Sharks Exam 3 Flashcards
Are bull sharks euryhaline or stenohaline?
euryhaline
What allows the bull shark to live in freshwater?
high ion concentration
What controls osmoregulation?
kidney, gut, skin, gills and rectal gland(digitform)
They act as barrier and allow movement of water and ion
How much nitrogen do they take in?
More than they need. Must excrete excess nitrogen. some as urea
Where is nitrogen excreted?
kidney or gills
How is some reabsorded?
active transport
What does a build up of urea in the body do?
regulates osmolarity
What problem does this create and how is it fixed?
it is damaging to tissue.
They manufacture and store TMAO-trimethylamineoxide, it stables protein and prevents damage.
WHy are sharks slightly hyperosmotic?
They have higher urea in muscle and body TMAO
What is hyperosmotic vs hypoosmotic?
hyper is higher, hypo is lower
What does the rectal gland do?
Removes salt from body and dumps into lumen
WHat is in the rectal gland?
chloride cells
Where does most of the urine go?
accessary urinary duct
What kind of kidney do they have?
opisthonephric kidney
Where does the glomerulus lie?
renal capsule-fluid leaks out of the capsule
What is the excretory duct?
eprinecetric duct
Why do sharks have long tubes?
to have a higher concentration of urine
What is in seamen?
spermatozoa and other stuff.
What is sperm?
spermatozoa
Lake Nicaguara bulls have high output of?
urine
WHere is salt lost at?
gills-more salt than water
What direction do chloride cells work?
Opposite direction-brings salt in via ATP pump
What is different about Nicaguara bulls?
They have reduced rectal glands. THey don’t want to get rid of salt.
What are marine sharks to seawater?
slightly hyperosmotic
In marine sharks, Is sodium chloride higher or lower than seawater?
lower than seawater
Are inorganic salts higher or lower than seawater? WHat are they?
Lower - mg, so4
1/3 of seawater level
Where does water enter the shark?
gills and food
WHere does water leave?
Lots of water excreted through the kidney
Was size is the glomerulus in marine sharks?
large
Where does sodium chloride enter and exit?
Enters through the gills and food
Exits through the rectal gland
What is the freshwater ray in the Amazon river?
Potamytrygonidae
What size rectal gland do the Amazon Ray have?
small, don’t concentrate urea, but excrete lots of it
Are the Amazon rays hyperosmotic?
yes
What are the gills part of?
visceral skeleton and are supported by the branchial arteries
Where do the afferent arteries go?
bronachial arteries go toward the gills
Where do the efferent arteries go?
bronchial arteries go away from the gills
Elasmobranchs have what kind of gills?
septal
What are the gills made of?
cartilage
How many gills slit and cartilages?
5 gills slits and 4 cartilages
What is a hemibranch vs holobranch?
hemibranch is one side
homobranch is both sides
4 holobranchs with one extra himeibranch
What is the purpose of the gill rakers?
keeps debris out of the gills, gills soft and bleed easy
How do Jacks kill sharks?
repeatedly hit the gills and make them bleed out
What are in dogfish and whale sharks spiracle?
pseudobranchs-small amount of gill tissue
Where does the spiracle get blood from?
efferent side an then goes to the eye, may help oxygenate the eye
Do lemon sharks have a spiracle?
no
DO ray and skates have spiracle?
large one, take in water and release it through the gill slits
How do white, basking and mako sharks breath?
ram ventilation, no correlation between ram ventilation and ram feeding
What other forms of ventilation are there?
force suction/buchal pumping ex white tip and nurse
Can nurse sharks tolerate hypoxia?
maybe
How do carribean reef sharks ventilate?
ram and force
What is the purpose of the secondary lamellae?
increases surface area
WHat does the secondary lamellae have in the epithelium?
basement membrane
WHat holds up the basement layer?
pilaster cells, pillar
How do the blood and water run?
countercurrent
What supplies blood to the secondary lamellae?
afferent arteriolar first to the secondary lamellae then to the efferent arteriole
where does the gas exchange occur?
secondary lamellae
WHat else occurs at the gills?
ion exchange, have special cell between secondary lamellae
Why do we study reproduction?
conservation, embryology and fish farming
What produces the eggs?
ovary-can be single or paired ovary
what is the additional function of the ovaries?
produce hormones
How many ovaries do Carcharhinus have?
one large may have vestiges of left
What do the eggs look like?
May be large and yolky
How is nutrient intake he in pups completed?
gills- some have yolk sac exchange
How pups do Squalus have?
dogfish have 2
What is the general vertebrate condition of fertilization?
Egg leaves the efferent pore in ovary. Enters coelom then goes into a single ostium via cilla uptake. Enters oviduct then into the noidamental or shell gland puts a coating or shell on the egg. Then it goes into the isthmus to the uterus to the vagine finally to cloaca.
Where does fertilization occur?
shell gland/noidamental or ovary duct
how long can FEMALE sharks store sperm?
up to a year
Do male sharks store sperm?
some have a sperm sac of store
How many testie do sharks have?
2
How does the white tip reef shark copulate?
bites on, rap body around and inserts clasper
How do big pelagic sharks copulate?
May swim belly to belly
Which clasper is used in copulation?
either side- which one dictates what tube is used in female
How do skates copulate?
May lie side to side, slow sperm transfer may last over an hour
What special adaptation do skates have?
Malar-cheek and alar-wings spines
may help males hold on
only males
matures males have both, develop young in life
Do nurse sharks block mating?
yes, display avoidance behavior by arching back and rolling
when ready they cup pelvic fins to direct claspers
Where does the epigonal organ lie?
around the testies and organ
What function does the epigonal organ play?
produces secretions for reproduction, leucocytes and immune
What does the testie produce?
spermatozoa and hormones
What path do sperm take?
they go to efferent ductules, then epididymis, vas deferns(ductules deferens) then seminal vesicles. there are secretions along the way
Where does the urogenital papilla dump?
cloaca
What is the function of the leydig gland?
Anterior end is involved in reproduction
posterios end is part of the kidney that produces urine
WHat drains kidney?
accessory urine ducts
Where does the clasper insert and how does it hold on?
base of the uterus
spurs erect after insertion
What do claspers look like in mature males?
Hard, longer than pelvic fins
How do southern stingrays mate?
vent to vent
multiple males with one female
How do Atlantic stingrays mate?
males have pointy nose, teeth change to sharp during seven month mating period.
sperm is stored
What are siphon sacs used for?
Maybe to force sperm out. Siphon sacs are filled with sea water then the water is forced out pushing sperm out in front.
Only has water during mating
What are pheromones?
hormones that attract males
Do skates and rays have a siphon sac? If not what do they have?
no, they have an alkaline gland and clasper gland
What does the alkaline gland produce?
proteins that cause contractions of the uterus to draw seamen in
What is the function of the clasper gland?
pumps secretions, chemicals, water and sperm, into clasper. may help nourish sperm
entire contents goes into female
Can sharks have multiple paternity?
yes, been seen in nurse and lemon
What is virgin birth?
In bonnethead, bamboo and black head: it is thought that the polar body may fertilize egg
Pups have been known to last for 5 yrs
What is viviparity vs oviparity
Viviparity-live offspring born from female
oviparity- eggs layed by female
What is oviparity?
external development of offspring
offspring hatch from egg cases
Who does oviparity?
skates and some sharks Ex. heterodontidae - horn, scyliorhinidae - catshark, hemisyllidae - carpetshark
What is the ancestrial condition?
oviparity
WHere does the egg case develop?
Outside the body
use yolk reserve for food
What strategies start with egg?
All
How is a hammerhead born?
with the cephalofoil folded over
How do nutrients cycle in egg cases?
throuhg tiny pores in egg case
shark beats its tail and circulates the water
What is aplacental viviparity?
have yolk, may uses a placental analog or trophonemata
What is viviparity?
live young are born once gestation is reached
ex. rays, guitarfish, sawfish, nurse, dogfish, sand tiger, lemon, hammerhead
Who uses trophonemata and what are they?
Myliobatiformes- finger like extensions of the uterine
What is the life cycle of a nurse shark?
Gestation: 5-6 mo Maturity: 10-20 yrs Reproductive cycle: 2yrs # of young 20-50 aplacental viviparity-nourishment is yolk egg case
What is the life cycle of a dogfish shark?
Gestation: 2 yr Maturity: 12-14 yrs Reproductive cycle: 2yrs # of young 2-15 young aplacental viviparity form a candle
What is the life cycle of a sand tiger shark?
Gestation: 12 mo Maturity: 6-12 yrs Reproductive cycle: 2yrs # of young 1-2 aplacental viviparity - ovarian cannabalism
What is ovarian cannabalism?
the first pup down eats the other unfertilized eggs has the come down
have specialized teeth, born with huge stomach and about 1 meter in legth
How does the trophonemata work?
embryos sit on top of finger like protrusions and absorb histotroph (uterine milk)
What is placental viviparity?
have yolk sac placenta
10% are
ex. hammerhead and lemon
What are appendiculae?
some placenta have fuzzy things on cord to absorb nutrients
What is the life cycle of a bonnethead?
Gestation: 4 1/2 mo
Maturity: 2-3 yrs
# of young 2-12
placental viviparity
mate in fall store sperm till spring in oviducal gland
Fertilize and have thin membrane added in oviducal gland
give birth in nursey areas
Where does fertilization occur?
oviducal gland
What is the general trend from oviparity to viviparity?
shift from oviparity to viviparity, few better developed young, many ways to nourish young
What are the problems with viviparity?
long period before maturity long reproductive cycle small broods low reproductive rate low fecundity easily over fished all leads to overexploitation and non-sustainable shark and ray populations
All skates are ______?
egg laying
What are odor plumes?
Complex, dynamic, three-dimensional structures used by many animals to locate food, mates, home sites, etc.
Composed of dispersing odor patches and vorticity eddies
Rheotaxis vs. Eddy Chemotaxis
Rheotaxis Orientation to the large-scale flow field Eddy chemotaxis Tracking the trail of small-scale, odor-flavored turbulence (tracking the wake of their moving prey) Olfaction and lateral line canals Pinpointing the source of the plume Olfaction and lateral line canals Energy dissipates faster
What were the four targets?
Odor alone: odor nozzle
Odor/turbulence: brick on odor side
Seawater alone: nozzle without odor
Seawater/turbulence: brick on unflavored side
Was there a significant difference Intact vs. Lesioned?
Lateral Line Intact
Light conditions – success rate = 100%; search time = 70 ± 10s
Dark conditions – success rate = 100%; search time = 63 ± 14s
Lateral Line Lesioned
Light conditions – success rate = 71%; search time = 291 ± 78 s
Dark conditions – success rate = 31%; search time = 508 ± 59 s
What does this say about the typical food tracking behavior in M. canis?
While olfaction and turbulence play a primary role in the tracking of prey by M. canis, vision does not.
What odor target had the most strikes for intact?
In light odor and turbulence 18 stirkes
What odor target had the most strikes for intact?
in the dark odor alone 5
Did the presence or absence of light have any significant effect on this preference?
no
Based on these results, is there a difference in the target preference of M. canis with the lateral line intact vs. lesioned? In the light vs. dark?
Yes. While the odor treatment is still preferred over seawater in light conditions, there is less distinction in preference between odor alone and odor/turbulence. In the dark, there appears to be no significant preference for any one target.
What occurred when a shark was attracted to a source area by an odor, but then nearby an electrode was switched on bypassing the nearby odor?
The electrode mimicked a breathing flounder and the shark would strike the electrode, ignoring the odor that initially brought it to the area.
Electroreception is chosen over odor
What happened when sharks had a disabled lateral line?
No longer discriminated between the source of odor/turbulence and odor alone.
Increased search time
Lost precision
What were intact animals more attracted turbulence paired with odor or the odor alone?
Animals were more attracted to turbulence on the odor side than odor by itself.
Odor stimulation
Intact animals orient to mean flow of the flume
Visual information not critical
Olfaction triggers upstream swimming with info provided by lateral line
What did the sharks exhibit when in light and in tact?
What happened in dark?
-Swam up stream and directly to odor plum
Majority of first strikes occurred on the source
Strikes then occurred on both targets on odor side and rarely on a target on seawater side
Pattern showed interest in target rather than first encounter
-No different than from in light
Showed vision is not needed
What happened when lesioned in light?
What happened in dark?
-Displayed same search behavior but swam closer to bottom
-Few could locate source
Ran accidently into source
Frantic and erratic behavior
Most were unsuccessful
Motivated to find plum but was unable to find
