John Wiley & Sons
Wiley: Earth Through Time: Life of the Paleozoic: Phylum Chordata
Learn about the evolution of life in the Paleozoic Era based on fossil evidence of the five classes of fishes. Read about the role these chordates played in the evolution of tetrapods.
Bagheera
Bagheera.com: Extinct in the Wild Blue Pike
The blue pike went extinct in 1970 due to many human causes. This article outlines what happened to the fish and has some good thought-provoking questions at the end.