Chordata: Fish

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Chordata Fish
Chordata (Greek) chorda, meaning string

• Agnatha, Chondrichthyes and Osteichthyes
• By J-Z and Lucy C.

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Agnatha

• Greek without jaw
• Bilateral coelomates
• Embryonic notochord
• Notochord supporting rod running the
• length of Chordata animals composed of large
  cells packed within a firm connective tissue
  sheath, the notochord lies between the neural
  tube (spinal cord) and the gut
• Ectothermic (cold-blooded, controls body
  temperature using the environment)
• Heart contains 2 chambers

http//alpha1.fmarion.edu/bio106lab/Resources/lam
prey.jpg
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Agnatha, continued

• The digestive system lacks a stomach
• A light-sensitive pineal eye is present
• Cartilaginous endoskeletons
• External fertilization both ovaries and testes
  present in individual, no larval stage
• Seven or more paired gill pouches
• supported by branchial arches close to the body
  surface
• Use gills to trap food as well as for breathing

www.zoology.ubc.ca/labs/biomaterials/slime.html
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Agnatha, continued

• The existing agnathans are
• Lampreys
• Feeds by clamping onto tissue of live fish and
  uses rasping tongue to penetrate skin
• Sucks blood and eats living tissue
• Larvae live in freshwater but migrate to
  sea/lakes when mature

Digestive System
Respiratory System
Circulatory System
http//www.bishops.k12.nf.ca/wells/VERTS/Agnatha.h
tm
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Agnatha, continued

• Hagfishes
• Scavengers, suspension-feeders
• Lack larval stage
• Lives entirely in salt water

www.uwlax.edu/.../faculty/tyser/QME/page1.html
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Chondrychthyes

• Gr. Cartilaginous endoskeleton, lacking true
  bone
• Skeleton is flexible but strengthened by
  calcified granules
• Includes sharks, rays, and chimaeras (ratfish)
• Also bilateral coelomates
• Has jaws
• Paired appendages
• No swim bladder or lung

http//www.greatwhiteadventures.com/guadalupe.html
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Chondrychthyes, continued

• Sensory organs include
• inner ear for hearing, paired nasal cavities for
  smelling, and eyes
• Poor eyesight made up for by well developed
  lateral line (electroreceptive) system
• Lateral line system a line of sensory organs
  running down the side of the body that can detect
  very small changes in water pressure

members.tripod.com/ranndino/animals.html
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Chondrychthyes, continued

• Digestive system with a j-shaped stomach
• Intestine short but surface area increased by a
  spiral valve (corkscrew shaped ridge in tract)
• Respiration by five to seven pairs of gills with
  separate and exposed gill slits
• no operculum (hard bony flap to protect gills)

www.garbled.net/.../lba_ratfish_Lg.jpg.25.html
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Chondrychthyes, continued

• Separate sexes internal fertilization and direct
  development
• Oviparous lay eggs that hatch outside mother's
  body
• Ovoviviparous retain fertilized eggs in
  oviduct, hatched within uterus and develop into
  young
• Viviparous young develop within
• uterus (no eggs) surrounded by
• placenta

http//www.flmnh.ufl.edu/fish/Gallery/Descript/Swe
llShark/SwellShark.html
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Chondrychthyes, continued
http//www.enchantedlearning.com/subjects/sharks/a
natomy
http//www.pelagic.org/biology/int_anatomy.html
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Osteichthyes

• Greek Bony fish
• Named for Endochondrial bone (replaces cartilage
  as fish mature)
• Most are Actinopterygii ray-finned fish
  (dominant over lobe-finned)
• Ray-finned fish thin, flexible skeletal rays,
  modified for maneuvering, defense, etc.
• Ex bass, trout, tuna, herring
• Lobe-finned fish the other type of bony fish,
  have muscular fins supported by bones, lungs aid
  gills in breathing air
• Ex represented by only one known species,
  Latimeria chalumnae (see page 640 for pic) rest
  are extinct

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Osteichthyes, Continued

• Structure
• Secretes mucus that gives characteristic
  sliminess (reduces swim drag)
• Faster fishes fusiform (tapering on both ends,
  like a shark)
• Lateral line system like sharks
• No placoid scales
• Fins median and paired with rays of
  cartilage/bone
• Good anatomy picture on p639

Selene vomer
http//tolweb.org/tree?groupVertebrata
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Osteichthyes, Continued

• Have both good eyesight and good smelling
• Nervous system
• Brain with sm. olfactory lobes and cerebrum, lg.
  optic lobes
• Circulation
• Two chambered heart, arterial and venous systems,
  four pairs of aortic arches
• Reproduction
• Varies
• External fertilization (Oviparous) fertilization
  after eggs laid
• Internal fertilization and birthing in some
  species

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Osteichthyes, continued
Digestive System and Organs (Actinopterygii)
http//animaldiversity.ummz.umich.edu/site/account
s/specimens/Actinopterygii.html
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Osteichthyes, Continued

• Respiration
• Gills supported by bony gill arches covered by
  common operculum, allows fish to breathe while
  stationary
• Swim bladder, contributes to buoyancy
• Some fish have connection between this and the
  digestive tract to allow the extraction of oxygen

http//trc.ucdavis.edu/mjguinan/apc100/modules/Res
piratory/gill/gill0/gill3.html
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Osteichthyes, continued
Respiratory System and Organs (Actinopterygii)
http//animaldiversity.ummz.umich.edu/site/account
s/specimens/Actinopterygii.html
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S. California Species
Horn Shark Heterodontus francisci Brown to grey
coloration. Large spines in front of each dorsal
fin. Length to 4 feet. Range Monterey
California to Gulf of California
California Stingray Common, found across
coastline.
http//goldenstateimages.com/index.htm
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S. California Species
Rockfish Found along California coastline.
California Black Sea Bass Stereolepis gigas Rare
fish along the California coast. Found along
rocky reefs and in kelp forests. Size can range
to over 7 feet in length, with weights in excess
of 500 pounds. Individuals can live to over 100
years of age.
Guadalupe Cardinal Fish Apogon guadalupensis Range
San Clemente Island California to Cabo San
Lucas Baja California. The only cardinal fish
found in Southern California and Baja California.
http//goldenstateimages.com/index.htm
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S. California Species
Gamefish Yellowtail Seriola lalandi Range Found
worldwide in temporate and subtropical seas. Off
the coast of California, highly migratory. During
summer months they are found in large numbers off
Southern California, having traveled northward up
the coast from Baja. Often found around drift
kelp or other drifting flotsam. Can reach a size
of two feet within about two years.
Garibaldi Hypsypops rubicundus Range Monterey
Bay to Magdalena Bay, Baja California Found along
coastal reefs and in Kelp forests, at depths of
up to 95 feet. Very territorial, defend large
areas of reef from each other, other fish species
and almost all other intruders.
http//goldenstateimages.com/index.htm
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S. California Species
Ocean Sunfish Mola mola Range Found in tropical
temperate seas worldwide Size can range to over
10' in height with weights in excess of 3000
pounds, although rarely to this size off
California. Pelagic. Along the California coast
Molas are often found beneath drift kelp being
cleaned of parasites by Medialunas and other
fishes.
http//goldenstateimages.com/index.htm
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Quiz

• Which of the following characteristics is not
  present in all members of phylum Chordata?
• A. vertebrae
• B. notochord
• C. dorsal nerve cord
• D. pharyngeal slits
• E. postanal tail
• 2. Agnathans lack which of the following
• A. Paired Fins
• B. Jaws
• C. Stomach
• D. All of the above

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Quiz, continued

• 3. What characteristic of Chondrychthyes allows
  for enlarged surface area of the intestines?
• A. Operculum
• B. Otoliths
• C. Spiral valve
• D. Oviparocules
• 4. What physical feature gives the osteichthyes
  buoyancy?
• A. Aveoli
• B. Swim bladder
• C. Life jacket
• D. CO2 gas
• 5. Osteichthyes are
• A. Poriforous
• B. Viviparous
• C. Oviparous
• D. Ovoviviparous

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Quiz, Answers

• 1. Which of the following characteristics is not
  present in all members of phylum Chordata?
• A. vertebrae
• 2. Agnathans lack which of the following
• D. All of the above
• 3. What characteristic of Chondrychthyes allows
  for enlarged surface area of the intestines?
• C. Spiral valve
• 4. What physical feature gives the osteichthyes
  buoyancy?
• B. Swim bladder
• 5. Osteichthyes are
• C. Oviparous

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Can You Find the Cabezon?