Card Set Information
Bio of Fishes Final Exam (post-midterm)
What is a shoal?
groups of fish remaining together for social reasons
What is a school?
synchronized and polarized swimming groups
What 2 cues do fish use to school?
What are the 2 main structures of schools?
shape depends on function
usually a single species, can be mixed
What are the 4 advantages of schooling?
What are the ways of avoiding predation in schools?
simple avoidance - pred req. narrow search field
evasion - from swift cooperative behavior
What are the costs to foraging in schools?
increased competition for food already found
What are the benefits of foraging in schools?
faster location of food
more time for feeding
What are the advantages of migrating in schools?
more accurate homing of salmon
culture transfer of information (juv. learn where to forage)
What is migration?
mass movement from one habitat to another
involves regularity in time, or according to life history stage
can be active or passive
used for feeding, breeding, or wintering
What are the 3 main types of migration (based on water types)?
diadromy (3 subsets)
oceanodromy - wholly w/i SQ
potamodromy - wholly w/i FW
What are the 3 subsets of diadromy?
anadromy - SW to FW to breed
catadromy - FW to SW to breed
amphidromy - not for breeding, both FW and SW
What are the 3 main types of migration (based on strategy)?
wintering - climate factors
spawning - gametic/larval factors
feeding - trophic factors
What types of navigational cues to fishes use to migrate?
olfactory - imprinting (common)
What is the primary purpose of swimming?
avoid being eaten
*very strong selective force
What has the swimming system evolved to do?
minimize energy req (pikes)
increase accel. and speed (tuna)
improve maneuverability (perch)
compromise bw and fine tuning of these 3
What is motion?
a balance bw two hydrodynamic forces
What is resistance equal to?
inertia + drag
What is inertia?
energy req. to start something in motion
What is drag?
force that acts backwards along the direction of motion
What is friction drag?
"stickiness" of water along side
water molec. bouncing off fish
proportional to velocity of water or fish and body surface area
What is pressure drag?
caused by distortions of flow around fish's body
net pressure diff. bw head (hi pressure) and tail (lo pres.)
proportional to velocity and body shape
How can drag be minimized?
fusiform body shape
tuck fins into folds in body
vortex generators - stabilize boundary layer)
What 2 forces enhance propulsion?
What is lift?
force perpendicular for direction of motion
What is thrust?
linear force exerted by fish to propel itself
What are the 2 ways to generate thrust?
undulatory (head to tail)
oscillatory (side-to-side; paired and caudal fins)
What are the 2 components of normal force?
side (lateral) - cxl when body/tail move back and forth
thrust (fwd, along length of body)
How are contractions generated to create undulatory motion?
interaction bw skeleton (head/skull, vertebral columns, appendicular), muscles and fins
What are the components of the vertebral column?
vertebrae with centra, neural spine (dorsal; spinal cord), hemal spine (ventral; caudal veins/arteries)
hemal spine in body cavity mod. into pleural rib
ligaments attach centra (flexible)
What skeletal feature helps with braking and maneuverability?
appendicular skeleton - pelvic and pectoral girdles
What are the components of the pectoral fin/girdle?
pect. fins attach at base of girdle
What are the components of the pelvic fin/girdle?
basipterygia attach pelvic fin to girdle (not to vert. column)
What are the 3 main muscle types?
flexors - extensors (lateral musc)
protractors - retractors
adductors - abductors
What do flexors and extensors do?
lateral musc. along sides of body move vert. side to side
What do protractors and retractors do?
erect and depress doral and anal fin
What do adductor and abductors do?
move paired fins twds and away from body
How does cruising work?
wave of contraction down length of body
spinal nerves linked to myomere
wave of innerv. contracts in sequence
How does acceleration work?
all musc. on one side contract simultaneously
Mauthner cells (giant axons) in teleosts
What is red muscle good for?
slow contractions; cruising
little mass (superficial only)
lots of myoglobin
more extensive vein/cap. develp
slender, longer; faster diffusion
higher density of mitochondria (oxidative metabolism)
more fat; fast recovery (aerobic)
What is white musc. good for?
faster contraction speed, rapid burst (fatgiues quickly)
lots of mass
lower blood supply
thicker and shorter
low density mitochondria
less fat (anaerobic)
What are the 2 kinds of fins used in oscillatory swimming?
What are wing-like fins?
thrust generated like a wing and generates lift
ie. caudal fin of tuna
What are the advantages to a narrow caudal peduncle and wing-like fins?
minimal drag, very efficient
fast once started
What are the disadvantages of wing-like fins?
poor quick start
What are oar-like fins?
use pectorals to scull like oars
push water back (power stroke) and return collapsed fins horizontally
-figure 8 motion
What are the 5 major fins?
What is the main function of the caudal fin?
propulsion (und, osc) and as vane/rudder
What is the main function of the dorsal and anal fin?
What is the main function of the pelvics?
act as hydrofoils
What is the main function of the pectorals?
turning and brakes
What is the advantage to depth regulation (buoyancy)?
vertical structuring of food, predation, temperature, light, oxygen
What is depth regulation?
generating lift because fish will tend to sink
How do you generate lift?
pectoral fins in sharks/tuna
heterocercal tail of sharks
hover via pectorals
What is the advantage to generating lift?
move freely up and down in the water column
What are the disadvantages to generating lift?
high energy expenditure
must maintain certain speed of movement
Who benefits most from generating lift?
How do you reduce dense materials for depth regulation?
reduce calcification of bones
reduce protein in muscles
increase in water
What is the advantage to reducing dense materials?
lift doesn't very with depth
What is the disadvantage to reducing dense materials?
Who benefits most from reduction of dense materials?
deep sea fishes
How does storage of fats/oils help with buoyancy?
squalene - low density hydrocarbon stored in liver of squaloid sharks
wax esters - coelacanth
lipids in bones
What is the advantage to storing oils/fats for buoyancy?
lift doesn't vary with depth
What are the disadvantages to storing oils/fats for buoyancy?
fine-tuning is difficult
buoyancy regulation linked to metabolism
What is a gas bladder/swim bladder?
gas-filled sac in upper part of body below vert. column and kidneys
storage of gas
What are the advantages of a swim bladder?
gas is light
precise control possible
no relationship to energy storage
many strategies possible
: sit and wait, slow cruising, hovering
: sound producer/detector
What are the disadvantages of a swimbladder?
lift varies with depth
large depth changes not practical over short time period
How is the swim bladder structured?
derived as outpocket of esophagus
physostomous - primitive (connect to esophagus through pneumatic duct)
physoclistous - advanced (closed, pneumatic duct sealed off)
What is Boyle's law?
at a constant temperature, volume varies inversely with absolute pressure
Pressure increases 1atm for every 10m in depth
What is the physostome solution for letting gas in/out?
secretion (gulp air) and burp
What is the disadvantage to the physostome solution?
fish dependent on surface if gulping air
What is the physoclistous solution for letting gas in/out?
resorption and secretion
How does resorption work?
removal of gases via blood
wall of swb not permeable - poorly vascularized, line with guanine crystals
use sphincter to regulate gas entering resorptive area
How does secretion work?
addition of gas - physostomous
diffusion of gases from blood in gas gland
: need high partial pressure/concentration of gas in blood
What are the 4 general ways to increase pp/concentration of gas in blood?
acidification releases O2 from hemoglobin (Bohr, Root)
Acid releases CO2 from bicarbonate in blood
Lactate and H ions reduce solubility of gases in aq. solutions - salting-out effect
efficiency of CCE (rete mirabile)
What is the Bohr effect?
reduced affinity of O2 under acidic conditions
slower loading of O2
What is the Root effect?
decreased capacity to bind O2 under acidic conditions
may never reach 100% saturation
Summary of secretion:
gas gland tiss. anaerobic resp -- Hi levels of lactate and H -- decreased pH
gas gland cells prod. CO2 combine with O2 -- carbonic acid -- lowers pH
low pH triggers Bohr/Root -- hemoglobin releases O2 into blood
Hi levels of plasma CO2 -- add. of CO2 into gas bladder
blood leaves gas gland via rete -- diffusible gases build up
pp of gas IN gg exceed pp in swb -- diffusion IN
What are the 3 main problems of breathing in water?
density (800x) and viscousity (50x)
solubility (decreases with increasing temp, salt/solutes)
*warm water has less O2 than cold water, and salt water has less O2 than freshwater
How do agnathans breathe?
intake water through nostril
ventilation pump (velum)
1-16 gill sacs with CC structure
How do elasmobranchs breathe?
intake through mouth and spiracle
ventilation (ram - mouth; pump - mouth & spiracle)
5-7 ext. gill slits (gill arch and ray, gill rakers)
How do teleosts breathe?
intake via mouth
ventilation (ram, pump)
continuous one way flow (water across gill filaments)
4 gill arches with rakers
What can occur when oxygen needs increase?
breathe more often
take bigger gulps
recruit more lamella
What does it mean to "recruit more lamellae"?
lamellae at tips rec. less water and blood flow
with increasing water flow, tips get flow
tips with more blood flow, higher blood pressure and dilation
What are the costs of breathing?
high density and viscousity = energy to ventilate!
branchial pumping = 10-15% energy
high vent volume = more costly
in humans cost is 2%
lower cost by ram breathing
What is ram breathing?
circumvents high cost of breathing when active
transfers work of vent. to locomotory musc.
seen in fishes in rapidly moving water
or actively swimming ocean fishes
What are the modifications/adaptations for fish who breathe air?
mod. gills - thick lamellae
mouth (vasc. buccal cav.)
gas bladders and "lungs"(allow survival in drought!)
Describe the pump system (circulation)?
4-chambered, single pump heart
sinus venosus (collects blood)
atrium (initial pump)
ventricle (main pump)
bulbus/conus arteriosus (elastic/muscular reservoir)
What is the general flow of blood in the circulatory system?
deoxy blood pumped directly to gills via ventral aorta and afferent branchial arteries
oxy blood from gills to body via efferent branchial art. and dorsal aorta
through musc. and organs then to heart via cardinal veins
How is oxygen transported?
hemoglobin (O2 carrying protein)
binds O2 at resp. surfaces, releases at tissues
sensitive to pH (Bohr), Temp (lower affinity with increasing temp)
What are two types of thermoregulation?
ectothermy - reliant upon external heat
endothermy - produce own heat
What are the advantages of being an ectotherm?
low metabolic costs (less E, less food)
What are the disadvantages of being an ectotherm?
cannot live/function well in extremes
What are the advantages to being an endotherm?
biochemical rxns become more efficient
fish can utilize wider thermal ranges
What are the disadvantages to being an endotherm?
high metabolic costs (req. more food, leaves less E for repro and growth)
What are 3 ways to conserve heat?
from rete near lg swimming musc
from rete on liver
CNS (circ. mod., special heat producing tissues)
What are the behavioral ways to cope with temp fluctuations?
move to locations with better thermal environment
What are the physiological ways to cope with temp. fluctuations?
switch genes on/off
increase enzyme concentration to compensate for reduced activity
isozymes (diff. gene loci producing enzymes that operate at diff. temps)
allozymes (alt. alleles at same locus that produce enzymes that operate at diff. temps)
mod. at cell/tissue level (sat/unsat fat ratio, # mitochondria)
What are the problems with high temperature evironments?
structural degradation of proteins
low O2 availability
What are the problems with low temperature environments?
slow biochemical rxns
intracellular ice crystals
What are the solutions to cold water env.?
FW - not a prob -- stay below ice
SW - supercooling (avoid crystal formation) or antifreeze (glycoproteins)
Where is blood filtered in the kidneys?
Where in the kidneys does resorption of ions take place?