Fish Flashcards
What is a grade?
taxon united by a level of morphological or physiological complexity
Are fish a grade or a clade?
grade
Give 3 characteristics of agnathans
jawless, no paired fins, 2 chambered heart, 7+ gill pouches, notochord in larvae and adults
What is a strange characteristic of hagfish considering they are vertebrates?
they have no vertebrae (just a fibre-sheathed notochord)
What type of lifecyle do lampreys have?
anadromous
What is an anadromous lifecycle?
start in freshwater (streams, lakes, rivers, etc.), migrate to the ocean, then return home to spawn and die
What are some major evolutionary transitions between agnathans and gnathostomes?
jaws, duplication of HOX gene complex, well-developed lateral line, ribs, 2 nostrils..
What developed into protojaws during the evolution of jaw?
madibular gill arch
What are pleiotrophy genes?
More than 1 effect
What developmental toolkit gene is upregulated to reduce eye structure and increase tastbuds?
Hedgehog
What are the sensory hairs all over fish called?
Neuromasts- bending = feedback
What are the 2 types of neuromasts?
superficial and canal
What are statocysts used for?
orientation - in inner ear
What are the 2 different swimming types and their benefits?
1- body/caudal fin- good thrust and acc.
2- median/paired fin- good manouverabilty
What is an example of an anguilliform swimming type?
eel
What is an example of a carangiform swimming type?
trout
Why is there high propelllor efficiency?
As acting on large vol. of water
What are the 3 main forms of drag?
skin, shape pushing and vortices
What are 2 classifications of fish?
bony and cartilagionous
What are some major problems with aquatic existence?
density of water, need gases for resp., buoncy and temp. regulation…
What does ossification of dermal elements in Osteichthyes mean?
scales become bony
What is a major change is bony fish skeleton over time?
thinner and lighter
What is the difference between CYCLOID and CTENOID scales on teleosts?
cycloid- primitive- annual growth rings
ctenoid- fast swimmers- serrated edges = microturbulence = reduce drag
Why does teleost skin appear silvery?
As reflective guanine layers under skin
what are shark placoid scales?
‘dermal denticles’ - dont grow + same structure as a tooth (3-layers)
What are the gills enclosed in in teleoosts?
opercular cavities
How do sharks maintain bouyancy without swim bladder?
Vast liver, rich in squalene = neutral body density
What is fercundity?
ability to produce an abundance of offspring
What are perpetual swimmers?
lost function to pump current over gills os have to keep swimming with mouth open for respiration
How does a physoclists swim bladder work?
o2 carrying capacity of blood dependant on pH , therefore use lactate transfer from out to in vessels at gas gland on ventral bladder wall to liberate 02 into swim bladder
What is an example of regional heterothermy?
muscles warm up in TUNA
How marine do teleosts regulate osmolarity and ionic?
drink, little urine, excess NaCl out of gills
What is an example of an adaptation to low CO2?
air-breathing e.g. big lips and true lung also bubble nests (make Betta fish)
