FISH (and chordates)

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FISH(and chordates)
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What is a chordate?

• Members of the ANIMAL KINGDOM and the PHYLUM
  CHORDATA
• They have a dorsal, hollow nerve cord and a
  notocord

Most chordates are vertebrates (SUBPHYLUM
VERTEBRATA)
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A few Chordates that are NOT vertebrates include
a group know as protochordates. These include
Sea Squirts or Tunicates
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and Lancelets
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Protochordate Anatomy
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What is a vertebrate?
---Animals with a backbone or vertebral column
(endoskeleton) ----Have spinal cord - dorsal,
hollow nerve cord ----Front end of spinal cord
develops a brain
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Vertebrate Classes

• Jawless Fish (lamprey, hagfish)
• Cartilage Fish (sharks, rays)
• Bony Fish (salmon, catfish, goldfish)
• Amphibians (frogs, salamanders)
• Reptiles (lizards, turtles)
• Birds (sparrows, hawks)
• Mammals (humans, whales, cats..)

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Fish Classification

• Kingdom- Animalia
• Phylum- Chordata
• Sub Phylum- Vertebrata
• Classes- Agnatha, Chondrichthyes, Osteichthyes

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General Fish Characteristics

• Gills
• Backbone (vertebrae)
• Paired Fins
• Single Loop Circulation

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Fish have a two chambered heart and single loop
circulation blood is passed over the gills where
it picks up oxygen, goes to the body and returns
to the heart
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Fish Respiration

• Water flows over Gills as fish opens mouth and
  swims.
• Water flows opposite direction of blood flow.

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Fish Respiration

• O2 diffuses from the water into the blood.
• Gills are made of thousands of gill filaments.
• Gills are covered by the Operculum.

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The Nervous System
- Cerebrum - thinking, voluntary activities-
Cerebellum - coordination- Medulla Oblongata -
functions of internal organs - Lateral Line
System - senses vibrations
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Reproduction

• Most fish lay eggs that are fertilized externally
  - called spawning
• Some fish bear live young

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Fish Adaptations

• Lateral Line System- used to detect vibrations,
  orient the fish in water, it is a line of cells
  running down the side of the fish.
• Operculum- gill cover, movement of operculum
  allows more water to be drawn in.
• Swim Bladder- a gas filled sac that helps the
  fish maintain buoyancy. Sharks dont have a swim
  bladder!
• Fins- Dorsal, Caudal, Pectoral, Pelvic, Anal.

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Class Agnatha

• Jawless fish Lampreys, Hagfish

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Types of Agnathans

• Hagfish- Ocean scavengers, not much is known
  about them.
• Lamprey- fresh and salt water, they are parasitic
  and prey on other fish.
• Both have cartilagenous skeletons and
  sucker-like mouths.

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Class Chondrichthyes
Sharks and Rays

• Cartilage skeletons, no bones
• No operculum, must keep moving to breathe.
• Have live births.
• Special scales feel like sandpaper.

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Types of Chondrichthyes

• Sharks
• Sharks are adapted for a predatory lifestyle.
• Cartilage skeletons, no bones stiff pectoral fins
  (speed).

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Types of Chondrichthyes

• Rays

Manta, and Sting Rays- live in shallow water,
have mouths located on the underside, are fairly
docile, wide flat bodies and wing-like fins that
are flexible.
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Class Osteichthyes

• Bony Fish Salmon, Carp, Tuna

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Types of Osteichthyes

• Ray Finned
• Most fish are this type
• Fins are supported by bony structures called
  Rays.

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Types of Osteichthyes

• Lobe Finned
• Fins are long, fleshy, muscular, supported by
  central core of bones.
• Thought to be ancestors of amphibians.
• Examples are Coelacanth, Lungfish