Chordata (Fish)
Nealansh Gupta, Siddhartho Bhattacharya, Richard Tong
Period 1
http://www.hilariousheadlines.com/talk/wp-content/uploads/2009/06/reef-fish.jpg
Siddhartho Bhattacharya
Phyla
Myxini: jawless Hagfish, snake like
Cephalaspidomorphi: Lampreys; oldest living lineage of verabrates. 35
species
Chondrichthyes: Sharks, rays, etc. The biggest and most successful
predators
Actinopterygii: Ray-finned fishes; common fishes: bass, clownfish, tuna, etc.
Actinistia: Lobed fin, spike containing fish
Dipnoi: Lungfish, freshwater
Nealansh Gupta
Examples
Myxini (hagfish)
http://en.wikipedia.org/wiki/File:Pacific_hagfish_Myxine.jpg
Cephalaspidomorphi) (Lamprey)
http://en.wikipedia.org/wiki/File:Diversas_lampreas.1__Aquarium_Finisterrae.JPG
Chondrichthyes (Shark)
http://en.wikipedia.org/wiki/File:White_shark.jpg
Actinopterygii (regular fish)
http://z.about.com/d/animals/1/G/s/Q/fishes.jpg
Actinistia (coelacanths)
http://en.wikipedia.org/wiki/File:Latimeria_Chalumnae__Coelacanth_-_NHMW.jpg
Dipnoi (South American Lungfish)
http://en.wikipedia.org/wiki/File:Lepidosiren_paradoxa_0.jpg
Richard Tong
Body Cavity
All contain a coelom (fluid filled space
separating digestive tract from the outer body
wall; tissue usually derived from the
mesoderm.
Nealansh Gupta
Body Symmetry
All fish are bilateral (mirror image halves)
Myxini and Cephalaspidomorphi also contain
radial symmetry (symmetry radiating along the
center)
Siddhartho Bhattacharya
Nervous System
All are cephalized with brains
Myxini: contain 2 brains. Lack a SNS. Contain free nerves throughout
skin.
Cephalaspidomorphi: Complete CNS.
Chondrichthyes: Simple brain, simple column, simple network of
nerves.
Actinopterygii: complete CNS
Actinistia: CNS
Dipnoi: CNS
Circulatory System
Richard Tong
ALL HAVE CLOSED CIRCULATORY SYSTEMS
Myxini: primitive circulatory sytem with 4 hearts, one is brachial and serves as main
pump while the other 3 serve as accessory pumps.
Cephalaspidomorphi: two chambered heart.
Chondrichthyans: two chambered heart. RBC created not in bone marrow but in the
spleen and special tissue around gonads.
Actinoterygii: two chambered heart. No separation of oxygenated and deoxygenated
blood.
Actinistia: two chambered heart.
Dipnoi: partial four chambered heart. Separation of oxygenated and deoxygenated
blood
Nealansh Gupta
Digestive System
All ingest through the mouth
Myxini: Eat dead things from the inside out. Food in gut is enclosed in an
impermeable membrane.
Cephalaspidomorphi: Use teeth to get through skin to suck blood. Gut is
their stomach.
Chondrichthyes: Short digestive tract with a spinal valve within shark
intestine to increase SA and prolong food passaging.
Actinopterygii, Actinistia, Dipnoi: Breakdown in esophagus. food digested in
stomach and processed in finger shape pouches, secrete enzymes and
absorb nutrients. Intestine completes process.
Richard Tong
Excretory System
All fish excrete through anus. All have kidneys
Myxini, Cephalaspidomorphi: Have 2 kidneys. Only use their
mesonephric kidney (do not use the other one)
Chondrichthyes: Sharks urinate through penis.
Actinopterygii, Actinistia, Dipnoi: Contain a urinary bladder.
Siddhartho Bhattacharya
Locomotion/Musculature
Musculature: All contain a complex muscle system similar to that of humans
Myxini: swim in snakelike fashion by using their segmented muscles to exert force on their
notochord
Cephalaspidomorphi: they use an anguilliform (movement by snaking body through water)
similar to myxini, but laterally direct a wave along body. Have the ability to swim backwards.
Chondrichthyans: contain fins for movement; shark like chondrichthyans contain a
heterocercal tail for locomotion and rays contain flexible pectoral fins
Actinoterygii and Actinistia: anterior to posterior sequential contractions along one side of the
body with simultaneous relaxation along other side. Actinistia also use fins.
Dipnoi: contain small leg-like appendages to move over rocks and mud and all other surface
obstacles.
Nealansh Gupta
Skeletal Type
Myxini have no vertebrae but notochord (strong flexible rod of
cartilage); all other phyla contain a vertebrae
Myxini, Cephalaspidomorphi, and Chondrichthyans contain
cartilage skeletons (Chondrichthyans have calcium cartilage)
Actinoterygii, Actinistia, and Dipnoi have bone skeletons.
Actinoterygii: fins supported by flexible bone rays
Actinistia and Dipnoi: fins supported by rod shaped bones and
spikes
Siddhartho Bhattacharya
Sensory
Structures/Features
All have lateral lines (detects motion/vibration in water)
Myxini: 2 simple eyespots. No eye muscle. Single nostril. 6-8 barbels
(whiskerlike tactile sensory organ near mouth)
Cephalaspidomorphi: 2 large eyes. one nostril on top of head
Chondrichthyes: Keen smell. 2 complex eyes (contract/dilate). 2 nostrils. May
have sharp hearing. Electroreception.
Actinopterygii, Actinistia, Dipnoi: 2 complex eyes. Inner ears. Smell. two nostrils.
Reproduction
Nealansh Gupta
All are sexual reproduction. All external fertilizers (oviparous) except sharks. All
have testes and ovaries.
Myxini: Some are hermaphroditic (but only one gamete functions) no larva stage
Cephalaspidomorphi: Larva stage
Chondrichthyes: Internal fertilization. Fetus can grow inside female, can be in
egg outside body, maintain a placental link.
Richard Tong
Gas Exchange
All have gills, allow for oxygen carbon dioxide exchange through capillary
network.
Water pumped over gills pushing oxygen poor water out and
pulling in oxygen rich water through mouths.
Myxini, Cephalaspidomorphi, Chondrichthyes: contain multiple gill openings
Dipnoi: Have paired lungs; must surface to gulp air. Some are obligate air
breathers (must breathe air periodically)
Siddhartho Bhattacharya
Other
Myxini: Produce slime to escape capture and distract predators.
Cephalaspidomorphi: Attack prey by attaching mouths to animal and use
teeth to cut through skin and scales to suck blood.
Chondrichthyes: sharks jaw is not attached to its cranium. It has a layer of
tiny hexagonal plates which give some strength.
Actinopterygii: comprises of nearly 95% of the 25,000 species of fish
Actinistia: Have a symmetrical tail
Dipnoi: Contain little legs for movement
Richard Tong
QUIZ QUESTIONS!
WHAT PHYLUM DOES NOT
HAVE A VERTEBRAE?A.
ChondrichthyesB. MyxiniC.
ActinistiaD. Dipnoi
MYXINI
Which Phylum is a
coelomate?
A. Porifera
B. Cnidaria
C. Chordata (fish)
D. Platyhelminthes
Chordata (fish)
WHICH CONTAIN A
CEPHALIZED NERVOUS
SYSTEM?
A. Chondrichthyes
B. Myxini
C. Actinistia
D. All
All
True or False:
All Chordata (fish) contain
lateral lines
TRUE
THE END
http://www.tudiscovery.com/tiburones/que_es/popup_que/asset/07914907646434433_elephant_shark_380x290.jpg
http://blog.rocketboom.com/post/102948092/the-top-15-most-bizarre-sea-animals