Body knotting
Jawless fish
Agnathans
Diadromous
Lives in marine + fresh in life cycle
Anadramous
Breeds in fresh
Rest of life in marine
Catadromous
breeds in marine
Lives life in fresh
Sea lamprey
No paired fins
Dorsal + caudal fins
Buccal funnel - suckers - mobile tongue - teeth
Large eyes
anticoagulant - keep blood flowing
No stomach
Nostril just for smelling
wash water over gills while feeding to breathe
Evolution of jaws
Serial theory - evolution from branchial arches
Branchial arches migrate forming hyoid and mandibular arch
Gnathostomes
Jawed vertebrates with mineralised skeleton
Chondrichthyes
Chimeras
Extinct Gnathostomes
Placoderms
demersal/benthopelagic
Heavy head shield
Tooth plates - sharp for cutting - flat for grinding
Extant gnathostomes
Chondrycthyes
Elasmobranchs (sharks + rays) + Holocephalans (chamaeriformes - rabbit/rat fish)
Cimaeriformes
Rabbit + rat fish
Benthic pred of inverts
Fairly deep water
Have operculum and no separate gill slits
Cartilagenous flap over gills
Condricthyes scales
Placoid scales
Dermal denticels
small
Rough
Allow skin to flex
decrease in friction
come through dermis + epidermis
Layer of enamel over dentine interior around pulp cavity
Similar structure to teeth
Serial tooth eruption
Constant tooth replacement
Always teeth forming
replacement as high as every week
Buoyancy is elasmobranchs
Relatively dense - good for benthic rays - bad for pelagic sharks
Sharks must generate lift
Dynamic lift - requires movement - heterocercal tail - hydroplane pectoral fins
Static lift - LD oils in body - lowers density - stored in liver - squalene - liver is 25% body mass
Osmoregulation
Water tends to flow out - ions in
High urea concentration to retain water
ion pump in gills + rectal glands - get rid of ions
Freshwater - lower blood ion and urea conc
Gills of sharks
5-7 gill pouches - open independently
Spiracle - vestigle gill slit found between hyoid and mandibular arches
Gill slits spread between branchial arches
Jaw protrusion of sharks
hyoid and mandibular arches can swing forward
Ventral + forward jaw shift
Manta rays
pelagic filter feeders
enlarged filter feeders
Reproduction of elasmobranchs
Internal fertilisation
Males have claspers to help transfer
Oviparity - eggs laid + develop outside female in mermaids purse (skates + some sharks)
Viviparity - internal brooding - yolk sac placenta transfer (some sharks and rays
Ovoviparity - internal brooding - no transfer of nutrients (most sharks)
Parthenogenesis - asexual (hammer and bamboo)
Sensory systems in elasmobranchs
Vision - low light adaptions - tapetum in eyes
Ears - detect vibrations via sound pressure waves
Lateral line - mechanosensory - line of longitudinal pores - cilia + cupula jelly
Olfaction - v good
Passive electroreception - detection of E fields of others - ampullae of Lorenzi - head/nose of shark/ wings of rays
Osteichthyes
Bony fish
Sarcopterygii - fleshy finned fish
Actinopterygii - ray finned fish
Actinopterygii
Ray finned
Largest group of jawed fish
Chindrostei
Neopterygii
Chondrosteans
Sturgeons - grow to 8m
Heterocercal tail
Anadromous - live in salt - breed in fresh
20 years to mature - live up to 100
American paddlefish - paddle has electroreceptors - can detect individual zooplankton
Bichir - lungs (not lungfish) - internal gas bladder - drown if don’t inhale fresh gulps of air
Secondary loss of bone - mainly cartilage - presence of spiricle
Ganoid scales - enamel - vascular bone - lamella bone
Types of scales
Cosmoid - Enamel - dentine - vascular bone - lamella bone (sarcopterigians)
Ganoid - Enamel - vascular bone - lamella bone (Chondrosteans)
Cycloid - Lamella bone only (teleosts)
Ctenoid - lamella bone only (teleosts)
Neopterygians
Holosteans
Teleosts
Holosteans
Bowfin/Gar
Primitive
Partial freeing of upper jaw from cheekbone - efficient feeding
Lighter scales than chondosteans
Teleost swim bladders
lowers density of teleost
evolved from ancestral lung
Outer layer-guanine crystals + elastic fibres
inner layer - collagen + smooth muscle + nerves to detect change in gas volume
Types - physostomous (pneumatic duct connected to gut) + physoclistous
Gas gland
Rete mirabile - knot of capillaries
Gas enters at bottom + leaves at top (ovale)
Can achieve neutral buoyancy
Energetically efficent
Dynamically unstable - no rapid changes in depth
Large depth migrators - was esters instead - lantern fish
Modified swim bladder function
Sound reception - act as a hydrophone via ossicles (carp, minnows + related fish)
Sound production - Large - use as drum - vibrates - courtship - communication (cod/gurnard)
Gas exchange - use like lung - closely related evolutionary
Teleost muscles
Arranged in efficient blocks of red and white
Red - thin sheet under skin - high mitochondria - continuos swimming
White - runs helically - anaerobic high speed swimming
Teleost locomotion
Muscles contract in waves from nose to tail
Different modes of teleost swimming
Anguilliform - almost whole body movement - eels
Subcarangiform
Carangiform
Thunniform
Ostraciliform - only tail fin ocillates
Tails
Heterocercal - chondostteans
Homocercal
Fins
Lepidotrichia - fin rays
Less motile fish have pelvic fins further forward
some lost pelvic fins
Roll - Median fins (dorsal and anal)
Yore - Pectoral fins
Pitch - pelvic and pectoral
Fin modifications
Sexual selection
Anglerfish lure - first ray of dorsal
Protection and prey capture - lion fish
Wings for gliding - flying fish
Spines for walking - pectoral fin rays - gurnards
fused pelvic - form sucker/anchor - gobies
Pectorals can hold body weight - loco on land - mudskipper
Sucker like dorsal - remora
Non teleost ray finned Jaws
Fused - moveable maxilla + premaxilla
Rapid opening of jaw - pushes food + water away from the mouth
Teleost Jaws
Unfused - decoupling + jaw kinesis - from protrusible jaw
Mouth cavity expands laterally
Water movement into mouth via suction
Better prey handling and swallowing
Pharyngeal jaws - modified gill arches into second set of jaws - moray eels
Teleost teeth
Vililform - elongate needle like - viper fish
Bladelike - triangular - piranha
Caniniform - fang like - snapper
Cardifrom - numerous, small pointed sand paper like
Molariform - flattened, crushers, grinders - sheepshead
Ram feeders
Feed on the swim - filter/chase prey/suction
Oral manipulators
scrape and bite
Gills
Opercular gills
Gill arch
Rakers
Filament
counter current flow - 85% extraction
Osmoregulation
Freshwater - hypertonic - low skin permeability to ions + water - very dilute urine - active uptake of salts via gills + kidney
Seawater - hypotonic - low skin permeability to ions + water - low urine production - concentrated - Drink sea water and excrete salts
Diadromous species - change physiology when between sea + freshwater
Protogynous hermaphroditism
Female - male (dominant male in group)
Protandrous hermaphroditism
Male - female (dominant female)
True hermaphrodite
Both ovaries + testies active
Self fertilisation
Mangrove killi fish
Iteroparity
Reproduce several times
Semelparity
Breed once then die ‘big bang’ - salmon + eels
Migrations
Spawning seasonality
Anadramous
Sea - freshwater
Potadromous
Entirely in fresh
Oceanodromous
Entirely marine
Catadrmous
Fresh to sea
Sarcopterygians
Lobe finned fish
Actinistia
Dipnoi
Actinistia
Coelacanths
Large with fleshy fins
Muscles outside body - homologous to tetrapod limb bones
Live young
Single male paternity
Dipnoi
Lungfish
Powerful jaws - crushing teeth
Paired fins - thick central lobe (bone, muscle and fin rays)
Lungs retained - gulp air - allows for survival in stagnant water with low pp of O2
4 African species - bite out mud in dry seasons to form burrow - mucus cocoon - breathe air via mud tube to surface - ventilate lungs once an hour - survive 4 - 6 months
