Exam 2 Flashcards
What is the most primitive living vertebrate?
hagfish
What do marine organisms get more of in comparison to freshwater organisms?
electrolytes
Do hagfish have jaws?
no, they are jawless
Since hagfish have no jaws how do they go about feeding?
they have keratinized teeth that rasps tissues and a muscular tongue
What does a hagfish primarily eat?
dead or dying fish
What is a hagfish also known to eat besides dead or dying fish?
marine worms and crustaceans on the ocean floor
What is a hagfish’s mouth surrounded by and what are they used for?
tentacles, they are used for touch
Why do hagfish have tentacles for touch instead of relying on their eyesight?
they have degenerate eyes that are covered by thick skin, this makes them have a keen sense of smell and touch
How many gill slits do hagfish typically have?
multiple, however other species can have over 10 pairs on each side
Do hagfish have a primitive lateral line system?
yes
What kind of kidneys do hagfish retain into adulthood?
primitive kidneys “pronephros”
What are primitive kidneys?
they are kidneys normally only seen in embryonic development
Hagfish are isosmotic, what does this mean?
its osmolarity is the same as its environment
What environment does a hagfish live in?
marine environments (saltwater)
What is osmosis?
diffusion of water though a semipermeable membrane
What does the word “osmolarity” refer to?
the number of solute particles in a fluid
What is osmotic pressure?
the pressure that is required to stop osmosis
What is the osmolarity of sea water?
1000 mOsm
What is the osmolarity of freshwater?
20 mOsm
What is the osmolarity of mammals body fluids?
300 mOsm
What other organisms are also isosmotic?
the protochordates (tunicates and amphioxus)
Are invertebrates isosmotic?
yes
What is the purpose of the hagfish’s accessory hearts?
They are in the venous system and help pump blood back to the main heart
What does the body of a hagfish have and produce?
their bodies have slime glands that open to the outside of the body through many pores
What is the purpose of the large amounts of slime produced by hagfish?
it is a defense mechanism
What are hagfish known as to fisherman?
slime eels
What is the hagfish’s knotting behavior used for?
rid themselves of slime, also to gain traction while eating or trying to flee predators
Where do all hagfish dwell in the ocean?
they are bottom dwellers in relatively deep waters (300 ft or more)
What is the sexual reproductive system of a hagfish?
they have a single long gonad and non reproductive ducts
What kind of fertilization is present in hagfish and how does it work?
external fertilization: gametes are given off into body cavity and then exit through a pair of genital pores into the cloaca
Is there a larval stage in the hagfish?
no
Is there an economic significance to hagfish?
yes, their meat is eaten in some parts of the world and their skin is used to produce “eel skin” for leather goods
How many pair of gills and gill opening do lampreys have?
7 pairs
What is the lampreys one nostril used for?
olfaction
What is well developed in a lamprey?
their eyes and their lateral line system
Do lampreys have accessory hearts?
no
What is the osmolarity of a lampreys body?
approx. 300 mOsm
Do lampreys have well developed kidneys and ion pumps on gills?
yes
Lampreys are _______ to seawater and ________ to freshwater.
hypo-osmotic; hyper-osmotic
Do lampreys live in marine water or freshwater?
they’re anadromous, they live in marine water and travel to freshwater to reproduce
How many species of the lamprey are parasitic?
18 species
How do lampreys feed?
sucker life mouth with keratinized teeth and tongue with teeth, they attach by suction and use teeth to rasp skin away
What do parasitic lampreys secrete”
anticoagulant
Non parasitic lampreys have what kind of digestive tract?
degenerate; so as adults they don’t feed
How long do non parasitic lampreys live?
only a few months
What do lamprey eggs develop into?
ammocoete larva, meaning it is distinctly different from the adult body form
What do ammocoetes do through their long larval stage?
dig into the bottom of streams and filter feed
How long may ammocoete larva feed before they undergo metamorphosis into an adult lamprey?
3 to over 8 years
How long do parasitic lampreys feed before reproducing?
1-3 years
What happens to anadromous forms of the lamprey?
adults migrate to freshwater to spawning and die soon after spawning
When do non parasitic lampreys breed?
soon after metamorphosis and then die
Can some species of lamprey live entire life in freshwater? what is an example?
yes; lamprey in the great lakes
How are lampreys of economic importance?
they negatively impact, they get rid of and eat other important fish
When do the first jawed fish appear in the fossil record?
silurian period
What did the development of jaws to for feeding capabilities?
increased them and allowed for new food sources
What else did jaws allow for?
new behaviors such as digging of nests
How do embryological and anatomical studies suggest that jaws may have developed?
through modification of several sets of anterior gill arches
What did early jaws fish also have and what was its function?
paired fins which enhanced their ability to control their movements and allows them to better use their jaws
What are the two earliest groups of jawed fishes?
acanthodians and placorderms
Describe Acanthodians.
appear to be first jawed fish in fossil record
name refers to their stout spine
structurally appear to be related to modern fish
Describe Placoderms.
appear slightly later than acanthodians
body covered with thick bony shields
When were both Acanthodians and Placoderms flourishing and when did they decline and become extinct?
Devonian; Carboniferous and Permian
What animals are in the class Chondrichthyes?
sharks, skates, rays, chimeras
What animals are in the class Elasmobranchs?
sharks, skates, and rays
When do the fossils of early shark like Chondrichthyes date back to?
late silurian and the Devonian period
What is an example of the early shark like Condrichthyes?
Cladoselache
When did Cladoselache become extinct?
during the carboniferous
Chondrichthyes was the first jawed fishes with what kind of skeleton?
cartilaginous
What kind of tail do sharks have?
heterocercal
What kind of scales does the class Chondrichthyes have?
placoid, however chimeras have no scales
What do placoid scales help with?
reduce turbulence when swimming
What do the mucous glands in class Chondrichthyes help with?
prevent abrasions, infections, decrease predation, and decrease drag while swimming
How are sharks usually identified?
by their tooth structure, because teeth are species and genus specific
Are jaws firmly attached to the cranium in Chondrichthyes?
no, except in the chimera
Why are the jaws not attached to the cranium in class Chondrichtyes?
so they can be extended when feeding
Can sharks swallow prey whole?
yes, they can even be known to attack whales
Does class Chondrichthyes have a gas bladder?
no
How can the gas Chondrichthyes have buoyancy with no gas bladder?
their buoyancy is aided by large amounts of oil in the liver (squalene oil)
What percent of Chondrichthyes body weight is the liver? What percent of the weight of the liver is attributed to oil?
25%; 80%
What are the differentiated lobes in the brains of Chondrichthyes?
olfactory, optic, cerebrum, and cerebellum
How many cranial nerves do Chondrichthyes have?
10 pairs
How many loops does condrichthyes semicircular canals have?
3
Chondrichthyes has well developed what?
olfaction and lateral line system
What is the Ampullae of Lorenzini?
electroreceptors on the nose of Chondrichthyes
What kind of changes do the Ampullae of Lorenzini detect?
temperature changes
What kind of feeders are sharks?
nocturnal feeders
How do shark eyes work in low light?
mirror like layer behind the retina to reflect light and enhance vision; their lens also moves back and forth to focus on objects at different distances
What is the sharks additional eyelid called?
nictitating membrane
What does Chrondichthyes digestive system have?
stomach, liver, gall bladder, pancreas, and large spiral valve in intestines
What is the function of the spiral valve?
slows the passage of food and increases surface area available for digestion
What kind of heart does Chondrichthyes have?
2 chambered heart
How is blood pumped through the body of Chondrichthyes?
from heart to gills then to the body; its a low pressure system
What is the function of the rectal gland?
secretes concentrated salt solution into cloaca, helps regulate proper salt concentration in blood and body fluids
Are sharks isosmotic to sea water? if so what is their osmolarity?
yes, 1000 mOsm
Describe the reproductive system of Chrondrichthyes.
gonochoristic
have paired gonads and reproductive ducts
ducts connect to cloaca (except in holocephali)
What is the function of the cloaca in Chondrichthyes?
chamber that receives material from the urinary , digestive, and reproductive system
What allows for internal fertilization on sharks?
claspers
What is oviparous?
embryo & nutrients are sealed in an egg case and released into the water
What is an egg case made out of?
keratin
How long does it take for an egg to hatch?
6 months to over a year
What is ovoviviparous?
embryo & nutrients are deposited in the oviducts and can be surrounded by a thin egg case; develops within mother and is “born”
How long does it take an egg to hatch in the mother?
9 months to well over a year
What is viviparous?
direct connection between mother and embryo; embryo and yolk are deposited in oviducts, embryo also receives nutrients via blood vessel in yolk sac (primitive placenta)
How long does a placenta attached embryo take to be born in a mother?
8 months to well over a year
Is shark meat a popular good in some areas of the world and even in the U.S.?
yes
What is skate and stingray meat sold as?
“scallop” meat because it has a similar taste and texture
What is shark finning?
catching sharks for fins while throwing away the rest of the body
Is shark skin used for leather?
yes
Shark liver oil has be sold as a health supplement, why?
rich in vitamin A and has a variety of “unsubstantiated” health benefits
What are shark populations susceptible to and why?
excess commercial fishing because they are slow growing and slow to mature
What is an example of shark that has been overfished?
the porbeagle shark in western North Atlantic
Why are there laws that regulate the number of shark species that can be captured each year?
in order to maintain “maximum sustainable yields” of each catch
What animals are in Holocephali?
chimeras (ratfish or rabbitfish)
What are the physical characteristics of chimeras?
fish like body with long flexible tail
large venomous spine of the first dorsal fin
large eyes
What are the function of chimeras large eyes?
help vision in dim light, possible seeing bioluminescent organisms
What are chimeras considered to be condrichthyes?
they have a cartilaginous skeleton, spiral valve, oil filled liver, and claspers in males
What are the differences between chimeras and sharks, skates, and rays?
upper jaw is firmly attached to the skull
single gill flap, no spiracle
no scales
no cloaca (they have separate openings for reproductive, urinary, and digestive systems)
Where to chimeras inhabit?
marine waters and typically deep and offshore
What do chimeras feed on?
mainly shellfish and other invertebrates
What do chimeras have that help them crush shellfish?
plate like teeth
How do chimeras reproduce?
they are oviparous, their young develop in egg cases that are deposited on the bottom
What is the class of Elasmobranchs divided into?
Batoids (55% of species)
sharks (45% of species)
How are batons thought to be derived?
from shark like ancestors
When are the earliest fossils of batoid found?
the jurassic period; relatively recent in comparison to shark like condrichthians
What is the general morphology of Batoids?
body flattened dorsoventrally
enlarged pectoral fins (used for swimming)
spiracle on dorsal surface & gill slits on ventral surface
reduced tails or tail spines with venom
plate like teeth for crushing prey
Where do Batoids look for prey?
on the bottom of the ocean floor
How does the spiracle work in species which lay on the bottom of the ocean floor?
water is taken through the spiracle and pushed out of the ventral gill slits
In what kind of water do Batoids inhabit?
most are marine, but some ‘euryhaline’ can travel into freshwater
Since most Batoids are bottom dwellers what behavior do they exhibit?
often bury themselves in the bottom sand
What do most Batoids feed on?
crustaceans, mollusks, and other invertebrates found on the bottom
What are examples of the diversity in batons?
guitar fish
saw fish
skates
rays
Describe the guitar fish.
intermediate between skates and rays
propels itself with tail
spiracle on dorsal surface, gill slits on ventral
uses snout to burrow while looking for food
contains electroreceptors
What do guitar fish feed on?
mollusks, crustaceans, worms, and fish
How do guitar fish reproduce?
ovoviviparous (produce live young)
In what habitat are guitar fish found in?
shallow coastal waters and up into estuaries; and possibly rivers
Describe sawfish.
spiracle dorsally, gill slits ventrally
similar shape to guitar fish
teeth are modified placoid scales
contains electroreceptors
How can a sawfish use its “saw”?
slash through schools of small fish to stun prey and break up the schools
stir up bottom to uncover prey
defend itself against predators
Where do sawfish primarily inhabit?
marine environments but some are found in freshwater (euryhaline)
How do sawfish reproduce and what’s a detail about the babies?
they’re ovoviviparous; teeth on saw of baby is covered with skin to prevent damage to the mother
Are all species of saw fish endangered?
yes
What was the first marine fish to be put on the endangered species list in the U.S.?
saw fish
Describe skates.
ventral gill slits
dorsal fins near tip of tail & thorn like spines along back and tail (no long sharp spine)
What do skates feed on?
feed on invertebrates on the bottom
How do skates reproduce?
oviparous and produce eggs (mermaids purse eggs)
What is the most abundant skate in Alabama?
clearnose skate
Where are sawfish reported to live?
Gulf of Mexico & Atlantic waters of U.S.
freshwater lake Nicaragua
rivers in Australia
Describe rays.
whip like tail
dorsoventrally flattened
How do rays reproduce?
ovoviviparous
What do rays feed on?
most feed on invertebrates on the bottom
What is an example of a ray?
stingrays
bluntnose, Atlantic, and southern
eagle ray
cownose ray
manta ray
electric rays
Do all rays have spines?
no just stingrays
Where are bluntnose, Atlantic, and southern stingrays found?
coastal waters of Alabama often living on the bottom
What rays are examples of ones that swim in the water column in big groups looking for mollusks and crustaceans?
eagle rays and cow nose rays
What are manta rays also known as?
the devil ray; from its appearance of its cephalic fins when rolled up
What do manta rays feed on?
filter feeder planktons
What kind of mouth does a manta ray have?
terminal mouth (front of head)
How do cephalic fins help manta rays?
help guide food into mouth as manta slowly swims near oceans surface
Where do manta rays migrate?
through tropical and temperate oceans looking for plankton rich waters, sometimes migrate in large groups
What is the largest group of rays as well as batoid?
the manta ray
Why do manta rays breach high out of water?
mate attraction
play behavior
ridding itself of parasites
How do manta rays reproduce?
ovoviviparous
Describe electric rays.
flattened body
well developed tail
electric organ located on side of the body
Describe an electric ray’s electric organ.
connected to brain via large nerves
composed of specialized muscle cells that act as series of batteries and generate action potentials
can generate 220 volts or more
used to deter predators and sun pray
What do electric rays feed on?
shellfish they are bottom dwellers
How do electric rays reproduce?
ovoviviparous
What are examples of electric rays?
Torpedo ray
Lesser electric ray
What is the largest electric ray, up to 220 volts?
torpedo ray
Where can torpedo rays be found?
along the Atlantic and pacific coasts of U.S., sometimes the gulf of Mexico
Where can you find the lesser electric ray?
found in Gulf of Mexico and Atlantic, including coast of alabama
How large of a shock can a lesser electric ray produce?
approx 35 volts
What are examples of the diversity in sharks?
nurse shark
thresher shark
great white
tiger shark
hammerhead shark
whale shark
bull shark
Describe the nurse shark.
shallow water, bottom dwelling shark
rests on bottom and feeds on invertebrates & small fish
has barbels extending from nasal opening
example of shark that is harmless to humans
Where is the nurse shark commonly foudn?
atlantic, carribean, and gulf of mexico
How do nurse shark reproduce?
ovoviviparous with development occurring in a thing shelled egg, egg is retained in mothers oviduct until hatching
Describe the thresher shark.
extremely long tail (longer than body)
strong swimmer, known to breach out of water
How do thresher sharks use their tails?
“herds” through schools of fish and to stun prey
name comes from the whip like use of its tail
What do thresher sharks feed on?
fish and squid
Where are thresher sharks in the world?
world wide distribution including Gulf of Mexico
can also occur in warm and cold water
How do thresher sharks reproduce?
ovoviviparous, example of omophagous shark
embryos may eat unfertilized eggs in the oviduct
What does oophagous mean?
egg eating
What is a great white also known as?
white pointer because of white bottom and pointed snout
What is the largest living predatory shark?
great white
What do great whites feed on?
small and large prey
well known for feeding on pinnipeds (seal, sea lions)
other sharks, fish, and sea turtles
What are great whites well known for?
attacking humans and account for more fatal shark attacks on humans than any other species of shark
Where are great whites found?
world wide, normally offshore but can be found near shore
normally in cold waters (southern Australia, N.E. U.S., W coast of U.S., Gulf of Mexico)
Why have some great whites been recorded migrating thousands of miles?
for feeding and breeding purposes
ex. california > hawaii; South Africa> Australia
How do great whites reproduce?
ovoviviparous and are oophagous
Carcharodon megaladon is an extinct relative of what shark?
the great white (same genus)
What does megaladon mean?
mega tooth
When did the megalodon exist?
about 20 million years ago, became extinct about 3.6 million years ago
Describe tiger sharks.
young have obvious stripes that fade with age
blunt snout
voracious eater
more dangerous relative to humans
What do tiger sharks eat?
variety of prey including; fish, sea turtles, marine mammals, humans, sometimes also trash
Why are tiger sharks more dangerous to humans?
normally inhabit warmer ocean water and will frequently move into shallow waters
How do tiger sharks reproduce and how large are their litters?
ovoviviparous and 20-40 pups
Where can tiger sharks be found?
gulf of Mexico
Describe hammerhead sharks.
flattened head
warm temperate shark
known to aggregate into large schools in certain areas
How does a flattened head help the hammerhead shark?
enhances its vision and olfaction
enhanced depth perception and peripheral vision
advantageous while swimming (enhances movements)
Are hammerhead sharks known to attack humans?
yes
Where are hammerhead sharks common?
gulf of mexico
How do hammerhead sharks reproduce?
viviparous, connection between mother and embryo; can have 20 or more pups in a litte r
What is the largest living fish?
the whale shark
Describe the whale shark.
dark body with white spots
pelagic feeder that swims slowly near the surface
sometimes forms schools
What do whale sharks feed on?
crustaceans, schools of squid, and small fish
How do whale sharks reproduce?
ovoviviparous
Where are whale sharks found?
throughout tropical and subtropical oceans including gulf of mexico
Historically what are whale sharks harvested for?
meat, fins, and oil but are currently a protected species in most of the world
Where are bull sharks common?
gulf of mexico, but occur worldwide
Bull sharks are an example of a euryhaline shark, what does this mean?
known to travel up rivers
Where else do bull sharks inhabit?
Mississippi River
amazon river
lake Nicaragua
Why is Osteichthyes a paraphyletic group?
because it does not include tetrapods
What kind of ancient fish appear most similar to the bony fishes?
acanthodians
What are acanthodians?
first early groups of jawed fish from the silurian period
What are the 2 basic groups of bony fish?
Actinopterygii and Sarcopterygii
What are the general characteristics of actinopterygii and sarcopterygii?
bony skeletons
dermal scales
When did the first bone appear in fish?
jawless fish (ostracoderms) and some early jawed fish (placoderms and acanthodians)
What are the important functions of bone?
allows for strong skeleton to support the body and muscle attachments
protection of brain and spinal cord
provides location for calcium storage
What are the 3 types of scales found on bony fish?
ganoid, cycloid, and ctenoid
Where are ganoid scales found?
relatively primitive bony fish (bichir, sturgeon, paddlefish, gar)
Describe ganoid scales.
thick compared to cycloid and ctenoid
don’t overlap one another
What scales are found on more advanced fish (teleosts)?
cycloid and ctenoid
Describe cycloid and ctenoid scales.
thinner and lighter
overlap
provide protection and flexibility
ctenoid scales have small spines to help dcrease drag
What is the function of mucous glands in the skin?
locate epidermis covering scale
makes it difficult for predators to grasp fish
decreases resistance of fish in water as it swims
acts as protective barrier to prevent infections
What would be considered strongly electric?
anything that can shock something else
What are bony fish also known as?
Osteichthyes
How many species of sharks are there?
500
How many species of batoids are there?
600
How many species of jawed bony fish are there?
28,000 species
What is the advantage of cycloid and ctenoid scales?
thinner
flexible
overlapping for strength
What is the advantage of having the little bumps on the ctenoid scales?
less drag and makes them faster
Where are scales located on a fish?
in the dermis
What is another function of mucous?
can form “shells” around fish to camouflage their smell
Where are chromatophores located in fish?
in the dermis of the skin
Is the color obvious or not obvious when pigments are dispersed throughout the chromatophore?
the color is obvious
Is the color obvious or not obvious if the segments are concentrated in the middle of the chromatophore?
the color is not obvious
What is the purpose of iridophores?
type of chromatophore that acts as mirror cells, shiny and able to confuse other fish
Why is color important to fishes?
concealment and disguise
advertisment
mimicry
What is concealment and disguise used for?
they do not want to be noticed by predators or prey
What is advertisement used for?
they want to be noticed for species and mate recognition, or for territorial behavior
What is mimicry used for?
may have coloration that confuses other species
What is an example of mimicry?
some fish have false eyespots
Do fleshy or lobe fins contain bone or muscle (maybe even rays)?
yes
Are ray finned fishes fins only supported by rays?
yes
What are rays composed of?
keratin and/or bone
What do rays in some fish contain?
have toxin glands at their base and venom that can be injected
What are example of ray finned fish with toxins and venom?
stonefish
scorpion fish
lion fish
Can lion fish be found in the United States?
yes
What do changes in fin structure in bony fishes allow for?
more precise, agile, and variable movements
What can happen for fine control of fin movement?
rays can be controlled by different muscles in the fin
What are the different types of caudal fin tails?
homocercal
heterocercal
diphycercal
What kind of tails do most modern fish have?
homocercal tails
What kind of tails do most primitive fish have?
heterocercal tails
What do heterocercal tails provide?
thrust forward and lift
What are the jaws of bony fishes adapted for?
quick explosive movements
What are shark jaws adapted for?
crushing and tearing food
What are the jaws of bony fish set up for?
to create suction
What are characteristics of well developed gills?
large surface area and good vascularization
Why are gills highly vascularized?
efficient for extracting oxygen from water
What are gills protected by and what is its function?
operculum; helps pump water over the gills
What kind of hearts do bony fish have?
2 chambered; pumps blood to gills them to body (low pressure system)
What do fish lungs appear to be?
outcroppings of the gut
What is present in some groups of primitive bony fish (lungfish, etc)?
lungs
How are lungs used in fish?
as accessory organs alongside the gills
Fish lungs appear to be homologous to lungs in what group of animals?
more advanced vertebrate
What kind of breathers are lungfish?
positive pressure breathers (force air down)
What is the gas bladder thought to have been developed from?
primitive fish lungs
Define physostome.
fish that have a duct connecting esophagus to gas bladder (gulp air); in many primitive fish
Define physoclistous.
fish that don’t have the connecting duct; most teleost fish
What is the function of the gas gland and the ovale?
puts gas in; takes gas out
In what kind of fish are gas glands in?
physoclists
Where is the oval body located in fish?
attached to gas bladder; acts as safety valve
What is an additional function of the gas bladder?
sound detection, picks up vibrations
What is the Weberian ossicle?
small bone that transfers sound from gas bladder to the inner ear
Do fish have an inner, middle, and outer ear?
no only an inner ear
Can the gas bladder be used to produce sound in some fish?
yes
Why is sound important to some fish?
territorial behavior
mate identification
mating behavior
startle response
How many cranial nerves of fish have?
10 pairs
How many inner loops do fish have on each semicircular canal?
3
What do some bony fish have in their skin that detects electrical current?
electrical receptors
What are electrical organs in some fish made from?
modified muscle tissue
What do strongly electric fish use their electricity for?
for stunning prey or predators
How many volts can an electric catfish produce?
300 volts; found in African river basins
How many volts can an electric eel produce?
over 600 volts; found in South American river basins
How do weakly electric fish use electricity?
as sensory information, they generate an electric field around their bodies
What can the electric field in fish be used for?
mate ID and selection; each species has distinct electric fields
Is a knife fish a weakly electric fish or strongly electric?
weakly
How do most bony fish reproduce?
they are mostly gonochoristic and use external fertilization
What do bony fish typically have?
high fecundity; can produce 100,000 or more eggs in a lifetime
What is a simultaneous hermaphrodite?
where fish are both sexes at once
What is a sequential hermaphrodite?
changes sex during their lifetime
What is protogynous?
change from female to male
What is an example of a protogynous fish?
bluehead wrasse
What is protandrous?
change from male to female
What is an example of a protandrous fish?
anemone fish
Define high fecundity.
high offspring yield within the lifetime of the fish
What is the latest all 3 groups of sarcopterygian fish date back to?
the devonian period (the age of fishes)
What were the Rhipidistia?
extinct group of sarcopterygii; fleshy finned and appear closely related to early tetrapods
What is a well known group of Rhipidistians?
Osteolepiforms
What are the 2 living forms of sarcopterygii?
lungfish and ceolocanth
What kind of tail do lungfish have?
diphycercal tail
What kind of scales do Australian lungfish have?
thick bony scales
What kind of scales do african and south american lungfish have?
small soft scales
Why was one species of lungfish initially classified as a reptile?
due to the advanced structure of their lungs
Why was a second species of lungfish initially classified as an amphibian?
due to the advanced structure of the heart
The gills in african and South American lungfish are _______ in adults.
reduced
Lungfishes lungs have what in comparison to gas bladders?
surface area and vascularization
How do lungfish get air?
they go up to the waters surface and gasp air
What kind of heart do lungfish have?
2 chambered heart, partial walls in atrium and ventricle that begins to separate oxygenated and deoxygenated blood
Where do all living lungfish live?
freshwater
rivers
lakes
swamps
What do lungfish eat?
invertebrates
fish
amphibians
Do lungfish have a spiral valve?
yes
How do lungfish reproduce?
have separate sexes and use external fertilization
What are the 3 living lungfish?
australian
african
South American
What is the most primitive of all lungfish?
the Australian lungfish
What are the characteristics of the australian lungfish?
large stout body
fleshy fines
well developed lungs & gills
How long can an australian lungfish live?
50 years or more
What kind of breather is the australian lungfish?
facultative air breather; relies on gills for respiration & the uses lungs when necessary to supplement its need for oxygen
The Australian lungfish can survive in _______ but can’t live without water.
stagnant, oxygen poor water
How many species of african lungfish are there?
4 species
What kinds of bodies do the african & South American lungfish have?
narrow elongated bodies with long narrow pelvic and pectoral fins (no fleshy fins)
African and south american lungfish are obligate breathers, what does this mean?
as adults they have reduced gills and need to breath air to live & can survive out of water for prolonged periods of time
Define aestivate.
similar to hibernation with decreased metabolic rate that lower oxygen consumption (however continues to breathe air)
How does the african lungfish aestivate?
burrows down into a pond or stream in dry season and forms a cocoon around itself with mucous and mud
What does urea build up in the body of lungfish do during aestivation?
acts osmotically to decrease evaporation from the lungs
When do lungfish typically break out of their cocoon?
about 6 months later, some can last up to 4 years
What are ceolocanths?
group of lobe fin fish, many extinct species date back to Devonian
How many species of ceolocanths have been found in the fossil record?
120
When was the first live ceolocanth discovered after being thought to be extinct for millions of years?
1938
Who discovered the thought to be extinct ceolocanth in 1938?
marjorie Courtenay Latimer
When was the next ceolocanth captured after 1938?
1952
here are coelacanths periodically captured?
waters off east and south coast of Africa
When and where was a second species of ceolocanth captured?
1998 in Indonesia 6200 miles east of african waters
What are the primitive characteristics seen in the ceolocanth?
lobe fins
spiral valve
diphycercal tail
thick bony “cosmoid” scales
Where do ceolocanths typically live?
relatively deep water
What is the ceolocanth said to be?
the missing link between fish and amphibians
What groupd of extinct fish are more closely related to early amphibians?
rhipidistia
What are the primitive ray finned fish?
chondrostei and bicher
What 2 groups are neopterygii split into?
primitve neopterygians
teleostei
What are the 3 groups of primitive ray finned fish?
bichir
sturgeon
paddlefish
Why is the bichir sometimes classified in its own group?
because it is somewhat unique
What is the bichir also known as?
flagon fish or african reedfish
Where are bichir found?
african rivers, lakes, and swamps
What is the most primitive living member of actinopterygii?
the bichir
What are bichir similar to?
palaeoniscid fish (early actinopterygii from the Devonian)
What are characteristics of the bichir?
bone skeleton
ganoid scales
abbreviated heterocercal
paired lunglike gas bladder
physostome
spiral valve
fleshy lobe like pectoral fins
What do bichir feed on?
invertebrates and small fish
Where do the 2 living species of paddlefish live?
rivers and streams
What are the primitive characteristics in paddlefish?
cartilaginous skeleton
lung like gas bladder
heterocercal tail
ganoid scales (on tail)
spiral valve
Do paddlefish have scales?
no only a few on the tail
What is an obvious characteristic of the paddlefish?
its large paddle like snout
What is the large paddle like snout of the paddlefish used for?
sensory organ, contains ampullae for detecting electric fields; can also detect water that is heavily laden with plankton
What do paddlefish feed on?
plankton (filter feeds)
Where are both species of paddlefish found?
- north America
- Yangtze River in china
What do sturgeon have along the sides and back of its body?
scutes or shields
What kind of mouth does a sturgeon have?
subterminal mouth; extendible & is used to suction feed of invertebrates
What do sturgeons have that are used for touch for finding food on the bottom?
barbels
What primitive characteristics do sturgeons have?
cartilaginous skeleton
physostome
heterocercal tail with few ganoid scales
spiral valve
How long of a life span can sturgeons have?
50-100 years
Where do sturgeons inhabit?
both freshwater and marine (anadromous)
Where do sturgeon breed?
freshwater
What are sturgeon famous for?
caviar or “salted roe”
What does Beluga refers to?
a species of sturgeon that lives in the caspian and black seas
What is the largest species of sturgeon?
beluga; its eggs are used for beluga caviar
How old was the oldest beluga sturgeon?
118 years
Where does the gulf sturgeon inhabit?
coast along the gulf of mexico including alabama; travels up rivers to spawn
What is the gulf sturgeon listed as by the U.S. fish and wildlife service?
threatened
What fish is a protected species in AL?
the gulf sturgeon
What was the largest recorded fish from freshwater in AL?
gulf sturgeon 9.5 ft, 400 lbs in 1924 coosa river
Where does the alabama sturgeon occur?
some rivers of central and southern AL
What is one of the rarest freshwater fish in the U.S. & is listed as an endangered species?
alabama sturgeon
Why is the alabama sturgeon an endangered species?
habitat loss
fragmentation (due to dams)
overfishing
decreased water quality
