marine fishes
DESCRIPTION
Marine Fishes. Read Chapter 9 Pages 154- 178. Chordates. All chordates have (at least during some period of their life) Dorsal nerve cord Gill slits Notochord Post-anal tail These are the 4 basic characteristics of all chordates. Bridging the gap Chordates w/o backbone. Tunicates - PowerPoint PPT PresentationTRANSCRIPT
Marine FishesMarine FishesRead Chapter 9 Pages 154- 178Read Chapter 9 Pages 154- 178
ChordatesChordates
All chordates have (at least during some All chordates have (at least during some period of their life)period of their life)– Dorsal nerve cordDorsal nerve cord– Gill slitsGill slits– NotochordNotochord– Post-anal tailPost-anal tail
These are the 4 basic characteristics of all These are the 4 basic characteristics of all chordates.chordates.
Bridging the gapBridging the gapChordates w/o backboneChordates w/o backbone
TunicatesTunicates– Not fish but chordatesNot fish but chordates
Lancelets: Not a Vertebrate, but a ChordateLancelets: Not a Vertebrate, but a Chordate– Chordate characteristics throughout life-Chordate characteristics throughout life-– But no backboneBut no backbone– Subphylum CephalochordataSubphylum Cephalochordata
The FishesThe Fishes
Note: The term Note: The term fish fish refers to a single fish or a refers to a single fish or a group of the same species of fish.group of the same species of fish.
FishesFishes refer to more than one species of fish. refer to more than one species of fish.
FishFish
Structurally simplest living vertebratesStructurally simplest living vertebrates Probably ~30,000 speciesProbably ~30,000 species At least half of all known vertebrate species At least half of all known vertebrate species
are fishesare fishes At least half of all known fishes are marine At least half of all known fishes are marine First appeared about 500 million years ago First appeared about 500 million years ago
and were the first vertebratesand were the first vertebrates– every other vertebrate has ultimately descended every other vertebrate has ultimately descended
from a fish-like ancestorfrom a fish-like ancestor
Three major groups of FishThree major groups of Fish
Jawless fishes (Agnatha)Jawless fishes (Agnatha) Cartilaginous fishes (Chondrichthyes)Cartilaginous fishes (Chondrichthyes)
– Sharks and rays (elasmobranchs)Sharks and rays (elasmobranchs)– Ratfishes (chimeras) (Holocephalins)Ratfishes (chimeras) (Holocephalins)
Bony fishes (Osteichthyes)Bony fishes (Osteichthyes)– Lobe-finned fishesLobe-finned fishes– Ray-finned fishesRay-finned fishes
Jawless FishesJawless Fishes
Most primitive living fishesMost primitive living fishes Feed by suction with a round, muscular Feed by suction with a round, muscular
mouth and rows of teethmouth and rows of teeth Long, cylindrical bodyLong, cylindrical body No paired fins or scalesNo paired fins or scales Lampreys are parasites on other fishes and Lampreys are parasites on other fishes and
suck on their blood; hagfish typically feed on suck on their blood; hagfish typically feed on dead animalsdead animals
Jawless FishJawless Fish
Cartilaginous FishesCartilaginous Fishes
Sharks, rays, skates, chimeras (ratfishes)Sharks, rays, skates, chimeras (ratfishes)– Skeleton is made of cartilage, which is lighter Skeleton is made of cartilage, which is lighter
and more flexible than boneand more flexible than bone– Moveable jaws with well-developed teethMoveable jaws with well-developed teeth– Paired lateral fins for efficient swimmingPaired lateral fins for efficient swimming– Rough skin due to placoidscalesRough skin due to placoidscales
SharksSharks In some form, sharks have In some form, sharks have
been around for about 400 been around for about 400 million years. million years.
Even before dinosaurs Even before dinosaurs roamed the earth, sharks roamed the earth, sharks hunted through the hunted through the oceans! They're such oceans! They're such good survivors that they've good survivors that they've had little need to evolve in had little need to evolve in the last 150 million years. the last 150 million years.
Scientific Information: Scientific Information: Sharks belong to the class Sharks belong to the class of fish, Chondrichthyes.of fish, Chondrichthyes.
More on Sharks to come More on Sharks to come in a later lecture!!!in a later lecture!!!
Skates vs. RaysSkates vs. Rays
SkatesSkates– Oviparous (lay eggs)Oviparous (lay eggs)
Mermaids purseMermaids purse
– Do not have barbs, Do not have barbs, have thorns on their have thorns on their dorsal area or tailsdorsal area or tails Placement and number Placement and number
varyvary
– Small teethSmall teeth
RaysRays– Viviparous (bare Live Viviparous (bare Live
young)young)– Have BarbsHave Barbs
Above tailAbove tail
– In general, largerIn general, larger Tail almost 2x’s as long Tail almost 2x’s as long
as bodyas body
– Plate Like TeethPlate Like Teeth
Skates and RaysSkates and Rays
Flattened bodyFlattened body Large pectoral finsLarge pectoral fins
Rat Fishes (Chimeras)Rat Fishes (Chimeras)
Bizarre-looking, primarily deep-sea, Bizarre-looking, primarily deep-sea, cartilaginous fishescartilaginous fishes
Have only one pair of gill slits instead of 5-7Have only one pair of gill slits instead of 5-7 Have a long rat-like tailHave a long rat-like tail Feed on crustaceans and molluscsFeed on crustaceans and molluscs
Cartilaginous vs. Bony FishCartilaginous vs. Bony FishCartilaginousCartilaginous skeleton made of cartilage skeleton made of cartilage possess movable jaws mostly with possess movable jaws mostly with
powerful teeth. powerful teeth. mouth is located ventrally (under mouth is located ventrally (under
the head). the head). presence of paired lateral fins presence of paired lateral fins
allows for efficient swimming. allows for efficient swimming. skin is covered with small scales skin is covered with small scales
that have the same composition as that have the same composition as teeth.teeth.
BonyBony Skeleton made (at least partially) of Skeleton made (at least partially) of
bone bone Thin, flexible, overlapping scales Thin, flexible, overlapping scales
along the body along the body A flap of bony plates and tissue A flap of bony plates and tissue
known as the gill cover, or known as the gill cover, or operculum, that protects the gills operculum, that protects the gills
Protruding jaws with more freedom Protruding jaws with more freedom of movement than cartilaginous fish of movement than cartilaginous fish
The presence of a swim bladder The presence of a swim bladder – helps buoyancy and compensates helps buoyancy and compensates
for the relatively heavier bony for the relatively heavier bony skeleton skeleton
Highly maneuverable fins Highly maneuverable fins
Cartilaginous Vs. Bony – ExternalCartilaginous Vs. Bony – External
Cartilaginous vs. BonyCartilaginous vs. Bony
Cartilaginous vs. BonyCartilaginous vs. Bony
Cartilaginous vs. BonyCartilaginous vs. Bony
Cartilaginous vs. BonyCartilaginous vs. Bony
Extinct No MoreExtinct No More
Subclass Sarcopterygii-Once known only for Subclass Sarcopterygii-Once known only for fossils and thought to be extinct for 60 fossils and thought to be extinct for 60 million years-Named Latimeriachalumnaemillion years-Named Latimeriachalumnae
Preserved specimen of the Coelacanth is Preserved specimen of the Coelacanth is located in the HMNHlocated in the HMNH
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Fish Form and FunctionFish Form and Function