These are your notes for fish history

1. Fish History
By Mr. “I love fish” Chapman

2. Fish History
• First fossils were found about 425-500 MYA
• First fish fossils came from an Ostracoderm.
• “Plate skin”

3. Ostracoderm
• Poorly developed fins
and no jaw.
• First animal with a
backbone.

4. More Info
• Ostracoderms become
extinct and two
groups of fish evolved
from them.

5. Placoderms
• First group was the Placoderms, which
appeared about 395 MYA.
• They had thick bony plates with paired
fins.
• Their upper jaw was fused to the skull and
the lower jaw was hinged to the skull.

6. Placoderms

7. Placoderms
• Placoderms became extinct about 396 MYA
• Class: Chondrichthyes evolved from Placoderms.
• Chondrichthyes
– Chondra means ”cartilage”
– Ichthyic means ‘fish”
• Cartilaginous fish: 350 species
• (most sharks)
• Ex. Sharks, Rays, Skates

8. Info
• The 2nd group to
evolve from
Ostracoderms was the
Acanthodians.
• The appeared about
410 MYA
• First fish with both
jaws are movable

9. Acanthodians
• Acanthodians evolved
into Class:
Osteichthyes.
• Osteichthyes “Bony
Fish”