fishes Flashcards
What are some distinguishing characteristics of vertebrates?
vertebral column, brain encased in skull, closed circulatory system, various internal organs
What class do lampreys belong to?
petromyzontida
What are some unique characteristics that differentiate lampreys from other fish?
lack scales, jaws, and paired fins
How are adult lampreys different from their larval form?
adult lampreys are parasitic (using a buccal funnel covered in papillae) while larval lamprey are filter feeders
Do lamprey possess lateral lines? If so, what is its function?
yes, it is used to detect vibrations and currents
What is the function of the oral glands in lamprey?
they secrete an anticoagulating agent that prevents host’s blood from clotting and promoting blood flow
How many chambers does the lamprey (and all fish) heart have?
two chambers (one atrium and one ventricle)
What are the defining characteristics of the class chondrichthyes?
cartilaginous skeleton, paired fins, and jaws
What class do sharks, skates, and rays belong to?
chondrichthyes
Do sharks have lateral lines? If so, what is their function?
yes, like the lampreys it serves to detect movements, vibrations and currents
Where are the spiracles located on a shark, and what is their function?
they are located right behind the eyes and they provide a second entrance for the water so more oxygen can pass over their gills
What is unique about the liver of sharks?
it is filled with oil (squalene) that allows them to maintain buoyancy
What is the function of the rectal gland in sharks?
excrete excess salt for osmoregulation
Where are the rugae found in sharks, and what is their function?
they are found in the interior of the stomach, allowing it to expand
What is the function of the spiral valve in sharks?
to slow the passage of food and increase the surface area of the intestine to aid in digestion
What are the type of scales that are found on cartilaginous fishes called?
placoid scales (dermal denticles)
What are the characteristics of placoid scales?
stacked and have spiny toothlike projections. when stroking a shark from the head to the caudal fin, it feels smooth, but when stroked in the opposite direction it feels like sandpaper due to the spiny toothlike projections. the flattening in the forward direction helps reduce drag and make swimming more efficient.
How can you determine if a shark is male?
a male shark will have two claspers for depositing sperm into the female’s cloaca. internally male sharks will have two testes, although one is typically greatly reduced.
Do both male and female sharks possess a cloaca? What is its function?
yes both male and female sharks possess a cloaca. the cloaca is the opening where both the rectum and urogenital ducts empty.
How can a female shark be identified?
female sharks will lack claspers, and internally they will have paired ovaries that will contain eggs. in addition, the cloaca in females has urinary, digestive, and reproductive functions.
What class do the ray-finned fishes belong to?
actinopterygii
What are the defining characteristics of the class actinopterygii?
they possess a bony skeletal system unlike that of chondrichthyes, and their fins are supported by fin rays
What is the function of the operculum?
protects the gills and aids in respiration by pumping water over the gills
What is the swim bladder and what is its function?
the swim bladder is a gas filled sac used by ray-finned fishes for maintaining buoyancy.
What is the function of the gills in ray-finned fishes?
respiration and absorption of salt from surrounding water
How can you tell if a perch is female?
females will only have one ovary that produces eggs (but will have one that isnt functional as well)
How can you tell if a perch is male?
the male will have two testes that produce sperm
What are the characteristics of ctenoid scales?
ctenoid scales are comb-like teeth scales that are found in many ray-finned fishes, such as perch. the overlapping of these scales is what allows perch to be more flexible.
What is the function of the pectoral and pelvic fins?
maneuverability
What is the function of the dorsal and anal fins?
stability
What is the function of the caudal fin?
propulsion and power for swimming
What class do hagfish belong to?
myxini
What are some characteristics of the class myxini?
they lack the distinctive funnel shaped mouth found in lampreys, and instead have a mouth surrounded by 4 pairs of sensory tentacles. inside the mouth are tooth plates made of keratin to rasp away the flesh of dead organisms. they lack vertebrae and retain the notochord until adulthood (they are still part of subphylum vertebrata though). possess glands in the side of their bodies to secrete copious amounts of slime for defense.
