Phylum: Chordata

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• Phylum Chordata
• Vertebrates
• Fish and Amphibians

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Vertebrate Characteristics

• To be in the phylum Chordata you must have these
  four characteristics at some point in your
  development
• 1. dorsal, hollow nerve cord (backbone)
• 2. a notochord (most when embryos)
• 3. pharyngeal pouches (turn into gills)
• 4. tail that extends beyond the anus

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Fishes

• Fishes are aquatic vertebrates which have
• Paired fins - movement
• Scales protection (can tell age of some fish by
  counting the rings)
• Gills exchanging oxygen and carbon dioxide

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Groups of Fish

• 1. Jawless Fish
• no teeth or jaws
• Keep notochord as adults
• Many are parasites, no swim bladder
• Examples
• hagfish
• and
• lampreys

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Groups of Fish

• 2. Cartilaginous Fish
• Skeleton made of cartilage
• Tooth-like scales covering skin
• 350 species most are under 3 feet
• Teeth are replaced when worn out 20,000 in
  lifetime
• Examples sharks, rays, skates

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Groups of Fish

• 3. Bony Fish called ray-finned fish
• Very diverse group
• Most have a swim bladder
• Anadromous fish can move from salt to fresh water

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Amphibians

• Amphibian means double life water and land
• Larvae- use gills- live in water
• Adults use lungs live on land
• Moist skin
• No scales
• No claws
• Tympanic membrane behind eye (ear)

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Life cycle of Frogs
Surinam Frog After the female lays her pea-sized
eggs, the male places them on her back and pushes
them into her spongy skin. The eggs incubate as
mom's new skin slowly develops and covers them,
keeping them safe and out of sight. They then
hatch out of her back.
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Groups of Amphibians

• 1. Salamanders
• Long bodies and tails
• Four legs
• Carnivores
• Live in moist woods
• Some keep gills their entire lives

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Groups of Amphibians

• Frogs and Toads
• Frogs long legs for jumping and they are
  closely tied to water.
• Toads short legs and often live in moist
  woods or even deserts.

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Groups of Amphibians

• 3. Caecilians legless animals that live in
  water or burrow in moist soil. Some feed on
  termites. Fish like scales in their skin.