Chordates and Vertebrates. Chordates The notochord is an elongate, rod- like, skeletal structure...
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Transcript of Chordates and Vertebrates. Chordates The notochord is an elongate, rod- like, skeletal structure...
Chordates and VertebratesChordates and Vertebrates
ChordatesChordates The The notochordnotochord is an elongate, rod- is an elongate, rod-
like, skeletal structure dorsal to the gut like, skeletal structure dorsal to the gut tube and ventral to the nerve cord. tube and ventral to the nerve cord.
The notochord should not be confused The notochord should not be confused with the backbone or vertebral column with the backbone or vertebral column of most adult vertebrates.of most adult vertebrates.
The notochord appears early in the The notochord appears early in the embryo and plays an important role in embryo and plays an important role in promoting or organizing the embryonic promoting or organizing the embryonic development of nearby structures.development of nearby structures.
In most adult chordates the notochord In most adult chordates the notochord disappearsdisappears
In some non-vertebrate chordates and In some non-vertebrate chordates and fishes the notochord persists as a fishes the notochord persists as a laterally flexible but incompressible laterally flexible but incompressible skeletal rod that prevents telescopic skeletal rod that prevents telescopic collapse of the body during swimming.collapse of the body during swimming.
Primitive Jawless FishPrimitive Jawless Fish Lamphrey and Hag fishLamphrey and Hag fish The most primitive of the The most primitive of the
chordates evident in the fossil chordates evident in the fossil record are the jawless record are the jawless OstracodermsOstracoderms. .
They were jawless, bottom feeders They were jawless, bottom feeders
Their endoskeleton was cartilaginous Their endoskeleton was cartilaginous but the are covered with small bony but the are covered with small bony
platesplates They use a muscular pharynx to They use a muscular pharynx to
suck food into their mouths and to suck food into their mouths and to exchange gases in respiration. exchange gases in respiration.
Their gill slits were permanently Their gill slits were permanently open open
Jawless Fish cont.Jawless Fish cont. As the fish swam, this fin As the fish swam, this fin
configuration drove the animal configuration drove the animal down into the bottom where its down into the bottom where its food was located. food was located.
The bony plates were useful for The bony plates were useful for protection but inhibiting when rapid protection but inhibiting when rapid swimming was required. swimming was required.
They still had no axial skeleton They still had no axial skeleton These animals are long, slender eel These animals are long, slender eel
like organisms. like organisms.
These animals exist either as These animals exist either as bottom scavengers or parasites of bottom scavengers or parasites of other fish. (Hag fish top right)other fish. (Hag fish top right)
Jawed cartilaginous fishJawed cartilaginous fish The Chondrichthyes are the The Chondrichthyes are the
modern cartilaginous fish modern cartilaginous fish The present Chondrichthyes The present Chondrichthyes
include the sharks, skates and include the sharks, skates and rays. (Top left: skate Bottom rays. (Top left: skate Bottom leftleft
A ventral A ventral jawjaw with replaceable with replaceable teethteeth. The limited mobility of . The limited mobility of the jaw means that the shark the jaw means that the shark must thrash around to break must thrash around to break up its prey up its prey
Sharks must continually swim Sharks must continually swim to avoid sinking. (Thought this to avoid sinking. (Thought this was interesting!)was interesting!)
The gills are not protected by The gills are not protected by an operculum an operculum
Cartilagenous FishCartilagenous Fish
Cartilage is a soft, Cartilage is a soft, flexible materialflexible material End of your nose, earsEnd of your nose, ears
Cartilagenous fish Cartilagenous fish have an entire have an entire skeleton made of itskeleton made of it
Class ChondrichthyesClass Chondrichthyes Sharks, skates and Sharks, skates and
raysrays First jawed fishFirst jawed fish
Cartilagenous FishCartilagenous Fish Placoid Scales: tiny Placoid Scales: tiny
“teeth” that point towards “teeth” that point towards posterior of animalposterior of animal
Gill Slits: openings to the Gill Slits: openings to the gills gills Skates, rays and some Skates, rays and some
bottom-dwelling sharks bottom-dwelling sharks have gill slits on ventral have gill slits on ventral sideside
Spiracles: openings that Spiracles: openings that allow water to enter gill allow water to enter gill chamberchamber Behind eyeBehind eye
Mouth can be used to Mouth can be used to help spiracles pump help spiracles pump water over gillswater over gills
Cartilagenous FishCartilagenous Fish
FinsFins More rigid than bony More rigid than bony
fishfish Pectoral fins in sharks Pectoral fins in sharks
provide liftprovide lift In skates and rays In skates and rays
pectoral fins are more pectoral fins are more developeddeveloped
Skates and RaysSkates and Rays
Many species are Many species are bottom-dwellersbottom-dwellers
Stingrays have a Stingrays have a spine at the base of spine at the base of the tail that can inflict the tail that can inflict a stab wounda stab wound
Skates do not have Skates do not have spinesspines
Both eat crustaceans Both eat crustaceans and mollusksand mollusks
SharksSharks Group is more than 300 million years oldGroup is more than 300 million years old Lateral line organLateral line organ
Used to detect motion in the waterUsed to detect motion in the water Ampullae of LorenziniAmpullae of Lorenzini
Sense electric fields generated by fishSense electric fields generated by fish TeethTeeth
Constantly replacedConstantly replaced Many sharks have to swim as they can not pump water over their gills Many sharks have to swim as they can not pump water over their gills
SharksSharks
ReproductionReproduction ClaspersClaspers
Males use claspers to Males use claspers to transfer sperm to transfer sperm to femalesfemales
Located between the Located between the pelvic fin and bodypelvic fin and body
EggsEggs All sharks have eggsAll sharks have eggs Some species have Some species have
eggs that hatch eggs that hatch internally and are then internally and are then born liveborn live
Some species lay an Some species lay an egg case known as a egg case known as a Mermaid’s PurseMermaid’s Purse
Bony FishBony Fish
Bony fishBony fish Skeleton made of Skeleton made of
bonebone Have vertebraeHave vertebrae Have scales covered Have scales covered
with mucuswith mucus Barrier against infection Barrier against infection
and reduces friction and reduces friction with the waterwith the water
Found in every aquatic Found in every aquatic environmentenvironment
Bony FishBony Fish
Obtaining oxygenObtaining oxygen
Use gillsUse gills Located under a Located under a
protective flap called protective flap called the operculumthe operculum
Mouth and operculum Mouth and operculum open at the same time open at the same time as water is drawn in by as water is drawn in by the mouth and passed the mouth and passed over the gillsover the gills
Bony FishBony Fish LocomotionLocomotion
NektonNekton As opposed to planktonAs opposed to plankton
FinsFins Some are paired, others Some are paired, others
are singleare single Paired: pectoral and pelvicPaired: pectoral and pelvic
movementmovement Single: dorsal, anal and Single: dorsal, anal and
caudalcaudal Stabilization and thrust Stabilization and thrust
(power)(power)
PedunclePeduncle Used as a major marker Used as a major marker
for determining speciesfor determining species Base of caudal finBase of caudal fin
Bony FishBony Fish
Pelagic v. BenthicPelagic v. Benthic Pelagic refers to those Pelagic refers to those
living in the middle of the living in the middle of the water column, open oceanwater column, open ocean
Benthic refers to those Benthic refers to those living on the bottomliving on the bottom
SpeedSpeed Depends on shapeDepends on shape Faster fish have more Faster fish have more
sharp angles and bigger, sharp angles and bigger, forked caudal finsforked caudal fins
Bony FishBony Fish
TemperatureTemperature Bony fish are ectothermicBony fish are ectothermic Their body temperature Their body temperature
depends on the depends on the temperature of the temperature of the environmentenvironment
BuoyancyBuoyancy Swim bladderSwim bladder Neutral buoyancy is when Neutral buoyancy is when
the fish neither sinks or the fish neither sinks or floatsfloats
Swim bladder contracts Swim bladder contracts and fish sinks, bladder and fish sinks, bladder expands and fish risesexpands and fish rises
Bony FishBony Fish FeedingFeeding
Parasitic (lamprey)Parasitic (lamprey) PredatoryPredatory Strainers (plankton-Strainers (plankton-
eaterseaters Suckers (use change Suckers (use change
in volume to suck prey in volume to suck prey into mouth)into mouth)
DigestionDigestion One-way digestive One-way digestive
system coupled with a system coupled with a closed circulatory closed circulatory system and 2-system and 2-chambered heartchambered heart
Bony FishBony Fish
ReproductionReproduction Takes place during spawningTakes place during spawning Sperm and eggs are released into the water or fertilization takes Sperm and eggs are released into the water or fertilization takes
place internallyplace internally Eggs develop either floating or attached to a substrateEggs develop either floating or attached to a substrate