Ichthyology Exam 2

fish ancestor

nonvertebrate chordate

non-vertebrate chordates have ____ shaped myomeres in postanal tail that have become ___ shaped for vertebrates

V, W

why are w shaped myomeres better than V

w shaped myomeres have more overlap givving vertical control with their tendons that contract one side at a time

how have fish changed from chordates to vertebrate

cranium moved anterior to notochord, dorsal nerve cord now protected by cartilage and bones, pharyngeal slits are now covered with muscle for respiration and supported by cartilage, V to W shaped myomeres on postanal tail

placodermi

extinct bony armored fish with jaws, heterocercal tail, dermal bony plates as “teeth”, craniovertebral joint

Acanthodii

extinct fish that didn’t fossilize good, median and paired spines, shark-like body, rhomboid platelets

surgeonfishes have a

scalpel

when s3x can be triggered to change, they are

hermaphrodites

Devonian stage

when all major modern fish lineages were present

cambrian

1st major period, early chordates, early fish-like vertebrates

parts of repro system

ovaries oviduct, testes and sperm ducts, cloaca, claspers (2 sex organs)

male repro organs

testes, sperm ducts, genital papilla (protrusion releasing sperm, claspers in chondrichtyes)

Ordovician

first jawless fish

silurian

first jawed fish

gonopodium

modified anal fin used for intenral fertilization (poecilid:guppies, mollies)

andropodium

modified anal fin to hold female during mating (not for sperm transfer)(goodeidae: split-fins)

female repro organs

ovaries (usually paired, sometimes fused, may be lobed or branched), oviducts, genital pore

sex roles in fish

gonochoristic (GSD and ESD enviro) or

hermaphrodites: simultaneuous hermaphrodites (protogyny is most popular), sequential hermaphrodites (most fish), maximizes fitness, survival, and repro success

simultaneous protogyny

is most popular simultaneous hermaphrodites, start as female then enviro/social cue makes them male

chromosomes of fish

ZZ male ZW female or XX XY

wide range vs narrow temperature tolerance range

eurythermal, sternothermal

HSF and HSP in thermal stress

heat shock induces expression of heat shock protein, HSP maintains structure of proteins bc if proteins denature the bio system shuts down

simultaneous hermaphrodites egg trading

both fish package eggs before repro, the acting “female” releases first and they take turns every few mins to externally fertilizes the others package

protogyny monandric vs diandric

only secondary males (born female), more susceptible to overharvesting of male bc they’re bigger

start as female and can either have small initial phase as male or female, then large terminal phase as male, aka they can be primary or secondary males

sequential protogyny

female has both germ cells, suppress female gonads to develop male ones

sequential protandrous

clownfish, less common, initially males that become females, larger size ranks you higher

fertility is higher with

protandrous than protogyny

temperature that fish lose equilibrium

critical thermal temperature

bi-directional sequential hermaphroditism

can switch back and forth, helpful for guppies who are very clustered

behavioral thermoregulation

fishes can find thermal refugias (salmon), deeper=colder (sharks)

sexual mating systems

monogamy (guppies, sea horses) biparental care, polygyny (gobiidae) male territory, polyandry (lampreys) 1 female and multiple males, promiscuity (smelts, clupeiformes) orgies, most common

climate change on fish distribution

cold water fish decline

endothermic fish retain/create heat by?examples of these fish

flapping pectoral fins, minimize heat loss through countercurrent heat exchange in gills, rete mirabile (network of veins/arteries), regional, sharks tunas opah

parthenogenesis

asexual mating “virgin birth”, endangered

gynogenesis, hybridogensis

unisexual mating, all females but sperm dependent, rely on presence of related bisexual species, male genes only get passed on for small time

the freezing point of __________ is higher than that of _________, fish can alter this with

fish blood, saltwater, glycoproteins

species that use antifreeze proteins

winter flounder, smelt, herring, notothenioid, arctic cod

polar fishes

high o2 saturation at low temps, antarctic icefishes have no RBC

ex of fish in extreme heat (hot springs), adaptations

desert pupfish, heat shock protein, paradoxical anaerobism, sensitive to enviro shifts

gynogenesis

no fertilization but does require presence of sperm, female only species, uses sperm of related species to trigger cloning development of mom

hybridogenesis

mothers own paternal genome discards and the other chromosome clones, females only species, first generation hybrid, ancient hybridization of monacha and lucida

what color are deep sea fishes usually

deep red or black, may be bioluminescent

what happens to light in water, longer wavelength light gets _____, the more _____ in the water, the more light is _____

scattering, absorption, reflection

absorbed faster

particles, scattered

o2 in water is called

dissolved oxygen

less o2 in water due to warming means

metabolic rates sped

low oxygen enviro fish (floodplain hypoxia or anoxic)

amazon fish- large gill area, air breathing, reduced activity

crussian carp- convert glycogen into ethanol for metabolic pathways, reduce energy demands, shut down vision and hearing

types of extreme habitats

low oxygen (anoxic, or floodpain hypoxia), deep sea (no light), extreme heat, freezing waters

Stenophagous

limited assortment of food types

Euryphagous vs Monophagous vs Stenophagous

mixed diet, one food type, limited assortment of food

feeding types

preds, grazers, browsers, scrapers, excavators, plankton feeders, suckers, parasites

types of plankton feeders

strainers (filtereres) herrings, anchovies, whale sharks

pickers (protrusible jaws) kelp perch, pipefishes

triangular model

opportunistic, equilibrium, periodic

oppurtunistic species mating

short gen time, small body size, lots of eggs and no parental care ex red shiners

digestive system organs

mouth, gill rakers, stomach, pylorica caeca, intestine

slimy groovy fish lips

toxic

thick tough fish lips

predators

thick fleshy, tactile with tastebuds, fish lips

bottom feeders

thin lips

planktivores

primitive vs advanced mouth bones

primitive- rigid, fused maxilla and premaxilla

advanced- separate maxina and highly protrusible premaxilla

forebrain

cerebrum (memory) and olfactory bulbs

midbrain

optic lobes and process input from ear and lateral line, least developed

hindbrain

cerebellum, some species use hindbrain to interpret electrical input, usually larger than human hindbrain relative to body size

what do fish use to hear

lateral line w modified scales and internal ear

lateral line system

canal neuromasts connected to nerves (sensory hair cells called cilia in gel structure)detect difference in membrane potential to send to midbrain, sense vibrations and pressure

sensitive superficial neuromasts are more concentrated on the head, sense local water movement, adipose fin

far-field vs near-field

lateral line uses near more, inner ear takes over more for far

_____ shaped vision

cone

fish vision hacks for fishing

wear dark colors, polarized sunglasses, block unwanted reflected ray by putting arm beneath chin, fish is deeper and closer than it looks

fish eyes

no eyelids

rods are more prevelant than cones in fish,

ex sharks only have rods, bony fish have more rods than colors, deeper fish have few cones since there’s less color with less darkness

taste and smell in fish

extremely sensitive, sensory folds in the nare, tastebuds on the body lips and mouth, chemoreception

species that esp use chemoreception

homing from coho salmon, dominance from catfish, detect spawning stream from sea lampreys, mating, predation

electroreception

not all fish, rely on ampullary organs and they have electric fields around them, chondrichthyes, colacanthiformes, ex, generate electric organ discharge and use tubular organs

magnetoreception

some fish like elasmobranchis, bony fish, sharks, long distance migration

nociception

ability to feel pain

sensory smog

overwhelming human caused pollution impact fish ability to navigate and mate

atlantic cod

able to grunt but humans are too loud now for grunting to help them

systematics

science of identifying relationships among groups of organisms

biological vs binomial nomenclaturew

formal system, genus species

naming committee of fish

AFS-ASIH

names honoring people are discouraged

true

physiological effects of temperature influences

metabolic rate, digestion, growth rate, reproduction

behavioral effects of temperature influences

activity level, feeding rate, migration patterns, distribution

range of heat tolerance

bell curve, zone of intertolerance and physiological stress when it gets too extreme

large vs narrow temperature range are called

eurythermal, stenothermal

fish most likely to tolerate rapid climate warming

A. Cold-water dependent Arctic char
B. Temperature-generalist carp
C. Hydrothermal vent snailfish
D. Stenothermal deep-sea anglerfish

Many deep‑sea fish have enlarged eyes or tubular eyes
primarily to..

maximize light capture

higher temps leads to ____ salinity, ____ dissolved oxygen

higher, less

agitation temperature

fish can be in it but they show avoidance behaviors

freezing point of saltwater compared to fish blood

-1.9 C, 0 C

what do antifreeze proteins due to fish blood

lower freezing point past -1.9 C so they freeze after saltwater does

polar fish adaptations

AFP, high oxygen saturation, no RBC (antarctic icefish)

lighting changes cause

effects on food web, impact primary producers, light at night causes food chain reaction

most deep fish are

predators or scavengers

adaptations for fish in extreme deep pressures

soft gelatinous tissue, compressed bodies, TMAO proteins support other proteins, no gas bladder or physoclistous

adaptations in total dark caves

loss of pigmentation and eyes, enhanced senses, altered metabolism, genetic changes to sleep and still have circadian rhythms

global deoxygenation

reduced solubility in warm waters, stratification, speeds metabolic rate

floodpain hypoxia fish adaptations, and ex of type of fish

large gill surface area, air breathing, reduced activity, amazon fish

adaptations of fish in anoxic waters

convert glycogen to ethanol for metabolic pathways, reduce energy demands, shutdown vision and hearing

early polluck survival

sudden increase hen drop due to low fat diets maybe

most fish are ____ ____ feeders

oppurtunistic suction