aquatic vertebrates part iii vertebrate zoology (vz lecture08 – spring 2012 althoff - reference...
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Aquatic VertebratesPART III
VERTEBRATE ZOOLOGY (VZ Lecture08 – Spring 2012 Althoff - reference PJH Chapter 6)
paddlefish
longnosegar
Arapaima
bullhead catfish
Sturgeon & Paddlefishes
Acipenseriformes: Sturgeons & Paddlefishes
• What is unique? actually lack ENDOCHONDRAL BONE
• Two extant families—so limited diversity today
• Sturgeons: 24 species, only in N. Hemisphere. Commercially important as rich flesh AND considered the best caviar…result: overexploitation. 1-6 m in length
• Paddlefishes: 2 species, one in Mississippi River valley & one in Yangtze River of China. Less dermal ossification than sturgeons. > 2m in length. American paddlefish heavily fished for caviar.
Rostum richlyinnervated with ampullary organthat apparentlyhelps to detect minute electric Fields
Planktivores in American. Carnivores inChina—almostextinct
Paddlefishes
Ostariophysi: Predominant fishes of the world’s freshwater
• Ostariophysans (characins, minnows, & catfishes)
• What is unique? Two distinct ________ characters ,
reflected in their name “bone” “bladder” (Greek)
Small bones that connect swim bladder to inner ear. Swim bladder acts as amplifier and the chain of bones as condutors greatly
enhances hearing sensitivity of these fishes. This arrangement is known as the _______________________
Result: among fishes, the most sensitive to sounds and broadest frequency range of detection
Weberian Apparatus
(present inostariophysans)
Fig. 6-11 p135 PJH
Scaphum
Claustrum Intercalarium
Tripus
Gasbladder
Ostariophysi: Predominant fishes of the world’s freshwater
• Two distinct derived characters……
Presence of fright or alarm substance in the skin: _________________________ released intowater when skin is damaged produces a fright reaction in nearby members of their own species (i.e., conspecifics) and otherostariophysan fishes
Result: fish picking up chemical signal may rush for cover or form a tighter school
Ostariophysans
• Characins (piranhas, neon tetras, and many other familiar aquarium fishes)
• Tropical fishes of American and Africa
• Carps and minnows in freshwater
• Catfishes
• Electric knifefishes
Locomotion in Water
• Swimming results from ______________________ sequential ____________ of the muscle segments along one side of the body and the _____________ _______________ of those of the opposite side.
• Most of the power for swimming comes from muscles in the posterior region of the fish
• Three types of undulatory motions of fishes:1) _______iform – highly flexible fishes2) _______iform – undulations limited mostly
to caudal region3) _______iform – body inflexible, undulation
is limited to caudal fin
Fig. 6-13 p137 PJH
Anguilliform(eel)
Carangiform(trout)
Ostraciiform(boxfish)
Undulatory Motions
• hagfishes• lampreys• most sharks• sturgeons• arawans• many catfishes• many elongate,
spiny rayed fishes
Anguilliform Carangiform
• trout• salmon• sunfishes• bass• perches• Etc.
Ostraciiform
• boxfish• trunkfishes• cowfishes
Specializations that have _______________efficiency of the different modes of swimming
• __________________
• __________________
• __________________
• __________________
Know Some
specific examples
GRAVITY
LIFT & BUOYANCY
THRUST
Fig
. 6-
15 p
139
PJH
UNDULATION OSCILLATION
Tru
nk
Cau
dal
Do
rsal
An
al
Pec
tora
l
REDUCING DRAG: Shape matters
Notice: _____________ ”design”
Drag ratios: _________________ profile of thickness
Rel
ativ
e dr
ag
Profile thickness d/l
Dire
ctio
n of
flo
w
Dire
ctio
n m
ovem
ent
Streamlined (teardrop shaped) when minimalinertial drag
a) maximum width ~ ____ of body lengthb) maximum width ~ ____ of length from
leading edge
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