Body Shape Flashcards
What is external anatomy categorized according to? (6)
- body shape
- scale types (if present)
- shape and placement of fins
- mouth shape + position
- gill openings
- sense organs
What are the 3 medial fins
- dorsal
- anal
- caudal
What are the 2 paired fins?
- pectoral
- pelvic
What is an operculum?
- single gill opening
What does mouth orientation depend on? give an example
- how fish feeds
- ex. bottom feeder = on bottom of body
how are gill openings derived?
- phylogenetically
What are 2 examples of sensory organs in fish?
- lateral line
- barbells
What are the 9 different types of fish?
- rover predator
- lie in wait predator
- surface oriented fish
- bottom rover
- bottom clinger/hider
- flatfish
- rat tail
- deep-bodied
- eel-like
What are the main characteristics of rover-predators? (4)
- fusiform
- narrow caudal peduncle/forked tail
- even distribution of fins
- constant movement
What does the fusiform shape allow for in rover-predator fish? Why do they have this adaptation
- hydrodynamic
- need swimming to be as efficient as possible
What is a peduncle? What is it’s function?
- narrow part before tail/tail
- generates thrust while minimizing drag
What does an even distribution of fins do?
- allows them to orient their body better
How did rover-predators get their body form?
independent (convergent evolution - they have no common ancestor
Give 5 examples of rover-predator fish
- swordfish
- tuna
- shark
- trout
- minnows
What are the main characteristics of lie-in-wait predators? (6)
- piscivorous
- fusiform (torpedo shape)
- flattened heads
- long pointed snouts
- large teeth-filled mouths
- dorsal + anal fins far back
- cryptic colouration
Define piscivorous
- ambush other fish
What is the advantage of lie-in-wait fish having lots of teeth?
- catch fish in mouth
What is the advantage of lie-in-wait fish having their fins oriented where they are?
- generates thrust
- can rapidly accelerate
What is the advantage of the colouration of lie-in-wait fish?
- can hid and blend in
Give 4 examples of lie-in-wait fish
- pike
- gar
- barracuda
- needlefish
What are the main characteristics of surface oriented fish? (5)
- small
- dorsoventrally flattened head
- large eyes
- fusiform to deep body
- posteriorly located dorsal fin
What is the orientation of surface oriented fish mouths?
- upward pointing
What is the function of surface oriented fish?
- capture phytoplankton & small fish at surface
- obtain O2 from water-air interface
Define aquatic surface respiration
- obtain O2 from water-air interface
What is a major disadvantage of being a surface oriented fish? how do they minimize it?
- breaking surface tension of water gives them away to birds and other terrestrial animals
- flattened head and fin orientation (do not pop out of water)
Define hypoxic
- low oxygen
How do fish obtain oxygen where it is lower?
- in deeper water they “sip” because their lower lip protrudes
What are the 2 general features of bottom fish?
- swim bladder often reduced/absent
- flattened
What are the 5 subtypes of bottom fish?
- bottom rovers
- bottom clingers
- bottom hiders
- flatfish
- rattails
What are the main features of bottom rovers? (4)
- humped back
- flat head/rover-predator body
- enlarged pectoral fins
- barbels
Why do bottom fish often lack a swim bladder?
- want to be negatively buoyant (do not want to float)
give an example of a bottom rover
- north american catfish
What are the main features of bottom clingers? (4)
- small flattened heads
- large pectoral fins and modified pelvic fins
- grippers/suction cups
Why do bottom clingers have modified pelvic fins?
- to grip bottom in fast flowing streams/intertidal zones
give 3 examples of bottom clingers
- sculpins, gobies, clingfish
What are the major features of bottom hiders? (4)
- similar to clingers but longer with smaller heads
- lack clinging devices
- can hide in crevices/under rocks
- frequently sedentary
Give 2 examples of bottom hiders
- darters
- blennies
What are the 2 subcategories of flatfish?
- flounders
- skates and rays
What are the main features of flounders? (5)
- deep bodied/laterally compressed
- lie on side
- mouth oriented for bottom feeding
- eyes dorsally positioned
- larvae bilaterally symmetrical
Define compressiform
- laterally compressed (sideways)
- migration of one eye to top as one side always facing down
What are the major features of skates and rays?
- dorsoventrally flattened
- large pectoral fins used as wings
- ventral mouth
- dorsal spiracles
define depressiform
- dorsoventrally flattened
What is the function of spiracles?
- breathing in, and out through gill slits
What are the major features of rattails?
- deep sea habitat
- large pointy snouted heads
- large pectoral fins
-tapered “rattail”
How did rattails evolve?
- independently of osteichthyes and chondrichthyes
What did flatfish derive from osteichthyes?
- bony tails
What did flatfish derive from chondrichthyes?
- large pectoral fins for swimming
What are the major features of deep-bodied fish? (5)
- laterally flattened
- high pectoral fins with pelvic below
- fins have sharp spines
- small mouth protrusible
- large eyes
What is the difference between the shape of flatfish and deep-bodied fish?
- deep are deep compared to length and do not lie on one side
What are the functions of deep-bodied fish fin placement?
- maneuver tight spaces
- bottom foragers
what features allow for a deep-bodied fish to forage for food?
- large eyes help them see
- fins help maneuver
What is the function of spines on fins?
- increases effective spine and is harder to eat it
Give 2 examples of deep-bodied fish
- sunfish
- blue gill
What are the major features of eel-like fish?
- elongate
- blunt/wedge shaped heads
- tapering/rounded tails
- large dorsal and anal fins
what happens to the caudal fin in eel-like fish?
- fuses with dorsal and anal
What does the loss of paired fins in eel-like fish allow for?
- easier to fit in small spaces and dig
What is the functional significance of eel-like fish features
- hiding/foraging in crevices/holes
- burrowing
Give 3 examples of eel-like fish. Why are they similar?
- eels
- lamprey
- lungfish
- CONVERGENT EVOLUTION
